Earth and Life Science Notes PDF

1ST SEMESTER (1st Quarter) #### What is Science - Science is derived from a Latin word ***'Scientia'*** which comes from the verb ***'scire'***, which means "to know". - Science is a large and systematized body of knowledge based on facts, truths, and evidence through actual experienc...

1ST SEMESTER (1st Quarter) #### What is Science - Science is derived from a Latin word ***'Scientia'*** which comes from the verb ***'scire'***, which means "to know". - Science is a large and systematized body of knowledge based on facts, truths, and evidence through actual experience and observation over a long period of time. #### Branches of Science - Science can be Pure and Applied. - **Pure science** deals with knowing or understanding theories and principles while **applied science** deals with how these theories and principles can be used to developed and invent new products. - Science are further divided into two: **Natural Science** and **Social Science**. - NATURAL SCIENCE deals with the study of nature while; - SOCIAL SCIENCE deals with the study of Society. - **Natural Science** is divided into Physical Science and Biological Science. - **Physical Science** is the study of matter and energy. It comprises important concepts in physics, chemistry, and Earth Science (geology, astronomy, meteorology etc.,) - **Biological Science** is the study of living things and their parts, actions and process. It comprises the concepts in biology, zoology, botany, taxonomy, pathology, cytology and others. #### The main Branches of Earth Science - **Geology** - study of solid Earth, the materials and processes that operate beneath and upon the Earth's surface. - **Meteorology** -- study involve primarily the atmosphere, weather events, and variables that affect weather conditions such as pressure and temperature. - **Oceanography** - also known as oceanology, the study of the composition and movements of seawater, as well as coastal process, seafloor topography, and marine life. - **Astronomy** -- deals with the of study of the universe, our celestial objects such as stars, galaxies, planets, moons, asteroids, comets, and nebula. - **Cosmology** -- a branch of science that deals with the study of the universe as a whole. Scientist who are experts in this study, known as ***cosmologists,*** study and analyze the changes in the structure and features of the universe. #### Theories on the Origins of the Universe 1. **The Creationist Theory** - This theory state that God, the Supreme being created the whole universe out of nothing. The proof can be read in the Holy Bible stipulating that God created the heavens and the Earth including human. 2. #### Steady State Theory - It was proposed by Herman Bondi, Thomas Gould and Fred Hoyle. - The theory suggests that the universe has always been there and always be present. - The theory was then rejected after the discovery of redshift by Edwin P. Hubble because it showed that the universe was not static, it continuously expanding. 3. #### Big Bang Theory - It is the most acceptable theory about the origin of the universe. - The first proponent of the theory was a Belgian priest, George Lemaitre. - It was supported by Edwin P. Hubble, Arno Penzias, and Robert Wilson who presented pieces of evidences to support. - According to this theory, universe is 13.8 billion years old. #### Multiverse Theory #### The eras of the universe, from the time of the Big Bang, are listed below. - Planck Era - (All four known forces are unified.) - GUT (Grand Unified Theory) Era - (Gravity \"freezes out\" and becomes distinct.) - Electroweak Era - (The nuclear strong force \"freezes out\" and becomes distinct.) - Particle Era - (particles begin to form) - Era of Nucleosynthesis - (nuclear fusion creates Helium, and tiny amount of heavier elements) - Era of Nuclei - (electrons are not yet bound to nuclei) - Era of Atoms - (electrons recombine to form neutral atoms, and the first stars are born) - Era of Galaxies - (Galaxies begin to form, leading up to the present) #### What is Solar System - "Solar" pertains to the sun and "System" pertains to the heavenly bodies that are attracted to the gravitational pull of the sun. - The solar system refers to the collection of celestial bodies, including the Sun, planets, moons, asteroids, comets, and other smaller objects, that are gravitationally bound to the Sun. #### How did the Solar System come about? - Universe are composed of HOT, TINY PATICLES mixed with LIGHT and ENERGY. - As the universe expanded, it cooled down, and the particles slow down and group together forming the light elements (H & He). - Atoms group together forming stars, and with the presence of gravity, galaxies were formed. #### Hypothesis explaining the origin of the solar System: - **ENCOUNTER** - Rogue star passed by the sun, gas and matter were removed from both stars and become planets. - **NEBULAR** - is an explanation for the origin of Solar System. The word NEBULA is a Latin word CLOUD, and according to the explanation, stars are born from clouds of gas and dust. According to this theory, our own Solar System formed about 4.6 billion years ago, and others are forming today in distant nebulae. - A gas and dust contract due to gravity forming a disk that began to rotate forming within its center the protosun, within the disk, formed the planets. #### Stages Description - **Collapse** - The Solar System comes from high temperature gas ball. The mass of gas ball collapse. And then heating and then become disk shaped. - **Spinning** - The disk spinning faster and faster, so that the no part of the disk that was thrown out and then the temperature decreased. - **Flattening** - The disk becomes a sphere due to rotation, because of fast rotation, some of the fog from gas ball mass escape. - **Condensation** - Some fog formed the core of the largest mass in the middle, while the small part formed around cooling process. - **Accretion** - The cores of smaller masses turn into planets, while most of the remains in a state of high temperature flare and called the sun. ### PROTOPLANET - Massive cloud of gas and dust rotated slowly in space, the cloud shrank under the influence of its own gravitation. - Most materials gathered around its own center. Temperature become so high that fuel a powerful reaction (fusion of H) giving birth to the sun. #### Why Earth is habitable? - HABITABLE ZONE - Is the area around a star where it is not too hot and not too cold for liquid water to exist on the surface of surrounding planets. - The distance of the earth orbits the sun is just right for water to remain a liquid. - Habitable Zone is also called "Goldilocks Zone" #### The Planets in the Solar System - There are two main categories of planets (1) Terrestrial Planets/Rocky planets, (2) - #### Terrestrial Planets/Rocky planets: - These planets are relatively small in size and in mass. A terrestrial planet has a solid rocky surface, with metals deep in its interior. - They are very heavy. - They move slowly in space. - They have no rings and few moons (if any). - #### Jovian Planets/Gas giants: - These planets have larger sizes and masses. Jovian planets do not have solid surfaces. They are sometimes called gas giants because they are large and made mostly of gases. - They are very light for their size. - They move quickly in space. - They have rings and many moons. #### The Eight (8) Planets in our Solar System: 1. Mercury, the nearest planet to the Sun in our solar system, and does not have any moons. It has craters on the surface, similar to Earth\'s moon. It can be both extremely hot and cold on Mercury. And its appearance resembles a small, grayish sphere. 2. Venus, almost equal in size to Earth, It is sometimes referred to as Earth\'s twin due to its size and density. Even though Mercury is closest to the Sun, Venus is the hottest planet in our solar system; its surface temperature is approximately 475 degrees Celsius. This extreme heat is a result of Venus\'s potent greenhouse effect. 3. Earth is our home planet; the third planet from the Sun, is the only place we know of that can sustain and support life. Earth is the largest of the four closest planets to the Sun, which are all made of rock and metal. 4. Mars, a cold, dry, dusty planet with a thin atmosphere, is the fourth planet from the Sun. it is called the "Red Planet" because of its color due to its iron minerals that's why Mars appears red because of iron oxide, or rust, in its soil. Mars has the largest volcano in our solar system called Olympus Mons (3x's size of Mt. Everest). 5. Jupiter is the largest planet and a gas giant, mainly composed of hydrogen and helium. One of its most famous features is the \"Great Red Spot,\" a massive storm that has been active for centuries. 6. The second-largest planet in our solar system, Saturn, is located at a distance of six planets from the Sun. Saturn is a gas giant primarily composed of hydrogen and helium. Titan is one of Saturn\'s 83 moons. Saturn is also famous for its rings. 7. Uranus, it has hydrogen, helium, ammonia, and methane. What makes Uranus unique is its sideways spin, similar to rolling a ball along the ground but with its top and bottom facing the sides. 8. Neptune, positioned as the eighth and most distant planet from the Sun in our solar system, is made up mostly of hydrogen and helium. It is also one of the coldest planets in our solar system. #### What makes up the universe? - The other members of the Solar System are: - Asteroids - Meteoroids / Comets - The sun - The moon - The Stars #### Why Earth is habitable? - Earth is the only planet that harbor life. - It is located in the "Habitable Zone" - (the area around a star where it is not too - hot and not too cold). - It has an atmosphere that shields us from harmful radiation coming from the sun. #### Factors that Makes the Planet Habitable: - Temperature - Water - Atmosphere - Energy - Nutrients #### Earth Subsystem ### GEOSPHERE - GEO Means Earth. - Solid portions of the Earth. It includes rocks, sediments, soils, and surface landforms. - Earth's Interior Layers: It includes the core, mantle, and crust of the Earth. ### HYDROSPHERE - HYDRO means Water - The water part of the Earth which circulates among oceans, continents, glaciers, rivers, and lakes - Approximately 70% of the Earth's surface is water and 30% of the Earth's surface is land. ### ATMOSPHERE - The Earth is surrounded by a blanket of air, which we call the atmosphere - It is the gaseous layer above the Earth's surface, primarily composed of 78% nitrogen and 21% oxygen. Other gases like argon, carbon dioxide, carbon monoxide, ozone, and other inert gases made the remaining 1%. - Life on Earth is supported by the atmosphere because animals and plants need both carbon dioxide and oxygen. ### BIOSPHERE - The zone of Earth where all forms of life exist; - this includes life on land, in the sea, rivers, and - even life that we cannot see with the naked eye. #### How this spheres are interacting each other? #### Example 1: #### What is inside Earth? - Earth is made of several Layers. - If we could take a chunk out of the Earth, we would see that it is made up of different layers. - Each Layer has its own Characteristic and Properties - in terms of Composition, and in terms of Physical Properties. #### Physical Properties Vs. Composition - Composition - What it's made of - Physical properties - it talks about the Characteristic that is unique and helps to identify the substance (Temperature, size, Shape, Colour) #### The Earth is divided into three main Layers - The Crust, Mantle, and Core. And these Layers are then subdivided into smaller layers or parts. - HAVE YOU SEEN AN EGG? - The Layers of the Earth like the Layers of an Egg.  ### CRUST: - Outermost Layer or the thinnest layer - Where we live - It is made of solid rocks - It is the surface of earth that consist of all the mountains, water, soil and land features. - Contains the Oceanic Crust and Continental Crust. - The crust of the Earth is broken into many pieces called plates. The plates \"float\" on the soft, semi-rigid layer and what we called asthenosphere. - The boundary zone between the crust and the mantle is called the Mohorovicc Discontinuity or "Moho"  #### Mantle - Thickest layer, located below the crust and it is the largest layer. - Divided into two (2) parts: - Upper mantle and Lower mantle - Most of the mantle is solid rock and also called as Lithosphere - The lower mantle rock is softer and also called as Asthenosphere - Take Note: "Litho" means "stone" and "Asthens" means "weak" #### Lithosphere - The outermost, rigid layer of Earth - The lithosphere is made of the crust and the upper part of the mantle. - The lithosphere is divided into tectonic plates. #### Asthenosphere - The upper layer of the earth\'s mantle, below the lithosphere that is a soft or weak and fluid layer responsible for driving plate tectonics motion. ### CORE - HOT! - High pressure - Made up of Iron and Nickel (metals) - Divided into two (2) parts: Inner Core and Outer Core #### Outer Core vs. Inner Core - The core is divided into two parts: - Outer Core: Liquid iron and made up of nickel - Inner Core: Solid iron and nickel, it solid because of all the pressure of the rest of the earth surrounding it. #### What are Minerals? #### Characteristics of Minerals 1. naturally occurring - a product of Earth's natural processes 2. inorganic- it must be product of Earth's physical processes. 3. homogeneous solid- minerals should have definite volume and rigid shape 4. definite chemical composition---represented by a chemical formula 5. orderly crystalline structure- atoms of minerals are arranged in an orderly and repeating pattern #### Properties of Minerals 1. Color - mineral's color may change depending on the surface. 2. Streak - color of mineral in powdered form. 3. Hardness - minerals resistance to scratching 4. Cleavage - mineral's resistance to being broken and fracture 5. Amount of transparency - ability to allow light to pass through it. This is affected by chemical makeup of the mineral sample. g. Luster - how light is reflected off a surface 6. Tenacity - describes the minerals reaction to stress. - Brittleness - a mineral turn into powder - Malleability a mineral can be flattened by pounding with a hammer. - Ductility - A mineral can be stretched into wire. - Flexible but Inelastic - Minerals are bent but they remain in the new position. - Flexible and elastic- Minerals are bent, and they bring back to their original position. - Sectility - ability of minerals to be sliced by a knife. ### ROCKS - Petrology is the scientific study of rocks. Rocks are combined aggregation of minerals. Petrologist classified rocks based on how they were formed. In general, rocks are classified as igneous, sedimentary, and metamorphic rock. - Earth is a solid rock to a depth of 2,900 kilometers, where mantle meets the liquid outer core. A **rock** is a naturally occurring solid aggregate of one or more minerals. The aggregate minerals forming the rocks are held together by chemical bonds. Grains can be different in color, texture, and sizes. Geologists then group rocks into three categories based on how the rocks form: igneous sedimentary and metamorphic rock. **Petrology** is the scientific study of rocks. Petrologists classify rocks based on how they were formed. #### Three types of Rocks 1. **Igneous**- formed from hardening and **crystallization of magma** or molten material that originates deep within the earth. #### Two types of igneous rock: A. **Extrusive/Volcanic rock** - forms when magma makes its way to Earth's surface B. **Intrusive/Plutonic** - It cools slowly beneath the Earth surface and are created by magma. The intrusive igneous rocks have very large crystals (coarse grained) #### Igneous rocks are classified based on 1. **Composition** - FELSIC - light in color; feldspar and silicates - MAFIC - dark in color; made up of magnesium and iron - INTERMEDIATE -- between mafic and felsic - ULTRAMAFIC - very dark color 2. **Texture** - overall appearance of rock - Aphanistic - fine grained - Phaneritic - coarse grained - Porphyritic- large crystals with small crystals Glassy-non ordered solid from rapid quenching. - Pyroclastic- composite of ejected fragments Examples:  2. **Metamorphic** - forms from pre-existing rocks: either igneous, sedimentary. Examples: Quartzite, marble, slate, phyllite #### 2 types of metamorphism 1. **Regional** - due to changes in pressure and temperature over large region of the crust 2. **Contact** - mainly by heat due to contact with magma #### Classification: a. **Texture** - refers to the size arrangement ad grains within the rock. b. **Foliation** - any planar arrangement of mineral grains or structural features within the rock. #### Sedimentary rocks - provide information about surface conditions that existed in the Earth's past. - Particles of sand, shells, pebbles, and other fragments of materials called sediments, accumulate in layers and over long period of time harden into rocks. - Compaction-due to increase of pressure of layered sediments it bind together to form the sedimentary rocks. #### Three types of sedimentary rocks 1. **Clastic Sedimentary rock** - formed from accumulation of clasts: little pieces of broken rocks and shells. Examples: conglomerate, breccia, sandstone, shale 2. **Chemica**l - formed when dissolved minerals precipitate from a solution. 3. **Organic** - rocks formed from the accumulation of animal debris.  ### EXOGENIC PROCESS - Exogenic processes are external processes that occur at or near the surface of Earth. - The earth's surface is composed of water and landmasses. The solid portion is made out of rocks and minerals that could experience changes either physically or chemically. The weathered materials are transported by different agents from one place to another and will settle down in a particular area. These progressions that happen is achieved by forms called exogenic processes. It includes **(weathering, mass wasting, erosion, and deposition).** - **Mechanical weathering** or **physical weathering** is the breakdown of rocks into pieces without any change in its composition. In this process, the size and shape of rocks changes and this occurs because of the following factors shown in the table below. 1. **Pressure -** Due to tectonic forces, granite may rise to form mountain range. After the granite ascends and cools, the overlying rocks and sediments may erode. At the point when the pressure diminishes, the rock expands, cools, and became brittle and fractured. 2. **Temperature** - Rocks expand and are fractured when expose to high temperature. However, if the temperature drops to 0°C (freezing point of water), it also expands and causes fracture. 3. **Frost Wedging** - Generally, rocks have fracture in its surface and when water accumulates in the crack and at that point freezes, the ice expands and breaks the rock apart. 4. **Abrasion** - The breakdown of rocks is caused by impact and friction. This primarily occurs during collision of rocks, sand, and silt due to current or waves along a stream or seashore causing sharp edges and corners to wear off and become rounded. 5. **Organic Activity** - The roots grow causing penetration into the crack, expand, and in the long run, break the rock. 6. **Human Activities** - Activities such as digging, quarrying, denuding forests and cultivating land contribute to physical weathering. 7. **Burrowing Animals** - Animals like rats, rabbits and squirrels excavate into the ground to create a space for habitation. - In chemical weathering, there are changes in the composition of rocks due to the chemical reactions presented below. 8. **Dissolution** - It occurs in specific minerals which are dissolved in water. Examples of these minerals are Halite (NaCl) and Calcite (CaCO3). The formation of stalactites and stalagmites in caves are brought about by this chemical reaction. 9. **Hydrolysis** - Rock-forming minerals like amphibole, pyroxene, and eldspar react with water and form different kinds of clay minerals. 10. **Oxidation** - It is the response of oxygen with minerals. If the iron oxidizes, the mineral in rocks decomposes. Rusting is an example of this chemical reaction. #### Factors that affect the type, extent, and rate at which weathering takes place: 1. **Climate --** areas that are cold and dry tend to have slow rates of chemical weathering and weathering is mostly physical; chemical weathering is most active in areas with high temperature and rainfall. 2. **Rock type --** the minerals that constitute rocks have different susceptibilities to weathering. The susceptibility of minerals (from high to low) roughly follows the inverse of the order of crystallization of minerals in the Bowen's reaction series. Thus, olivine which crystallizes first is the least resistant whereas; quartz which crystallizes last is the most resistant. 3. **Rock structure --** rate of weathering is affected by the presence of joints, folds, faults, bedding planes through which agents of weathering enter a rock mass. Highly jointed/ fractured rocks disintegrate faster than a solid mass of rock of the same dimension. 4. **Topography --** physical weathering occurs more quickly on a steep slope than on a gentle one. On a gentle slope, water may stay longer in contact with the rocks, hence chemical weathering is enhanced. 5. **Time --** length of exposure to agents of weather determines the degree of weathering of a rock. ### EXOGENIC PROCESS (MASS WASTING) 1. **Mass Wasting** as the downslope movement of rock, regolith, and soil under the direct influence of gravity. Gravity as the main immediate agent in mass movement. 2. #### Factors controlling in mass wasting: a. **Slope Angle** - Component of gravity perpendicular to the slope which helps hold the object in place - Component of gravity parallel to the slope which causes shear stress and helps move objects downslope. b. #### Role of water - Water has the ability to change the angle of repose - (the steepest slope at which a pile of unconsolidated grains remains stable). - Addition of water from rainfall or snowmelt adds weight to the slope. - Water can reduce the friction along a sliding surface c. #### Presence of troublesome earth materials - **Expansive and hydro compacting soils** -- contain a high proportion of smectite or montmorillonite which expand when wet and shrink when they dry out. - **Sensitive soils** -- clays in some soils rearrange themselves after dissolution of salts in the pore spaces. Clay minerals line up with one another and the pore space is reduced. - **Quick clays** -- water-saturated clays that spontaneously liquefies when disturbed. d. #### Weak materials and structures - Become slippage surfaces if weight is added or support is removed (bedding planes, weak layers, joints and fractures, foliation planes. 3. #### Mass Wasting Process e. **Slope failures** - sudden failure of the slope resulting in transport of debris downhill by rolling, sliding, and slumping. - **Slump** -- type of slide wherein downward rotation of rock or regolith occurs along a curved surface - **Rock fall and debris fall**-- free falling of dislodged bodies of rocks or a mixture of rock, regolith, and soil in the case of debris falls - **Rock slide and debris slide**- involves the rapid displacement of masses of rock or debris along an inclined surface f. **Sediment flow** -- materials flow downhill mixed with water or air. - **Slurry flow** -- water-saturated flow which contains 20-40% water; above 40% water content, slurry flows grade into streams. - **Solifluction** -- common wherever water cannot escape from the saturated surface layer by infiltrating to deeper levels; creates distinctive features: lobes and sheets of debris - **Debris flow** -- results from heavy rains causing soil and regolith to be saturated with water; commonly have a tongue-like front. - **Mud flow** -- highly fluid, high velocity mixture of sediment and water; can start as a muddy stream that becomes a moving dam of mud and rubble - **Granular flow** -- contains low amounts of water, 0-20% water; fluid-like behavior is possible by mixing with air. - **Creep** -- slowest type of mass wasting requiring several years of gradual movement to have a pronounced effect on the slope - **Grain flow** -- forms in dry or nearly dry granular sediment with air filling the pore spaces such as sand flowing down the dune face - **Debris avalanche** -- very high velocity flows involving huge masses of falling rocks and debris that break up and pulverize on impact 4. #### Subaqueous Mass Wasting #### Three types: 1. **Submarine slumps -** similar to slumps on land 2. **Submarine debris flow** -- similar to debris flows on land 3. **Turbidity current** -- sediment moves as a turbulent cloud 5. #### Events That Trigger Mass Wasting Processes - **Shocks and vibrations** -- earthquakes and minor shocks such as those produced by heavy trucks on the road, man-made explosions - **Slope modification** -- creating artificially steep slope so it is no longer at the angle of repose - **Undercutting** -- due to streams eroding banks or surf action undercutting a slope - **Changes in hydrologic characteristics** -- heavy rains lead to water-saturated regolith increasing its weight, reducing grain to grain contact and angle of repose. - **Changes in slope strength** -- weathering weakens the rock and leads to slope failure. - **Volcanic eruptions** -- produce shocks; may produce large volumes of water from melting of glaciers during eruption, resulting to mudflows and debris flows 6. #### Landslide Warning Signs 1. Springs, seeps, or saturated ground in areas that have not typically been wet before. 2. New cracks or unusual bulges in the ground, street pavements or sidewalks. 3. Soil moving away from foundations. 4. Ancillary structures such as decks and patios tilting and/or moving relative to the main house. 5. Tilting or cracking of concrete floors and foundations. 6. Broken water lines and other underground utilities. 7. Leaning telephone poles, trees, retaining walls or fences. 8. Offset fence lines. 9. Sunken or down-dropped road beds. 10. Rapid increase in creek water levels, possibly accompanied by increased turbidity (soil content). 11. Sudden decrease in creek water levels though rain is still falling or just recently stopped. 12. Sticking doors and windows, and visible open spaces indicating jambs and frames out of plumb. 13. A faint rumbling sound that increases in volume is noticeable as the landslide nears. 14. Unusual sounds, such as trees cracking or boulders knocking together, might indicate moving debris. ### EXOGENIC PROCESS (EROSION AND DEPOSITION) ### AGENTS OF EROSION 1. **Running water --** encompasses both overland flow and stream flow. Differentiate overland flow and streamflow. It is the primary agent of erosion on Earth. #### Factors that affect stream erosion and deposition - **Velocity** -- dictates the ability of stream to erode and transport; controlled by gradient, channel size and shape, channel roughness, and the amount of water flowing in the channel - **Discharge** -- volume of water passing through a cross-section of a stream during a given time; as the discharge increases, the width of the channel, the depth of flow, or flow velocity increase individually or simultaneously - **Styles of erosion**: Vertical erosion (downcutting), lateral erosion, headward erosion - **Streamflow erosion occurs through**: Hydraulic action, abrasion, solution - **Streams transport their sediment load in three ways**: in solution (dissolved load), in suspension (suspended load), sliding and rolling along the bottom (bed load) #### Ocean or sea waves - Wind speed; wind duration; fetch (distance the wind has travelled across water) - Orbital motion of water in waves. In deep water, there is little or no orbital motion at depths greater than half the wavelength. #### Ways on how waves erode and move sediment along the shore: - **Shoreline erosion processes**: Hydraulic action, abrasion, corrosion - **Transport by waves and currents:** Longshore current, beach drift #### Features created by wave erosion and deposition: a. **Erosional features**: wave-cut cliff, wave-cut platform, marine terrace, headland, stacks and sea arches b. **Depositional features**: beach, spit, baymouth bar, tombolo, barrier island 3. **Glaciers --** a moving body of ice on land that moves downslope or outward from an area of accumulation #### Types of glaciers: 1. **Valley (alpine) glaciers --** bounded by valleys and tend to be long and narrow 2. **Ice sheets (continental glaciers) --** cover large areas of the land surface; unconfined by Modern ice sheets cover Antarctica and Greenland 3. **Ice shelves --** sheets of ice floating on water and attached to the land. They usually occupy coastal embayment. - **Processes responsible for glacial erosion**: ***[Plucking]*** (lifting pieces of bedrock beneath the glacier) and ***[abrasion]*** (grinding and scraping by sediments already in the ice). - **Landforms created by valley glacier erosion**: cirque, tarn, arête, horn, hanging valley, u shaped valley, pater noster lakes, fjord - **Landforms created by continental glaciers**: roche, moutonnée #### Two Types of Deposits by Glaciers: 1. All glacial deposits are called **glacial drift**, and are comprised of two types: - **till**, deposited directly by ice, unsorted, and composed of many different particle sizes - **Stratified drift**, deposited by the glacial meltwater and thus has experienced the sorting action of water. 2. **Moraines** are ridges of till, classified according to their position relative to the glacier: lateral (edge of valley glaciers) moraine; end (front or head of glacier) moraine; ground (base of glacier) moraine; and medial (middle) moraine. 4. #### Wind - **Wind erodes by:** deflation (removal of loose, fine particles from the surface), and abrasion (grinding action and sandblasting). - **Wind, just like flowing water, can carry sediments such as:** (1) bed load (consists of sand hopping and bouncing through the process of saltation), and (2) suspended load (clay and silt-sized particles held aloft). - **Features created by wind erosion**: blowout and desert pavement created by **deflation**, venti facts and yardangs resulting from **abrasion** - **Two types of wind deposits:** (1) ***[dunes]*** which are hills or ridges of wind-blown sand, and (2) ***[loess]*** which are extensive blankets of silt that were once carried in suspension. **There are six major kinds of dunes:** 1. barchan dunes 4. longitudinal dunes 2. transverse dunes 5. parabolic dunes 3. barchanoid dunes 6. star dunes #### Groundwater #### karst topography and its associated landforms. - **Karst topography** ---a distinctive type of landscape which develops as a consequence of subsurface solution. It consists of an assemblage of landforms that is most common in carbonate rocks, but also associated with soluble evaporate deposits. 1. **Cave/Cavern** -- forms when circulating groundwater at or below the water table dissolves carbonate rock along interconnected fractures and bedding planes. 2. **Sinkholes (Dolines**) -- circular depressions which form through dissolution of underlying soluble rocks or the collapse of a cave's roof. 3. **Tower karst** -- tall, steep-sided hills created in highly eroded karst regions. #### Gravity a. **Mass wasting** --- the downslope movement of soil, rock, and regolith under the direct influence of gravity b. #### Factors that control mass wasting processes include: - As the slope angle increases, the tendency to slide down the slope becomes greater. - Role of water: adds weight to the slope, has the ability to change angle of repose, reduces friction on a sliding surface, and water pore pressure reduces shear strength of materials. ### ENDOGENIC PROCESS - **Endogenic processes** are internal processes that occur beneath Earth. These result in reshaping of Earth's landforms. #### Heat in Earth's Interior - Heat energy plays a vital role in our planet. It is one of the extreme factors in what makes the world livable. If you think of a volcano, you know Earth must be hot inside. - The heat inside of our planet moves continents, build mountains and causes earthquakes, but where does all this heat inside the earth come from? - #### Sources of heat in our planet can be identified as Primordial and Radiogenic heat. - During the early formation of the Earth, the internal heat energy that gradually gathered together by means of dispersion in the planet during its few million years of evolution is called ***Primordial heat***. - The major contribution of this internal heat is the accretional energy -- the energy deposited during the early formation of a planet. The core is a storage of primordial heat that originates from times of accretion when kinetic energy of colliding particles was transformed into thermal energy. This heat is constantly lost to the outer silicate layers of the mantle and crust of the earth through convection and conduction. In addition, the heat of the core takes tens of thousands of years to reach the surface of the earth. Today, the surface of the earth is made of a cold rigid rock since 4.5 billion years ago, the earth's surface cools from the outside but the core is still made of extremely hot material. - On the other hand, the thermal energy released as a result of spontaneous nuclear disintegration is called ***Radiogenic Heat***. - It involves the disintegration of natural radioactive elements inside the earth -- like Uranium, Thorium and Potassium. Uranium is a special kind of element because when it decays, heat (radiogenic) is produced. Estimated at 47 terawatts (TW), the flow of heat from Earth\'s interior to the surface and it comes from two main sources in equal amounts: the radiogenic heat produced by the radioactive decay of isotopes in the mantle and crust, and the primordial heat left over from the formation of the Earth. - Radioactive elements exist everywhere on the earth in a fairly significant concentration. Without the process of radioactive decay, there would be fewer volcanoes and earthquakes -- and less formation of earth's vast mountain ranges. #### Distribution of Earth's internal heat: - Simultaneous conduction, convection and radiation - Convection occurs at the mantle but not between the core and mantle or even between the asthenosphere and lithosphere (except at sea-floor spreading zones). The only heat transfer mechanism in these transition zones is through conduction. #### Sources of Heat and Heat Transfer #### Magma Formation - **Melting due to decrease in pressure (decompression melting):** The decrease in pressure affecting a hot mantle rock at a constant temperature permits melting forming magma. This process of hot mantle rock rising to shallower depths in the Earth occurs in mantle plumes, beneath rifts and beneath mid-ocean ridges. - **Melting as a result of the addition of volatiles**---**compounds that have low boiling points (flux melting**): When volatiles mix with hot, dry rock, the volatile decreases the rock's melting point and they help break the chemical bonds in the rock to allow melting. - **Melting resulting from heat transfer from rising magma (heat transfer melting):** A rising magma from the mantle brings heat with it and transfer heat to their surrounding rocks at shallower depths which may melt. #### Places where magma can form - **Mid-oceanic ridges**: the rising magma in mantle convection cell brings heat to the surface, transferring heat to the overlying rocks. The transfer of heat due to convection is accompanied by a decrease in pressure or \"decompression\" associated with the spreading of the lithospheric plates. - **Mantle plumes (hot spots):** Similar to mid-oceanic ridges, the transfer of heat and decompression result to magma generation. The source of heat for mantle plumes is much deeper. - **Subduction zones**: Oceanic crustal rocks are formed along spreading centers, typically beneath several kilometers of seawater. The presence of water during generation results to the formation of hydrous minerals. As the oceanic slab is down-thrusted along subduction zones, the change in temperature and pressure conditions brings about mineral instability (e.g. hydrous minerals) and the release of water to the surrounding hot rocks. What is Magma? -------------- A. #### Why and how magma rises up - **Density contrast**: magma is less dense than the surrounding country rock. Magma rises faster when the difference in density between the magma and the surrounding rock is greater. - ***At deeper levels**,* magma passes through mineral grain boundaries and cracks in the surrounding rock. When enough mass and buoyancy is attained, the overlying surrounding rock is pushed aside as the magma rises. Depending on surrounding pressure and other factors, the magma can be ejected to the Earth's surface or rise at shallower levels underneath. - ***At shallower levels***, magma may no longer rise because its density is almost the same as that of the country rock. The magma starts to accumulate and slowly solidifies.  - **Viscosity:** a measure of a fluid's resistance to flow. Magmas with low viscosity flow more easily than those with high viscosity. Temperature, silica content and volatile content control the viscosity of magma. - **Mafic magma** [is less viscous than silicic] **(felsic) magma** because it is hotter and contains less silica. Also, the volatiles in magma decreases viscosity. B. #### Bowen's Reaction Series (proposed by Norman L. Bowen) - Certain minerals are stable at higher melting temperature and crystallize before those stable at lower temperatures. - Crystallization in the continuous and discontinuous branches takes place at the same time. - ***Continuous branch***: contains only plagioclase feldspar, with composition changing from calcium-rich to sodium rich as temperature drops. - ***Discontinuous branch*** describes how ferromagnesian minerals in the magma are transformed as temperature changes. The early formed crystals, olivine in this case, reacts with the remaining melt as the magma cools down, and recrystallizes into pyroxene. Further cooling will transform pyroxene into amphibole. If all of the iron and magnesium in the melt is used up before all of the pyroxene recrystallizes to amphibole, then the ferromagnesian minerals in the solid rock would be amphibole and pyroxene and would not contain olivine or biotite.  - #### Important concepts derived from the Bowen's reaction series: - A mafic magma will crystallize into pyroxene (with or without olivine) and calcium-rich plagioclase that is, basalt or gabbro i̶ f the early formed crystals are not removed from the remaining magma. Similarly, an intermediate magma will crystallize into diorite or andesite, if early formed minerals are not removed. - If minerals are separated from magma, the remaining magma is more silicic than the original magma. For example, if olivine and calcium-rich plagioclase are removed, the residual melt would be richer in silicon and sodium and poorer in iron and magnesium. - When rocks are heated in high temperatures, minerals will melt in reverse order, going up the series in the Bowen's reaction series diagram. Quartz and potassium feldspar would melt first. If the temperature is raised further, biotite and sodium-rich plagioclase would contribute to the melt. Any minerals higher in the series would remain solid unless the temperature is raised further. #### Discuss the different processes by which the composition of magma may change (magmatic differentiation) - Magmatic differentiation is the process of creating one or more secondary magmas from single parent magma 1. **Crystal Fractionation** - a chemical process by which the composition of a liquid, such as magma, changes due to crystallization. - ***Crystal settling*** - denser minerals crystallize first and settle down while the lighter minerals crystallize at the latter stages. Bowen's reaction series shows that denser minerals such as olivine and Ca-rich plagioclases form first, leaving the magma more silicic. 2. **Partial Melting -** as described in Bowen's reaction series, quartz and muscovite are basically formed under low temperature conditions, making them the first ones to melt from the parent rock once exposed in higher temperature and/or pressure. Partial melting of an ultramafic rock in the mantle produces a basaltic magma. 3. **Magma mixing --** this may occur when two different magma rises up, with the more buoyant mass overtakes the more slowly rising body. Convective flow then mixes the two magmas, generating a single, intermediate (between the two parent magmas) magma. 4. **Assimilation/contamination of magma by crustal rocks -** a reaction that occurs when the crust is mixed up with the rising magma. As magma rises to the surface, the surrounding rocks which it comes in contact with may get dissolved (due to the heat) and get mixed with the magma. This scenario produces change in the chemical composition of the magma unless the material being added has the same chemical composition as the magma. ### ENDOGENIC PROCESS (METAMORPHISM) #### Metamorphism - As a response to heat, pressure, and chemically active fluids, minerals become unstable and change into another mineral without necessarily changing the composition. For example, coal, which is composed entirely of carbon, will turn into a diamond (also composed of carbon) when subjected to intense pressure. #### The mineral composition of the resulting metamorphic rock is influenced by the following: - Mineral composition of the original or parent rock - Composition of the fluid that was present - Amount of pressure and temperature during metamorphism #### Index minerals for metamorphic rocks - Bulk composition of the original rock - Attained pressure during metamorphism - Attained temperature during metamorphism - Composition of fluid phase that was present during metamorphism (Nelson, 2011). Certain minerals identified as index minerals are good indicators of the metamorphic environment or zone of regional metamorphism in which these minerals are formed. - Figure 1 is a representation of the progressive metamorphism of shale. It is not necessarily applicable to all types of parent rocks. Pelitic rocks (e.g. shale) more faithfully preserve the effects of increasing grade of metamorphism. Some rocks, however, such as pure quartz sandstone or limestone, provide very little clue as to the intensity of metamorphism (Monroe et al., 2007). - Shale can be transformed into a series of metamorphic rocks (slate, phyllite, schist, and gneiss, respectively) with increasing temperature and pressure conditions. Shale can also be transformed directly into schist or even gneiss if the change in metamorphic conditions is drastic. 2. #### Textural changes that occur to rocks when they are subjected to metamorphism - Most metamorphic textures involve foliation, which is generally caused by a preferred orientation of sheet silicates (silica minerals with sheet-like structures), such as clay minerals, mica and chlorite. - Differential stress is formed when the pressure applied to a rock at depth is not equal in all directions. If present during metamorphism, effects of differential stress in the rock's texture include the following: - Rounded grains can be flattened perpendicular to the direction of the maximum compressional force. - When subjected to differential stress field, minerals may develop a preferred orientation. Sheet silicates and minerals that have an elongated habit will grow with their sheets or direction of elongation perpendicular to the direction of maximum stress. #### Table 1: Agents of metamorphism and the associated metamorphic processes - **Foliated metamorphic rock --** minerals have been rearranged into visible layers or bands. - **Non-foliation metamorphic rock --** do not show layering or banding. - **[Metamorphism]** does not actually melt the rocks but transforms them into denser, more compact rocks. Mineral may also be rearranged due to chemical reactions involving fluids that enter rocks - **[Metamorphic Rocks]** are used for variety of purposes. - **[Slate]** is used commercially for your classroom blackboards and for pool table tops. - **[Marble]** is used in the construction of building floors and bathroom walls and counter parts. Extreme heat and pressure change the original state of an existing rock. They also change chemical composition and physical structure of existing rocks. Combinations of minerals in rocks are stable only over specific ranges of pressure and temperature. At pressure and temperature not within the ranges, the minerals form a different combinations call mineral assemblages (Kasten 2012, 290-291).  Igneous Rocks: How Are They Formed? What are Igneous rocks? ----------------------------------------------------------- #### How are igneous rocks formed? #### What are the types of igneous rocks based on their formation? **Table 1.** Differences Between Intrusive and Extrusive Rocks -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- Gabbro Diorite Granite **Figure 1.** Examples of Intrusive Rocks  #### What are the types of igneous rocks based on composition? 1. **Ultramafic Igneous Rocks** - They have a **very low silica content; less than 45% of SiO2**. - Before forming into igneous rocks, its magma has very low viscosity. - Its color is ranged too black (peridotite) to olive green (dunite). - Their density is very high. - They are rich in pyroxene and olivine minerals. - Examples of these rocks are peridotite and dunite. 2. **Mafic Igneous Rocks** - They have a **low silica content; 45-52% of SiO2.** - Before forming into igneous rocks, its magma has low viscosity; more viscous than ultramafic magma. - They have black color. - Their density is high. - They are composed of pyroxene, calcium-rich plagioclase feldspar - Examples of these rocks are gabbro and basalt. 3. **Intermediate Igneous Rocks** - They have a **high silica content; 53-65% of SiO2.** - Before forming into igneous rocks, its magma has intermediate viscosity; more viscous than the mafic magma. - Their color is gray. - Their density is intermediate. - They are composed of biotite, alkali feldspar and quartz. - Examples of these rocks are diorite and andesite. 4. **Felsic Igneous Rocks** - They have a **very high silica content; more than 65% of SiO2** - Before forming into igneous rocks, its magma has high viscosity; more viscous than the intermediate magma. - They have light color. - Their density is very low. - They are composed of quartz and alkali feldspar. - Examples of these rocks are granite and rhyolite. Peridotite -- -- -- -- ------------ ULTRAMAFIC -- -- -- -- -- -- -- -- -- -- #### What are the types of igneous rocks based on texture? - **Phaneritic texture** -- Rocks have large minerals (example: granite) - **Aphanitic texture**- The mineral grains are too small to see with the unaided eye (example: basalt) - **Vesicular texture** -- Rocks have many pits from gas escape (example: basalt) - **Porphyritic texture** -- Rocks have two (2) distinct grain sizes, large and small (example: andesite porphyry) - **Glassy texture**- Rocks do have obvious minerals (example: obsidian) ### ENDOGENIC PROCESS (CONTINENTAL DRIFT THEORY) 1. #### The continental drift hypothesis - The idea that continents fit together like pieces of a jigsaw puzzle has been around since the 1600s, although little significance was given to it. - The continental drift hypothesis was first articulated by ***Alfred Wegener***, a German meteorologist, in 1912. He proposed that a single **supercontinent, Pangaea**, separated into the current continents and moved across Earth's surface to their present locations. He published his work through a book entitled '**The Origin of Continents and Oceans' in 1915.** - Until the 1950s-60s, it was still widely held that that continents and ocean basins had fixed geographic positions. As such, scientists were reluctant to believe that continents could drift. - In the 1960s, the post-war boom in oceanography generated a lot of new data about the ocean floor. It turned out that the ocean floor was not as flat and featureless as they had originally thought. The ocean floor was characterized by deep depressions called **trenches** and a network of ridges that encircled the globe. These topographic data, together with heat flow measurements, led to the emergence of the Seafloor Spreading Hypothesis which revived interest in Alfred Wegener's idea of drifting continents. - **Pangaea** - an ancient Greek word meaning 'all land' or 'entire Earth'. - Alfred Wegener thought that continents drifted due to the tides formed by the gravitational forces of the moon and sun. He also believed that the larger and sturdier continents cut through the thinner oceanic crust, although there is no proof that the ocean floor is weak enough to allow passage of the continents without significantly deforming them in the process. ### THE EVIDENCES SUPPORTING CONTINENTAL DRIFT #### The fit of the continents: - Opponents of Wegener's idea disputed his continental fit evidence, arguing that the fit of the continents' margins was crude, and that shorelines were continuously being modified by wave erosion and depositional processes. - The oceanographic data later on revealed that a much better approach was to fit the continents together along the continental slope, where erosion would be minimal. In 1965, Sir Edward Bullard, an English geophysicist, and two of his associates demonstrated that the best fit between the continents occurs at a depth of approximately 2000 m. #### Similarity in geological units and structure #### Fossil match - ***Glossopteris flora*** -- 'seed fern' that grew only in a subpolar region, fossils of which were widely distributed over Australia, Africa, India, and South America - **Mesosaurus** - a freshwater reptile whose fossils were found only in black shales about 260 million years of age (Permian) in South Africa and Brazil. This land- based reptile could not have crossed the Atlantic Ocean. - **Lystrosaurus and Cynognathus** - land reptiles whose fossils were found across South America, Africa, India, and Antarctica. With their inability to swim and the continents' differing climates, the organisms must have lived side by side and that the lands drifted apart after they became extinct and fossilized. #### Glacial and paleoclimate evidence 4. **Paleomagnetism and polar wandering *Paleomagnetism*** - As magma cools down it starts forming minerals. Some minerals are strongly magnetic (e.g. magnetite). Below a certain threshold temperature, some of these minerals attain magnetic properties. The magnetic minerals start to align with the surrounding magnetic field. The alignment of these minerals becomes fixed once the lava or magma solidifies. Rocks therefore can potentially preserve or record magnetic polarity (normal vs. reverse), direction or location of magnetic poles, and the strength of the magnetic field. Deformation of the Earth's Crust: PLATE TECTONICS ------------------------------------------------- 1. **Seafloor bathymetry** -- *various methods of measuring ocean depths.* a. **Sounding line** -- weighted rope lowered overboard until it touched the ocean bottom; this old method is time-consuming and inaccurate b. **Echo sounding** -- type of sonar which measures depth by emitting a burst of high frequency sound and listening for the echo from the seafloor. Sound is emitted from a source on the ship and the returning echo is detected by a receiver on the ship. Deeper water means longer time for the echo to return to the receiver. c. **Satellite altimetry** -- profiles the shape of the sea surface by measuring the travel time of a radar pulse from the satellite to the ocean surface and back to the satellite receiver. The shape of the sea surface approximates the shape of the sea floor. #### Different features of the ocean floor  a. **Continental margin** -- submerged outer edge of the continent where continental crust transitions into oceanic crust. - **Passive or Atlantic type** -- features a wide, gently sloping continental shelf (50-200m depth), a steeper continental slope (3000-4000m depth), and a flatter continental rise. - **Active or Pacific type** -- characterized by a narrow shelf and slope that descends into a trench or trough. b. **Abyssal plains and abyssal hills** -- abyssal plain is an extremely flat, sediment covered stretches of the ocean floor, interrupted by occasional volcanoes, mostly extinct, called seamounts. Abyssal hills are elongate hills, typically 50-300m high and common on the slopes of mid oceanic ridge. (Note: figure above is not a very good representation of abyssal hill). These hills have their origins as faulted and tilted blocks of oceanic crust. a. **Mid-ocean ridges** -- a submarine mountain chain that wind for more than 65,000 km around the globe. It has a central rift valley and rugged topography on its flanks. Mid- ocean ridges are cut and offset at many places by transform faults. The trace of a transform fault may extend away from either side of the ridge as a fracture zone which is older and seismically inactive. b. **Deep-ocean trenches-** narrow, elongated depressions on the seafloor many of which are adjacent to arcs of island with active volcanoes; deepest features of the seafloor. c. **Seamounts and volcanic islands** -- submerged volcanoes are called seamounts while those that rise above the ocean surface are called volcanic islands. These features may be isolated or found in clusters or chains. #### Seafloor Spreading d. **Distribution of seafloor topographic features** -- distribution of mid-ocean ridges and depth of the seafloor e. **Sediment thickness** -- fine layer of sediment covering much of the seafloor becomes progressively thicker away from mid-ocean ridge axis; seafloor sediment not as thick as previously thought f. **Composition of oceanic crust** -- consists primarily of basalt g. High heat flow along mid-ocean ridge axes -- led scientists to speculate that magma is rising into the crust just below the mid-ocean ridge axis h. **Distribution of submarine earthquakes** -- earthquakes do not occur randomly but define distinct belts (earthquake belts follow trenches, mid-oceanic ridges, transform faults) a. #### Seafloor spreading hypothesis - In 1960, Harry Hess advanced the theory of seafloor spreading. Hess proposed that seafloor separates at mid-ocean ridges where new crust forms by upwelling magma. Newly formed oceanic crust moves laterally away from the ridge with the motion like that of a conveyor belt. Old oceanic crusts are dragged down at the trenches and re- incorporated back into the mantle. - The process is driven by mantle convection currents rising at the ridges and descending at the trenches. This idea is basically the same as that proposed by Arthur Holmes in 1920. b. #### Proof for seafloor spreading - **Magnetic stripes on the seafloor**: detailed mapping of magnetism recorded in rocks of the seafloor shows that these rocks recorded reversals in direction and strength of the Earth's magnetic field. Alternating high and low magnetic anomalies run parallel to mid ocean ridges. Pattern of magnetic anomalies also matches the pattern of magnetic reversal already known from studies of continental lava flows. - **Deep sea drilling results**: Age of seafloor forms a symmetric pattern across the mid- oceanic ridges, age increases with distance from the oceanic ridge; no seafloor older than 200 million years could be found, indicating that seafloor is constantly being created and destroyed. #### Theory of Plate Tectonics A. The Earth's outermost rigid layer (lithosphere)is broken into discrete plates each moving more or less as a unit. B. Driven by mantle convection, the lithospheric plates ride over the soft, ductile asthenosphere. C. Different types of relative motion and different types of lithosphere at plate boundaries create a distinctive set of geologic features. A. The lithosphere consists of the crust and the uppermost mantle. - Average thickness of continental lithosphere :150km - Average thickness of old oceanic lithosphere: 100km B. Composition of both continental and oceanic crusts affects their respective densities. C. The lithosphere floats on a soft, plastic layer called asthenosphere. D. Most plates contain both oceanic and continental crust; a few contain only oceanic crust. E. A plate is not the same as a continent. #### The driving forces for plate motion: A. Convection in the mantle (the sinking of denser material and rising of hot, less dense material) appears to drive plate motion. B. Gravity-driven mechanisms such as slab-pull and ridge-push are thought to be important in driving plate motion. Slab-pull develops when cold, dense sub ducting slab of lithosphere pulls along the rest of the plate behind it. Ridge-push develops as gravity pushes the lithosphere off the mid-ocean ridges and toward the subduction trenches. Three types of plate boundaries: -------------------------------- - Fossils are the remains or evidence of ancient life that have been turned to stone or fossilized. - Fossilization is a process by which the remains of ancient living things are turned to rock - Fossils give clues about the history of life on Earth, environments, climate, movement of plates, and other events - The fossil record shows us that present day life forms evolved from earlier different life forms. It shows us that the first organisms on Earth were simple bacteria that dominated the Earth for several billion years. - Scientists are able to arrange fossils according to age and this is called the fossil record. By studying the fossil record, scientists have found that the earth and its life forms have gone through many changes in the past. - Fossils have taught us how and when rock layers have formed. They have also helped the scientists to learn about life forms that have come and gone. - Fossils were used as markers when building up the geologic time scale. - Geologic time scale is a timeline that illustrates the Earth's past and serve as the "calendar" for events in Earth's history. - Geologic time scale describes the order of duration of major events on Earth for the last - Geologic time scale was developed after the scientist observed changes in the fossils and rocks going from oldest to youngest sedimentary rocks. - Eons is the largest division in the geologic time scale. The names of most of the eons and eras end in "zoic", because these time periods were recognized by the animal life present at the time. - Geologic time scale is usually presented in a chart like form with the oldest event at the bottom and the youngest at the top. - Geologic time scale was divided into four divisions which include the Eons, Era, Period, and Epoch. -- -- -- -- -- -- -- -- -- -- -- --  - **Eons -** The largest intervals of geologic time. A single eon covers a period of several hundred million years. The history of the Earth has been divided into three eons: Arhaean, Proterozoic and Phanerozoic. - **Archaean Eon** -- the period where life first formed on Earth, archea and bacteria. Earth cooled down and was able to support continents and oceans. - **Proterozoic Eon** -- the period just before the proliferation of complex life on Earth. There were extensive shallow epicontinental seas and rocks are less metamorphosed than Archean age. - **Phanerozoic Eon** -- this is the period of visible life where rapid expansion and evolution of life forms occur and fill the various ecological niches available on Earth. - **Era -** It is the subdivision of eons. The geologic time scale is divided into three eras -- Paleozoic (time of ancient life), the Mesozoic (time of middle life) and the Cenozoic (time of recent life). -- -- -- -- -- -- - **Periods and Epochs -** Each era is further divided into periods and further divided into epochs. - **Cambrian Period -** Almost all marine organisms came into existence as evidenced by abundant fossils. - **Ordovician Period -** This period marks the earliest appearance of vertebrates and the jawless fish known as Agnatha. - **Silurian Period -** This period brought the emergence of terrestrial life, the earliest well developed circulatory system (vascular plants) known as Cooksonia. - **Devonian Period -** This period known as the "age of fishes". Lowland forests of seed ferns, scale trees and true ferns flourished. Sharks and bony fishes developed. - **Carboniferous Period** - Warm, moist climate conditions contributed to lash vegetation and dense swampy forests. Insects under rapid evolution led to such diverse forms of giant cockroaches and dragonflies. - **Permian Period -** A dramatic climatic shift may have been partially triggered the assembly of smaller continents into a supercontinent, Pangea which was surrounded by an immense ocean called Panthalassa. The reptiles were well-suited to their environment that they ruled the Earth for 200 million years. The two major groups of reptiles -- diapsids and synapsids dominated this period. Diapsids gave rise to the dinosaurs while synapsids gave rise to mammals. - **The Mesozoic Era -** Known as the age of reptiles, it is made up of three periods: Triasic, Jurassic and Creataceous. The most significant event was the rise of the dinosaurs. A famous Jurassic deposit is the Morrison Formation, within which the world's richest storehouse of dinosaurs was preserved. True pines and red woods appeared and rapidly spread. Flowering plants arose and their emergence accelerated the evolution of insects. A major event of this era was the breakup of Pangea. At the end of this era, the dinosaurs and reptiles were completely wiped out. - **The Cenozoic Era -** This era is known as the **"age of mammals"** because mammals replaced the reptiles as the dominant land animal. It is also sometimes called the **"age of flowering plants"** because angiosperms replaced gymnosperms as the dominant land plants. This era is made up of two periods: Tertiary and Quartenary. From oldest to youngest the periods are broken up into the Paleocene, Eocene, Oligocene, Miocene and Pliocene for the Tertiary period and the Pleistocene and Holocene for the Quarternary period.  Geologic Processes and Hazards ============================== #### How do geological processes occur? #### How about Geologic Hazards? -- ------------------------------------------- -- A. Tephra falls and ballistic projectiles B. Pyroclastic phenomena C. Lahars (mud flows) and floods D. Lava flows and domes E. Poisonous gases -- ------------------------------------------- -- A. **Ground shaking** is one of the hazards resulting from earthquake, volcanic eruption, and landslides. Ground shaking is both a hazard created by earthquakes and the trigger for other hazards such as liquefaction and landslides. Ground shaking describes the vibration of the ground during an earthquake. B. **Surface faulting** is displacement that reaches the earth\'s surface during slip along a fault. It commonly occurs with shallow earthquakes; those with an epicenter less than 20 km. Surface faulting also may accompany aseismic creep or natural or man-induced subsidence. C. A **landslide** is defined as the movement of a mass of rock, debris, or earth down a slope. Landslides are a type of \"mass wasting,\" which denotes any down-slope movement of soil and rock under the direct influence of gravity. The term \"landslide\" encompasses five modes of slope movement: falls, topples, slides, spreads, and flows. D. **Liquefaction** describes the way in which soil liquefies during ground shaking. Liquefaction can undermine the foundations and supports of buildings, bridges, pipelines, and roads, causing them to sink into the ground, collapse, or dissolve. E. **Tsunamis** are giant waves caused by earthquakes or volcanic eruptions under the sea. It can injure or kill many people and cause significant damage to buildings and other structures. The speed of tsunami waves depends on ocean depth rather than the distance from the source of the wave. Tsunami waves may travel as fast as jet planes over deep waters, only slowing down when reaching shallow waters. A. **Tephra** consists of pyroclastic fragments of any size and origin. It is a synonym for \"pyroclastic material.\" Tephra ranges in size from ash (\64 mm). B. A **pyroclastic flow** is a dense, fast-moving flow of solidified lava pieces, volcanic ash, and hot gases. Pyroclastic flows form in various ways. A common cause is when the column of lava, ash, and gases expelled from a volcano during an eruption loses its upward momentum and falls back to the ground. Another cause is when volcanic material expelled during an eruption immediately begins moving down the sides of the volcano. Pyroclastic flows can also form when a lava dome or lava flow becomes too steep and collapses. C. **Lahar** is an Indonesian term that describes a hot or cold mixture of water and rock fragments that flows down the slopes of a volcano and typically enters a river valley. Lahars are extremely dangerous especially to those living in valley areas near a volcano. Lahars can bury and destroy manmade structures including roads and bridges. D. A **flood** is an overflow of water that submerges land that is usually dry. Floods can look very different because flooding covers anything from a few inches of water to several feet. E. **Lava** domes are formed by viscous magma being erupted effusively onto the surface and then piling up around the vent. Like lava flows, they typically do not have enough gas or pressure to erupt explosively, although they may sometimes be preceded or followed by explosive activity. The shape and size of lava domes varies greatly, but they are typically steep-sided and thick. F. **Poisonous gases**, the gases that are released during a volcanic eruption, come from deep within the Earth. The largest portion of gases released into the atmosphere is water vapor. Geologic Process ---------------- Hazards ------- Hazard Map ---------- #### Geologic Processes and Hazards (LANDSLIDES) 1. Overloading slopes 2. Mining which uses explosives underground 3. Excavation or displacement of rocks. 4. Land use such as modification of slopes by construction of roads, railways, buildings, houses. 5. Quarrying which includes excavation or pit, open to the air, from which building stone, slate, or the like is obtained by cutting, blasting, etc. 6. Land pollution which is the degradation of earth's land surface, exploitation of minerals and improper use of soil by inadequate agricultural practices. 7. Excavation which pertains to exposure, processing, and recording of archaeological remains 8. Cutting Trees that can lead to deforestation and may encourage landslide 1. Stay alert and awake. Many debris-flow fatalities occur when people are sleeping. 2. If you are in areas susceptible to landslides and debris flows, consider leaving if it is safe to do so. 3. Listen for any unusual sounds that might indicate moving debris, such as trees cracking or boulders knocking together. 4. If you are near a stream or channel, be alert for any sudden increase or decrease in water flow and for a change from clear to muddy water. 5. Be especially alert when driving. Bridges may be washed out, and culverts overtop. 6. Be aware that strong shaking from earthquakes can induce or intensify the effects of landslides. Hydrometeorological Phenomena and Hazards ========================================= #### Hydrometeorological hazards #### Tropical cyclones #### Monsoons 1. **Amihan:** brings cloudless skies and nippy mornings during the dry season (October to late March) 2. **Habagat:** brings heavy rains and some deadly typhoons (June to September) #### Floods Marine and Coastal Processes ============================ - The coast is one of the most dynamic parts of the Earth's surface. It contains some of the world's sensitive and threatened ecosystems such as mangroves and beach forest, seagrass and coral reefs. The dynamics of the marine environment result to different processes that affect human communities and organisms in the coastal ecosystem. Some of these processes result to natural hazards. - Marine systems are referred to as the world's oceans while coastal systems refer to the interface between oceans and land, extending seawards to about the middle of the continental shelf and inland to include all areas strongly influenced by the oceans (Millennium Ecosystem Assessment, 2005). About 23% of the world's population live within 100 km of the coast and about 10% live in extremely low-lying areas. Many of these processes like coastal erosion, storm surges, coastal flooding, and tsunami. Revisiting Marine and Coastal Processes --------------------------------------- Effects of Marine and Coastal Processes ---------------------------------------  #### Coastal Erosion #### Saltwater Intrusion #### Submersion 2^ND^ SEMESTER (2^ND^ Quarter) ### BIOENERGETICS: UTILIZATION OF ENERGY #### Definition of terms - Living cells require energy from outside sources. - Some animals, such as the chimpanzee, obtain energy by eating plants, and some animals feed on other organisms that eat plants. - Energy flows into an ecosystem as sunlight and leaves as heat. - Photosynthesis generates O2 and organic molecules, which are used in cellular respiration. - Cells use chemical energy stored in organic molecules to regenerate ATP, which powers work. - **Cellular respiration** includes both aerobic and anaerobic but is often used to refer to aerobic respiration. - **AEROBIC RESPIRATION** consumed organic molecules and O2 and yields ATP. - Anaerobic respiration is similar to aerobic respiration but consumes compounds other than O2. ### EQUATION OF CELLULAR RESPIRATION: #### Principle of Redox Process - During cellular respiration, the fuel (such as glucose (C6H12O6) is *[oxidized,]* and O2 is reduced. ### THE STAGES OF CELLULAR RESPIRATION 1. **Glycolysis** is the breakdown of glucose to pyruvate where small amounts of ATP are produced. This process occurs in the *[cytoplasm]* of the cell. 2. **The Citric Acid Cycle or Krebs Cycle** degrades pyruvate to carbon dioxide, water, ATP and reducing power in the form of NADH, H+. This stage happens in the [matrix of the] [mitochondria.]  3. **Oxidative Phosphorylation** which includes electron transport chain and chemiosmosis generates high amount of ATP, because it is powered by redox reaction. This stage occurs in the [inner membrane of the mitochondria.] ### SUMMARY (DIAGRAM) OF CELLULAR RESPIRATION - **Fermentation** consists of glycolysis plus reactions that regenerate NAD+, which can be reused by glycolysis. #### Two Common Types are: 1. **ALCOHOL FERMENTATION --** pyruvate is converted to ethanol in two steps, with the first releasing CO2. - alcohol fermentation by yeast us used in brewing, winemaking, and baking. 2. **LACTIC ACID FERMENTATION --** pyruvate is reduced to NADH, forming lactate as an end product, with no releasing of CO2. - lactic acid fermentation by some fungi and bacteria is used to make cheese and yogurt. - Human muscle cells use lactic acid fermentation to generate ATP when O2 is scarce. Perpetuation of Life (Asexual and Sexual Reproduction, Parts of a Flower) ------------------------------------------------------------------------- - **Sexual reproduction** involves the union of gametes (egg cell and sperm cell) through fertilization. Meanwhile, - **Asexual reproduction** involves the creation of cloned offspring from a parent organism. - **Asexual Reproduction in plants**, flowers play a major role in sexual reproduction as it houses the structures for this process.  #### "Main Flower Organs" 1. **Stamen** -- The stamen is male reproductive organ, which produces the pollen, which contains the sperm cell. 2. **Carpel** (Reproductive) 3. #### Petals 4. **Sepals** (Sterile) - These organs are held by a structure called a **receptacle.** Meanwhile, the carpel or the female reproductive organ has the following structures: - ***Stigma*** -- is the sticky end of the carpel where pollen is trapped during the process of pollination - ***Style*** -- the style is a slender neck where the sperm cell from the pollen can travel to the base of the carpel called the *ovary.* - ***Ovary*** -- In the ovary are **ovules**, female gametes, which when is fertilized by the sperm becomes the seeds of a **fruit**. Sometimes, a flower has only one carpel, or has more than one carpel, which is fused, it is called a **pistil**. - **Pollination** is the process of transferring pollen from an anther to a stigma. - There are various ways in which pollination occurs whether through - Pollination is needed in order for fertilization to occur. Compared to self-pollination, cross-pollination can increase genetic diversity of plants as genes from two different individuals are shared by the offspring. - There are different methods on how pollen is transferred from one anther to one stigma. Mainly, pollination is through - **Biotic** means (80%) and among abiotic methods of pollination, - Wind (98%) and Water (2%) are the main agents. #### "Biotic Pollinators" 1. **Bees** -- rely on nectars from flowers for they food, as such they pollinate flowers with delicate, sweet fragrance. They are also attracted to bright colors, yellow and blue. 2. **Moths and butterflies** -- like bees, detect odors and pollinate flowers with sweet fragrance. The difference in activity of a butterfly and a moth allows pollination of different plants, as butterflies are attracted to bright flowers, they are day pollinators while moths, which are mostly active at night, are attracted to white or yellow flowers which are very distinct at night. 3. **Bats** -- like moths are attracted to sweet smelling lightly colored flowers which stand out at night. 4. **Flies** -- are attracted to red, fleshy flowers with a rank odor reminiscent of decaying meat. i. 5. **Birds** -- do not have a keen sense of smell, thus, flower fragrance is not a flower character trait by plants pollinated by birds. Birds are usually attracted to bright flowers such as red and yellow. Also, their nectar has high sugar content which is needed by birds. There are other biotic agents of pollination, which aids in the delivery of pollen to a flower's carpel. - This organism, as shown above, is adapted to the various characteristics of flowers that require pollination. After the process of pollination, the process of fertilization might occur, which can result in the development of a seed which houses the embryo of a future plant. - Below is the process of **gametophyte production**, **pollination**, **double fertilization and seed development**. - **ASEXUAL REPRODUCTION** in plants, as some organs grow indeterminately due to tissues that can actively divide (meristem- actively dividing cells) and revert to non- specialized structures (parenchyma tissues). - This indeterminate growth can lead to a form of reproduction called asexual reproduction, as these organs can separate from the parent plant with the ability to grow and develop. - Fragmentation, the most common method of asexual reproduction, can occur through growth from a stem, leaf, root and other plant organ which gained the ability comparable to parent plant. - Not all asexual reproduction is a product of fragmentation, plants can also produce seeds without the process of pollination and fertilization, called **apomixis**. - **Apomixis** occurs when diploid cells in the ovule creates an embryo, this can later result in the formation of a seed. - Furthermore, vegetative propagation and grafting are natural and man-made processes of asexual reproduction. - ##### "Different Types of Vegetative Propagation" a. **Stems**: that grow horizontally above the ground is called a runner. The nodes of these plants can allow asexual reproduction through bud growth. - Ex. Grass b. **Roots**: swollen roots called tubers can allow asexual reproduction. - Ex. swollen root of a cassava, not that of a potato. Potatoes are stems, as evidenced of their nodes. c. **Leaves**: that are succulent, such as the catacataca leaf, can allow asexual reproduction. d. **Bulbs:** such as onion (each skin is a leaf) and garlic (each piece is a modified stem and leaf) is attached to an underground stem. Each can form a new bulb underground. - ##### "Artificial propagation" a. **Grafting:** is composed of the stock (rooted part of the plant) and the scion (the attached part). This is usually done to hasten the reproductive ability of a plant, grow a selected fruiting plant, etc. b. **Layering:** like what happens to a runner, wherein, a shoot of a parent plant is bent and is covered by soil. This stimulates root growth, after which, the plants can be separated. c. **Cutting:** is done to propagate a plant by cutting the stem at an angle of a shoot with attached leaves. Sometimes, growth stimulator is given. - Below is the picture of a flower and the structures involved directly/ indirectly in sexual reproduction: - #### Vegetative Part a. **Receptacle** -- holds the floral parts of the flower. b. **Sepal** -- modified leaves that protects a flower in bud and holds the petals when in bloom. c. **Calyx** -- collective term for the sepals. d. **Petal** -- modified leaves that surround the reproductive organ or plants; normally colorful, and with odor, to attract pollinators e. **Corolla** -- collective term for petals f. **Inflorescence** -- cluster of flowers - #### Reproductive Part g. **Stamen** -- male reproductive organ h. **Filament** -- stalk that holds the anther at the end i. **Anther** -- produces the pollen which houses the sperm cell j. **Carpel** -- Female reproductive organ. Singly or fused, is called a pistil k. **Style** -- the slender neck of the carpel which holds the stigma at its end. l. **Stigma** -- is a structure with sticky substance which traps pollen. m. **Ovary** -- the bulbous structure of the carpel which contains the ovule n. **Ovule** -- has the egg cell of the plant. - #### Complete vs Incomplete Flower o. A complete flower has all the parts described. p. An incomplete flower is missing one or more parts. - #### Adaptive mechanisms q. As the flower is important in the development of a fruit and the eventual dispersal of the seed for plant propagation, it has evolved different adaptive mechanisms. r. This structure to function relationship is important as the plant should be able to attract specific pollinators to increasing the success rate of its propagation. s. Competition among plants over one pollinator may result in lesser chance of propagation. ### FRUITS a. The ovary walls eventually become the pericarp during development. - Pericarp-the walls of a ripened ovary/fruit - Parts of a Fruit 1. **Exocarp**- outer skin of the fruit. 2. **Mesocarp**- fleshy middle layer of the pericarp of a fruit. Part of a fruit that can be eaten. 3. **Endocarp**- inside layer of the pericarp which directly surrounds the seeds. b. Depending on fruit adaptations, the pericarp can be stony, woody, fleshy as such the endocarp might not be fleshy, the exocarp might be rubbery or woody, etc. For example: the apple's seed and fruit are protected by an accessory fruit which formed from the fleshy receptacle. ### SEEDS a. The seed or mature ovules contain the embryo, which will eventually germinate and grow if properly dispersed in a favorable environment. b. To protect the embryo from harsh environmental conditions, it goes into a state of dormancy until a period for favorable growth and development arrives. The embryo, which is not able to produce its own food, yet, is provided with food by the cotyledon or the endosperm, or both. c. To protect the embryo, the seed coat has a hardened outer covering which protects it from physical or chemical disturbances. d. Parts of a Seed 1. **Testa-** outer coat of the seed that protects the embryonic plant. 2. **Microphyle**- it is a tiny pore in the testa and permits water to enter the embryo before active germination. 3. **Cotyledon**- contains high quantities of starch and will provide a source of food. 4. **Epicotyl**- is the embryonic shoot above the cotyledon that will eventually develop into the leaves of the plant. 5. **Hypocotyl**- connection between cotyledon and radicle. Pushes the cotyledons above the ground to develop. 6. **Radicle**- this is the embryonic root which will develop into the primary root of the plant.  e. In grass, the embryo is protected by two sheaths: the coleoptile (protects the young shoots) and coleorhiza (protects the young roots). ### SEED AND FRUIT DISPERSAL 1. Like pollination in plants, different agents aid seed and fruit dispersal. a. Abiotic agents (wind, water) b. Biotic agents (animals) 2. In order to propagate, plants have evolved in order to adapt to their environments. c. Flowers ensure the formation of the embryo through different adaptations for pollination and fertilization. d. The developing embryo is helped by the adaptation of the fruit and seeds, which further protects and aids in its propagation. Perpetuation of Life (Plants and Animal Reproduction) ===================================================== - **Sexual reproduction** is the process of joining the haploid gametes (sex cells) to form a diploid cell called a zygote. - A zygote, eventually becomes an embryo and later on develop into an organism. - The female gamete is an egg cell, is usually non-motile, to ensure survival of the embryo by storing energy. - The male gamete is a sperm cell, which is motile to search for the egg cell for fertilization. - **Asexual reproduction**- fusion of the egg cell and sperm cell does not occur; reproduction is mainly through mitosis which creates a clone of the parent. #### "The following are the different methods of asexual reproduction: 1. **Budding**- occurs when individuals arise throughout the outgrowths from a parent. This can create a colony of individuals attached to a parent, such as in corals. 2. **Fission-** is the separation/division of an organism to form individuals of approximately same size. This is usually observed in animal-like protists.  3. **Fragmentation and Regeneration-** fragmentation is when an animal's body breaks into different parts, which later regenerate to form several individuals. Sponges, annelids, cnidarians and tunicates are examples of this mode of reproduction. 4. **Parthenogenesis**- is like apomixes in plants, where the egg cell develops without fertilization. This is exhibited by bees, wasps, lizards, sharks.  ### "GENETIC ENGINEERING" #### Example Process of Genetic Engineering 1. Genetic information is inserted via a vector. The small replicating molecule is called a DNA vector (carrier).The most commonly used vectors are [[plasmids]](https://www.britannica.com/science/plasmid)(circular DNA molecules that originated from [[bacteria]](https://www.britannica.com/science/bacteria)), [[viruses]](https://www.britannica.com/science/virus), and [[yeast]](https://www.britannica.com/science/yeast-fungus) cell. A specific target genetic segment is spliced into a bacterial plasmid. The resulting molecule is called recombinant DNA. It is recombinant in the sense that it is composed of DNA from two different sources. (Diagram on the right shows the process in creating a recombinant DNA molecule) 2. Recombinant DNA (plasmid) put into a bacterial cell and allowed to be replicated. 3. This gene can then be transferred to a target organism, such in the case of pest-resistant crop, or proteins can be harnessed, such as in the case of insulin. (sample illustration on the next page) 1. **What are the positive impacts of GMOs?** 2. **What are the negative impacts of GMOs?**  3. **Is there a biological reason in resisting the use of GMO?** #### What are possible reasons not to allow GMOs in a country? #### As a country with a history of economic, political, psychological dependence and subservience to other countries, do you think the use of GMO will be more beneficial or detrimental? #### Barring biological use of GMOs, how is the use of GMO in the country a symptom of political and economic dependency to other countries? #### How can the benefits of GMOs outweigh its negative effects? How Animal Survive (Nutrition) ============================== - In **ingestion**, or process of taking in food substances, the animal takes in food in different ways. Microscopic animals, for instance, can use special cavities which can allow entrance of food or they can use phagocytosis or pinocytosis wherein food particles are engulfed, thus, creating a food vacuole. A. **Filter feeding**- uses adaptation in feeding food particles from the environment, which is usually aquatic. Examples of these are clams, mussels, whales, etc. B. **Substrate feeding**- animals live in or on their food source. Examples of this are the leaf miner, maggots and other parasites. C. **Fluid feeding**- animals suck nutrient-rich fluid from a host or a source. They have different adaptations in order to get food such as the proboscis of mosquitoes, the long tongue of nectar-feeding bats and long beaks of hummingbirds. D. **Bulk feeding**- animals, such as us humans, take in large particle sized food. Different animals have acquired different adaptations such as tentacles, claws, venomous fangs, large mandible and teeth which aids in killing prey or tearing off pieces of meat or vegetation - **Digestion** of food involves either intracellular digestion or extracellular digestion or both processes. Digestion can either be mechanical or chemical. **Mechanical digestion** aids in physically breaking down food particles for easier chemical digestion. **Chemical digestion** is the process of breaking down complex molecules into simpler molecules through chemical hydrolysis. - **Absorption** allows the animals to acquire the necessary energy, organic molecules and essential nutrients from the digested food. Chemical energy comes from the breakdown of ATP which comes from sources such as sugars from carbohydrates. Organic molecules can serve as the organic building blocks of the body where muscles, connective tissues, nerve tissues are built. These organic molecules are the biomolecules that we acquire from food: carbohydrate, protein, fats and nucleic acids. Carbohydrates are important for instant energy, but if not used will be stored and can turn into fats. Proteins, which are made up of amino acids, are the building blocks of different structures in the organism, e.g. muscles, cells, antibodies, etc. Fats are great source of energy as they can store a lot of energy. Nucleic acids are important for building blocks of genetic information. Essential nutrients are substances which the animal's own body cannot synthesize, thus, come from the food source. Essential amino acids, essential fatty acids, vitamins and minerals are examples of essential nutrients. - As food is only partially digested, not all particles are absorbed by the body. The semi- digested food, which in turn becomes waste is then **eliminated** or digested. In some animals, such as humans, water is first reabsorbed before it is eliminated or egested out of the body. Different symbiotic relationships are present in order to fully utilized the substances present in waste (feces) before it is finally released. ### THE HUMAN DIGESTIVE SYSTEM HOW ANIMAL SURVIVE (CIRCULATION AND GAS EXCHANGE) ------------------------------------------------- #### "Circulation and Gas Exchange" The Circulatory System - In an **open circulatory system**, blood is not fully enclosed in a vessel and is pumped out of the system via an exit called an ostium to a space which surrounds tissues called a sinus. When the heart contracts, the circulatory fluid goes out of the system, if the heart relaxes the fluid returns. As the blood goes directly to the tissues, it mixes with the interstitial fluid which surrounds tissue and cells and is called a **hemolymph**. - In animals with **closed circulatory system**, the circulatory fluid does not go out of the vessel. Exchange occurs through diffusion via thinner vessels called capillaries across the interstitial fluid. ### STRUCTURES 1. **Atrium**- receives blood 2. **Ventricle**- pumps blood 3. **Artery**- transports blood away from the heart, muscular 4. **Vein**- transports blood back to the heart, has valves and thinner in structure 5. **Capillary**- exchange of substances, has very thin walls 6. **Venule**- small vein 7. **Arteriole**- small artery a. The **pulse** is the wavelike force which is a result of the pumping of blood through an artery with decreasing diameter. As the diameter of the artery decreases, the walls of the artery stretch to accommodate the blood that is passing through it. b. The **heart** has the ability to produce its own electrical signal to stimulate the contraction of the heart muscles. Thus, the heart is independent from the brain; the brain only affects the rate of heart contraction but not starts the contraction of the heart. The cardiac cycle is the complete cycle of contraction and relaxation, together with the intervening phase. c. **Systole**- is the contraction phase of the cardiac cycle d. **Diastole** -- is the relaxation phase of the cardiac cycle ### GAS EXCHANGE ### THE TRACHEAL SYSTEM OF INSECTS ### TERRESTRIAL VENTILATION ### GAS EXCHANGE AND THE CIRCULATORY SYSTEM ### HOW ANIMALS SURVIVE (HOMEOSTASIS AND WASTE REMOVAL) - **Excretion** is the process of removing wastes and excess water from the body. It is one of the major ways the body maintains homeostasis. Organs of excret