Chapter 1, 2 & 3 for 4th Class PDF

BAGHDAD COLLEGE Dr. JASIM MOHAMMED ALOBAIDI BIOLOGY CLASS 4th CHAPTER 1 / Classification of living organisms Observational classification: organisms...

BAGHDAD COLLEGE Dr. JASIM MOHAMMED ALOBAIDI BIOLOGY CLASS 4th CHAPTER 1 / Classification of living organisms Observational classification: organisms classifying into smaller groups is necessary to acquire sufficient information about organisms. History of Classification Q/ Explain the classification of Aristotle. A/ 1- The Greek philosopher Aristotle (350 BC):  Listed only a few hundred plants and animals.  Plants classify as grasses, bushes, or trees.  Animals classify as aquatic or terrestrial. Empiric (Artificial) classification: This classification of organisms is based on appearance and similarities in function. NOTE/ Initially, organisms were classified as plants (motionless organisms) or animals. NOTE/ Microorganisms are discovered in the 16th century, like bacteria, blue-green algae and euglena. Q/ Explain the analogous organ with an example. A/ Analogous Organs: These organs generally similar in shape and function, but these organs are embryologically different. For instance, wings in butterflies or birds provide flight; therefore we say that butterfies and birds aren’t related. Q/ Explain the homologous organ with an example. A/ Homologous Organs: These organs sharing the same origin and similar embryological stages, but functions of homologous organs may be the same or different, For instance, a human’s arm seems quite different from a bat’s wing. NOTE/ Homologous organs are the basis of modern classification. 2- John Ray (1626-1705):  Tried to unify classification systems.  He was the first to use the term “species”. 3- Carl Von Linneaus:  He is the founder of modern systematics.  He applied his binominal nomenclature method to plants (in 1753) and to animals (1758) in his book Systeme Naturae. BAGHDAD COLLEGE Dr. JASIM MOHAMMED ALOBAIDI BIOLOGY CLASS 4th Homologous organs in different organisms System of Classification NOTE/ Phylogenetic systematics used today depends on Linnaeus systematics and homology. NOTE/ The basis of modern systematics is the grouping of organisms according to similarities. NOTE/ Classification of organisms is used the following criteria: origins, relatedness, developmental stages. NOTE/ in the binomial system created by Linnaeus, (species is the basic unit of nomenclature). A species: is a group of organisms from the same population sharing the same embryological, morphological, and physiological features, and are capable of giving birth to fertile offspring when mated under natural conditions. There are two points in Linnaeus’ hypothesis:  There is an ideal type for each species. This ideal type: represents the standard features of every single individual of the species.  The number of species and their types is constant and unchangeable. Q/ Explain how Linnaeus named organisms with an example. A/ 1- According to systematic of Linnaus, a species is named with two names. 2- First is the genus name with the first letter capitalized. 3- Second is the species name with the first letter is not capitalized. 4- Both these names are written in italics and in Latin. 5- The reason for this is to have a single name in the scientific world, thus simplifying the study of species. BAGHDAD COLLEGE Dr. JASIM MOHAMMED ALOBAIDI BIOLOGY CLASS 4th 6- For example, Canis familiaris is the name for dogs. Canis lupus is the wolf.  The first name (Canis) shows that these two species are in the same genus. Genus: A group of species similar in some characteristics. Family: similar genera. Order: similar families. Class: similar orders. Phylum: similar classes. Kingdom: Similar phyla. NOTE/ Species level have the largest number of common features and the least number of individuals compared to the higher levels. NOTE/ Kingdoms have the fewest common characteristics and the highest number of individuals. BAGHDAD COLLEGE Dr. JASIM MOHAMMED ALOBAIDI BIOLOGY CLASS 4th CHAPTER 2 / ECOLOGY The Scope of Ecology Ecology: (from the Greek oikos, “home,” and logos, “to study”) is a branch of science that studies the interactions of living things with each other and with the environment. Q/ why today environmental problems have increased? (Or) Why ecology is taught as a science in schools? A/ Due to development in technology and industry, and because of the unwitting actions of people. For example,  The overuse of chemical substances contaminates the water and causes slow-progressing diseases in humans.  The inefficient use of soil depletes water sources and makes the soil arid. NOTE/ the levels between organisms and biosphere are included in ecology: protoplasm - cells - tissues - organs - organ systems - organisms - population - community - ecosystem – biosphere - earth - planets - solar system - galaxies – cosmos. Terms used in Ecology Ecosystem: A community together with the abiotic environment forms an ecosystem. Environment: is the place where an organism lives, The environment includes abiotic components (nonliving chemical and physical factors) such as temperature, light, water, and nutrients and biotic components (living) such as plants, animals, fungi-all the other organisms. Organismal (Individual) Ecology: A branch of ecology that studies the relationship of an individual or individuals of a species to the environment. Population ecology: The next level of organization in ecology is the population. Population: (is the smallest unit of ecology) a group of individuals of the same species living in (the same area) a particular geographic area. Q/ one population are not self-sufficient. A/ A population exists as long as it lives together with other populations and maintains its relations. Community: A group of populations living together in the same area, with abiotic factors included. Communities are self-sufficient. Q/ What is the difference between population and community? A/ 1- Population is the smallest unit of ecology, but community is bigger from population in ecology. BAGHDAD COLLEGE Dr. JASIM MOHAMMED ALOBAIDI BIOLOGY CLASS 4th 2- Population is a group of individuals of the same species living in the same area, but community is a group of populations living together in the same area. 3- One population is not self-sufficient, but Communities are self-sufficient. Biosphere: All of the places where organisms can live, from the bottom of the ocean to an altitude of 10,000 m. Habitat: The natural environment or place where an organism, population, or species lives. For instance:  Habitat of paramecium is fresh water.  Habitat of certain kind of ants is trees in the forest. Biome: The geographical area of the environment that an organism needs to live (the place where the community lives). Biomass: The dry weight of organic matter comprising a group of organisms in a particular habitat. Flora: The plant or bacterial populations living in a particular environment. Fauna: The animal populations living in a particular environment. Interaction: is a key idea in ecology. Q/ No organism are completely self-sufficient. A/ Organisms depend upon other organisms and upon the environment for survival. For example autotrophs produce food and oxygen and heterotrophs produce carbon dioxide, which is needed for autotrophs to produce food. Branches of Ecology  Global ecology.  Ecosystem ecology.  Community ecology.  Population ecology.  Physiological ecology. Ecosystem components An ecosystem (environment): is all the living and nonliving factors that surround an organism. The ecosystem includes: A- Biotic components 1. Producers: autotrophic organisms which can produce their own food. In terrestrial ecosystems, the dominant producers are green plants, while in fresh water and saltwater ecosystems, the dominant producers are algae (a kind of protist). BAGHDAD COLLEGE Dr. JASIM MOHAMMED ALOBAIDI BIOLOGY CLASS 4th 2. Consumers: are heterotrophic organisms that cannot produce their own food. Q/ List types of consumer can be identified according to their food source. A/ There are four types of consumer can be identified according to their food source.  Herbivores (also called primary consumers), such as sheep, eat plants directly.  Carnivores (secondary or tertiary consumers), such as lions, feed on other animals.  Omnivores, such as humans, feed on both plants and animals.  Decomposers are (organisms of decay): They break down detritus (nonliving organic matter) to inorganic matter which can be used again by producers. In this way materials are constantly recycled in an ecosystem. Q/ Decomposers are contributing constantly recycled of materials in an ecosystem. A/ they break down detritus (nonliving organic matter) to inorganic matter which can be used again by producers. B- A biotic Components:  Minerals:  It can be solid that form the soil.  It contains all elements and chemical compounds which are necessary for life maintenance.  Organic and non-organic materials are main components of soil.  Water:  It forms the biggest part in the ecosystem, such as: rivers, lakes and oceans.  Water is the habitat for many solvent minerals and chemicals. Q/ Water basically are the most important life source. A/ due to its percentage in living cell (more than 90% in some cells kinds).  Gases: Q/ What is the importance of gasses in ecosystem? A/ Take an important role in ecosystem, represented by  A mixture of different gasses that forms biosphere.  Mainly this mixture is formed by Nitrogen, Oxygen, CO2, water vapor and other gasses.  Although all of these gasses are important but, oxygen is the most important base that forms any ecosystem. BAGHDAD COLLEGE Dr. JASIM MOHAMMED ALOBAIDI BIOLOGY CLASS 4th  Solar energy: Q/ Solar energy clearly affect the ecosystem. (Or) Solar energy affects the density of living organism's numbers from one habitat to another. A/ this effect appears in different forms due to alternation of earth position around the sun and four season's sequence. BAGHDAD COLLEGE Dr. JASIM MOHAMMED ALOBAIDI BIOLOGY CLASS 4th CHAPTER 3 / Food chain and elements cycles The Interactions of Life Nutrition: One of the properties that distinguish living things from nonliving things. Organisms feed and acquire materials necessary for energy production, regulation and assembly. Q/ Classify the organisms according to their feeding styles. A/ 1- Autotrophic organisms:  Photosynthetic autotrophs.  Chemosynthetic autotrophs. 2- Auto-heterotrophic organisms. 3- Heterotrophic organisms:  Holozoic nutrition (Heterotrophic).  Carnivores (meat eaters).  Herbivores (plant eaters).  Omnivores (plant and meat eaters). 1- Autotrophic organisms (Autotrophs): These organisms produce their own food from inorganic substances; autotrophs are either photosynthetic or chemosynthetic. Q/ Compare between photosynthetic or chemosynthetic organisms. Photosynthetic organisms Chemosynthetic organisms These organisms produce organic molecules from Some bacteria oxidize inorganic substances and inorganic molecules. release energy ATP is used in the production of organic substances. Using sunlight energy (photosynthesis). Since chemicals are used in place of light (chemosynthesis). EX: Green plants, algae, and blue-green bacteria. EX: Nitrite and nitrate bacteria. These organisms which release O2. These organisms which don’t release O2. NOTE/ Some bacteria use hydrogen sulfide (H2S) or hydrogen (H) instead of water. The bacteria using these don’t release O2. 2- Auto-heterotrophic organisms:  Some unicellular (e.g. Euglena):  Carry chloroplast and practice photosynthesis.  These organisms carry out photosynthesis in the presence of light (autotrophs). BAGHDAD COLLEGE Dr. JASIM MOHAMMED ALOBAIDI BIOLOGY CLASS 4th  While at night they obtain food from their surroundings (heterotrophs).  Insectivorous plants (Insect eaters) :  Have chloroplasts like green plants and carry out photosynthesis.  At the same time, since these plants live in nitrogen-deficient soil, they obtain nitrogen by eating insects.  That attracts insects with their color and aroma.  They secrete enzymes to digest insect proteins.  The amino acids released are absorbed into the cells and used in metabolism.  Examples include Dionea, Drosera and Nepentes plants. Give a reason: Q/ Euglena is autotrophic while sometimes which heterotrophic organisms. A/ Euglena are carry chloroplast, and these organisms carry out photosynthesis in the presence of light (autotrophs), while at night they obtain food from their surroundings (heterotrophs). Q/ Insect eaters are therefore highly advances plants quite different from other plant types. A / These plant lives in areas where there is a lack of nutrients in the soil or very poor conditions where roots do not survive well. The plants have adapted their leaves into insect catchers that can hold down an insect and digest the internal juices. 3- Heterotrophic organisms: Animals, fungi, some bacteria and protists can’t synthesize their own food and get it from other organisms or decaying matter. Q/ Classify are heterotrophs according to their habitat and food type used. 1- Holozoic nutrition (Heterotrophic): This is the form of nutrition used by most animals and involves the ingestion of complex food, which is broken down into simpler molecules before being absorbed. 2- Carnivores (meat eaters):  They eat only meat.  Have well-developed incisor and canine teeth.  Have Single-lobed stomachs.  And have shorter intestines.  Examples are lion, tiger, wolf and etc. 3- Herbivores (plant eaters):  They eat only plant.  Have well-developed molar teeth, Have  4-chambered stomachs,  And have long intestines, because the digestion of grass is difficult.  Examples are sheep, gazelle, cows and etc. BAGHDAD COLLEGE Dr. JASIM MOHAMMED ALOBAIDI BIOLOGY CLASS 4th 4- Omnivores (plant and meat eaters): They eat both plant and meat. Have the properties of both herbivores and carnivores moderately. Examples, monkeys, birds and etc. Q/ All organisms need energy. A/ to live and complete their life cycle. The main source of energy is the radiant energy from the sun but it is unusable by all organisms. Q/ Herbivores have well-developed molar teeth, 4-chambered stomachs, and long intestines. A/ Because the digestion of grass is difficult. Food relationships NOTE/ Biotic (plants, animals, and decomposers) and abiotic factors (soil, light, water and nonliving matter) interact continuously in the balance of nature. Symbiotic Nutrition (living together): Some organisms live in close relationship. There are types of this relationship: 1-Commensalism 2-Mutualism (Mutual Benefit) 3-Parasitism 4-Saprophytic nutrition (decomposers) 1-Commensalism:  Commensalism: one organism benefits and the other is neither harmed nor helped. The helping organism is called commensal.  For instance, small fish (Echeneis) attach to sharks and live with them.  These small fish feed on the residue of the shark’s prey.  Here, while the small fish benefit, the shark (commensal) is not affected.  Clown fishes often form symbiotic association with sea anemones,  Gaining protection by remaining among their tentacles and gleaning scraps from their food. 2-Mutualism (Mutual Benefit):  In this type of relationship both organisms benefit.  Lichens and the rhizobium bacteria (Rhizobium leguminosarum) with legume plants are a typical example.  Lichens: are composed of fungi and green algae. BAGHDAD COLLEGE Dr. JASIM MOHAMMED ALOBAIDI BIOLOGY CLASS 4th  Fungi protect the algae and provide them with water and CO2.  Green algae supply the fungi with food and O2.  The rhizobium bacteria (Rhizobium leguminosarum) and legume plants.  These bacteria live in the root nodules of legume plants.  Saprophytic rhizobium bacteria live in the soil and when they encounter the roots of legume plants, they enter the root hairs and pass to the cortex cells, where they reproduce using the food and enzymes of the plant.  Host cells activated by the bacteria multiply quickly and form pocket-like bacteria containing nodules.  Here the plant gets the advantage of atmospheric nitrogen, which is fixed by the bacteria.  The plant provides the bacteria with shelter and the products of photosynthesis. Q/ Explain mutualism with an example. A/ In this type of relationship both organisms benefit. Lichens are a typical example. Lichens are composed of fungi and green algae. Fungi protect the algae and provide them with water and CO2. Green algae supply the fungi with food and O2. Q/ Rhizobium bacteria living in root nodules of legume plants are a good example of mutualism. A/ The bacteria supply the plant with nitrogen, and the plant supplies the bacteria with the products of photosynthesis. 3-Parasitism:  Parasitism: is the symbiotic relationship in which one member (parasite) benefits and the other (host) is adversely affected.  Parasites have well-developed sense and grasping organs and reproduce quickly.  On the contrary, their enzyme and digestive systems are not well-developed.  Parasites live in or on the host. They suck liquid nutrients from the host. Q/ What the differences between external and internal parasites. a) External parasites these organisms don’t have a well-developed digestive system, but internal parasites don’t have digestive systems. b) External parasites live on the host, but internal parasites live in the host. c) External parasites can partially digest food, but internal parasites live in places where digested food is available. d) Examples of external parasites are lice, fleas and bedbugs, but examples of internal parasites are plasmodium, tapeworm, roundworms and flukes. Q/ Flea and tick, external parasites, are very dangerous to humans. A/ These organisms don’t have a well-developed digestive system and suck blood for nutrition. BAGHDAD COLLEGE Dr. JASIM MOHAMMED ALOBAIDI BIOLOGY CLASS 4th Parasitic plants: Some plant species live on other plants and obtain organic or inorganic substances from them. Such plants are of two types: half-parasitic and full-parasitic. Q/ Compare between full-parasitic and half-parasitic plants. Full-parasitic plants Half-parasitic plants These plants have leaves are small, with little or no They have chlorophyll. chlorophyll, weakened xylems and, in some cases, roots disappear. The absence of photosynthesis is compensated for They carry out photosynthesis. by the development of sucking organs called Haustorium. These plants anchor their haustoria to the vascular These plants anchor their haustoria into the xylem tissue of the host plant and absorb water necessary of the host plant, absorbing water and minerals for transpiration and the food produced by the host. which they use to produce organic substances. Examples include Broom-rapes and Cuscutaceae. Mistletoe, a half parasite, lives on trees such as apple and pear. Haustorium: The developments of sucking organs of parasitic plants, these organs anchor to the vascular tissue of the host plant and absorb water necessary and the food produced by the host. Q/ Broom-rapes, a full parasitic plant, does not carry out photosynthesis. A/ but these plants obtains nutrients through haustoria from the host plant. Pathogens: Many bacteria and fungi live parasitically on higher plants and animals and cause disease. Obligatory parasites: Parasites that can’t survive unless they are on a host organism for instance:  The bacterium that causes diphtheria is an organism unable to survive outside the human body.  Viruses are also obligatory parasites.  The bacteria that cause cholera and tetanus can live in soil or water in a dormant condition. When they find suitable conditions they become parasitic and pathogenic. Q/ The bacteria that cause cholera and tetanus can live in soil or water in a dormant condition. A/ When they find suitable conditions they become parasitic and pathogenic. READ ME! Parasitic plants Mutualistic symbiosis: (all the organisms involved benefit from the association such as the interaction between higher plants and mycorrhizas or nitrogen-fixing bacteria). BAGHDAD COLLEGE Dr. JASIM MOHAMMED ALOBAIDI BIOLOGY CLASS 4th Parasitic symbiosis: (only one of the organisms involved benefits to the detriment of the other organism of the interaction such as the interactions between higher plants are usually parasitic, involving a non- parasitic host and a hemi- or holoparasitic plant). Q/ About 1% of all flowering plants, roughly 3000 species, is parasitic. A/ They form a close connection with the vascular system of the host through a so-called haustorium and are at least partially dependent on the host for their supply of water, nutrients and organic solutes. For instance: Parasitic angiosperms may be classified as: 1. Either root parasites (60%) or stem parasites (40%), depending on whether the haustorium is below or above soil surface. 2. The presence (hemi-parasites) or absence (holo-parasites) of chlorophyll. Approximately 20% of all parasites are holo-parasitic, the remainder being hemi-parasitic:-  All chlorophyll-lacking species are obligate parasites, meaning they cannot establish and develop independently.  Other parasitic plants are facultative parasites; they can establish and grow independently but in field situations always meet a wide variety of hosts and behave heterotrophic. 4- Saprophytic nutrition (decomposers):- Saprophytic nutrition (decomposers): - is a type of heterotrophy. Some bacteria and fungi feed on and digest organic substances in decaying animal and plant remains, and have a well-developed digestive system. Q/ Some bacteria and fungi are called decomposers. A/ They practice extracellular digestion and convert organic substances in decaying animal and plant remains into inorganic ones. In this way they clean the environment and contribute to the nitrogen cycle. Q/ Some bacteria and fungi are clean the environment and contribute to the nitrogen cycle. A/ Bacteria (Proteus vulgar)and fungi that get food from the nitrogenous organic compounds of dead plants and animals cause decomposition and putrefaction, and enable matter to cycle in nature. Food chain Food chain: The series of steps through which energy is transferred from the sun to organisms (producers, consumers, decomposers) in an ecosystem. Q/ The main source of energy are the radiant energy from the sun but it is unusable by all organisms. BAGHDAD COLLEGE Dr. JASIM MOHAMMED ALOBAIDI BIOLOGY CLASS 4th A/ So that, it has to be converted into a usable form by photosynthetic reactions, and then transferred from one organism to another in the form of organic compounds. A food chain consists of producers, consumers and decomposers. 1- Producers: The bacteria, protists and plants that can convert light energy into chemical energy. Q/ Producers are organisms form the first link of the food chain. A/ For this reason, on land, the food chain generally starts with flowering plants, in aquatic places it starts with microscopic algae. 2- Consumers: a- Primary consumers  These are the animals that feed on plants, the herbivores.  Examples are insects, gnawing mammals and ruminants.  Mollusks and crustaceans that feed on phytoplankton in marine and freshwater are also herbivores. b- Secondary and tertiary consumers  Secondary consumers are organisms that feed on herbivores.  Tertiary consumers are organisms that feed on secondary consumers.  Animals of both groups catch their prey and have features for killing and tearing it before eating. 3-Decomposers: are mainly bacteria and fungi. Q/ Decomposers are organisms have a very important role in ecosystems. (Or) What are the importance's of decomposers? A/ If decomposers didn’t decay this layer of leaves every year it would accumulate, cover the trees and kill them. These organisms decompose dead animals. Nutrition starts with plants and passes to different animals. Most of the animals in a food chain feed on more than one type of food. Food webs: Each ecosystem has a trophic structure (Each level in food web is called a trophic level) of feeding relationships. The first trophic level is formed by producers, the second trophic level by primary consumers (herbivores), and the third trophic level by secondary consumers (carnivores). Q/ Food relations in a community or an ecosystem are not formed from a regular chain. A/ Sometimes they contain complex interconnections of many food chains called a food web. Food webs may have short and long chains. Q/ Carnivores have a complex structure and form a web. A/ Carnivores have a variety of food sources which causes the chain. For example, falcons and eagles eat different bird species, snakes and small mammals. BAGHDAD COLLEGE Dr. JASIM MOHAMMED ALOBAIDI BIOLOGY CLASS 4th Q/ The consumers located at the higher levels of food chains are not always carnivores. A/ But sometimes parasites or organisms feeding on organic wastes. Q/ What the most important feature of parasitic food chains. A/ The organisms are at the higher levels are smaller than the organisms at the lower levels. In other words, it goes from bigger organisms to smaller organisms, like dog to flea. The food web is found in an aquatic ecosystem. Q/ A food web aren't as regular as a food chain in an aquatic ecosystem. A/ Because the food web is starts with phytoplankton and continues with various animals, sometimes interconnected with different chains, and ends in decomposers. Ecological Pyramids Ecological Pyramids: The values of some ecological factors can be shown in a pyramid for a concretely explanation. Examples are energy pyramids; biomass pyramids and numbers pyramids. BAGHDAD COLLEGE Dr. JASIM MOHAMMED ALOBAIDI BIOLOGY CLASS 4th Q/ Ecological pyramids are prepared on the basis of biomass. A/ which includes the number of individuals of the community and ecosystem, and energy. Biomass of terrestrial animals is 1% of the biomass of terrestrial plants. More than 90% of this animal mass is invertebrates. Q/ Compare between the types of ecological pyramids. Biomass pyramids Numbers pyramids Energy pyramids Biomass means “living weight” is It shows the total number of It indicates the energy content in a quantitative estimate of the organism at each trophic level in a the biomass of each trophic level. total mass or amount of living given ecosystem. material in a particular ecosystem. Biomass decrease up to the end The number of individuals is The total amount of energy is the of the chain or pyramid from highest at the bottom of the greatest in the lowest layer. As producers to consumers. pyramid and lowest at the top. you go up, energy decreases. The kilogram is used in this Used in this pyramid numbers This pyramid uses the unit joule pyramid A biomass pyramid is not the best A numbers pyramid is not the An energy pyramid is the best way to explain the flow of best way to explain the flow of way to explain the flow of nutrients in an ecosystem. nutrients in an ecosystem. nutrients in an ecosystem. For example, Organisms may be An example. Plant (1000 tons)- Energy pyramids are shown as either plant biomass or animal Grasshopper (27,000,000) - Frog triangles because energy is lost at biomass. The total weight of the (90,000) - Trout (300) - Human every level. Energy pyramids roots, stems and spikes of wheat (1). When you look at the food illustrate how much energy is in a one hectare wheat field is chain above carefully you will see transported to the ultimate called biomass. that a human is at the end. consumers in ecosystems. NOTE / The organisms in the chain convert only 10% of the energy in food into biomass. Q/ Ecological numbers pyramids are preference the short food chains over large food chains. A/ the shorter the food chain the less energy lost, the lowest layer of the pyramid has the greatest number of individuals. Photosynthetic organisms use only 1% of light energy in photosynthesis. Other organisms and humans convert 10% of the ingested food into biomass. BAGHDAD COLLEGE Dr. JASIM MOHAMMED ALOBAIDI BIOLOGY CLASS 4th Q / at every step in the food pyramid, the accumulation of chemicals increases. A/ The organisms at the top of the pyramid are the most vulnerable to poisonous chemicals, like DDT, cyanide and other chemicals cannot be excreted from the body, and their concentration increases at every level of the pyramid. Q / There is an inverse relationship between body size (biomass) and numbers of organisms in numbers pyramid. A / the number of large organisms is small, and the number of small organisms is large in a food chain. Q/ Explain the energy pyramid. A/ It indicates the energy content in the biomass of each trophic level. An energy pyramid is the best way to explain the flow of nutrients in an ecosystem. These pyramids demonstrate how energy is lost between layers. The total amount of energy is the greatest in the lowest layer. As you go up, energy decreases. Q/ Energy pyramids are shown as triangles. (Or) Explain energy transferring from one level to another in energy pyramid. A / These pyramids are demonstrated how energy is lost between layers, because energy is lost at every level. BAGHDAD COLLEGE Dr. JASIM MOHAMMED ALOBAIDI BIOLOGY CLASS 4th Energy flow Energy flow: The main energy source that powers natural systems is the sun. While plants utilize solar energy directly through photosynthesis, animals make use of it indirectly. Q / Energy are present in various forms in nature. A / Such as mechanical, chemical, electric, nuclear, heat and light energy. Living things need all of these except nuclear energy. Q /Energy must be converted from one form to another. A / to the continuity of life. For instance, a person walks because the chemical energy of food is converted to mechanical energy. After energy is used to perform body functions, the remaining energy is heat energy. Primary products: the organic substances produced by green plants. Secondary products: the organic substances produced by herbivores that feed on the primary products. Tertiary products: the organic substances produced by carnivores that feed on secondary products. Q / Generally 90% of the energy are lost from one layer to the next, in accordance with the second law of thermodynamics. A / Only 10% of the energy is transferred to the next layer. This energy is called usable energy, and biologists refer to the “10% law”. Consequently, energy flow is the greatest at the beginning of the food chain, and smallest at the end. The remaining energy is lost as heat. BAGHDAD COLLEGE Dr. JASIM MOHAMMED ALOBAIDI BIOLOGY CLASS 4th READ ME! Energy from the sun  Our sun is an ordinary star, average in size and brightness.  Energy from the sun travels through 93 million miles of space in only eight minutes to reach us here on Earth.  The sun: is a huge bell-shaped cloud of hot gases held together by gravity.  During fusion, a tiny amount of mass is lost.  One helium atom weighs just a little bit less than two hydrogen atoms.  That little bit of mass is transformed into an enormous amount of energy, mainly infrared and visible light, which radiates in all directions through space.  The sun has been emitting energy constantly for about five billion years.  Astronomers estimate it will continue for another five billion.  Only a small fraction of solar radiation (one part in two billion) reaches the earth.  The sun is the source of almost all the energy on earth, including our food and our fuel.  Every day, Earth is bombarded by about 1022 joules (j) of solar radiation (1 j = 0.239 calories). This is the energy equivalent of 100 million atomic bombs the size of the one dropped on Hiroshima.  Much of the solar radiation that reaches the biosphere lands on bare ground and bodies of water that either absorb or reflect the incoming energy.  Only a small fraction actually strikes algae, photosynthetic bacteria, and plant leaves, and only some of this is of wavelengths suitable for photosynthesis.  Of the visible light that does reach photosynthetic organisms, only about 1% to 2% is converted to chemical energy by photosynthesis.  Primary producers on Earth collectively manufacture about 170-200 billion tons of organic material per year. Q / How does the sun make energy? A / The sun is a huge bell-shaped cloud of hot gases held together by gravity. It is made up mostly of hydrogen and helium. Inside the sun, hydrogen atoms moving very quickly collide with one another. Sometimes they combine to make helium atoms in a nuclear process called fusion. Elements cycles Elements cycles (Nutrient cycles): Is the cycling of matter from the environment to living things and back to the environment. Q / The earth are essentially a closed system (a system from which matter cannot escape). BAGHDAD COLLEGE Dr. JASIM MOHAMMED ALOBAIDI BIOLOGY CLASS 4th A / The materials are used by organisms cannot be lost and it can change its location so materials are re- used and are often re-cycled in the ecosystem. There are four elements cycles are important for living things: - Water cycle - Carbon cycle - Nitrogen cycle - Phosphorus cycle NOTE / Carbon, Nitrogen and Water have gaseous forms and they involve atmosphere so they cycle over large distances. But phosphorus is an element completely nongaseous and as a result the phosphorus cycle does not involve the atmosphere, just a local cycling. 1- Water cycle The water cycle (the hydrologic cycle): is a continuous process by which water moves from the earth's surface (lithosphere and hydrosphere) to the atmosphere and back. Or Water cycle: involves an exchange of water between the land, the atmosphere, and living things. Q / The cycling of water are occurs regularly. A / Because the influence of sun energy and gravity. Q / Explain the processes which made up the water cycle. A / a- Precipitation:  Of the Earth’s total precipitation (rainfall), 465,000 km3 falls in the sea and 100,000 km3 falls on land.  There are a strong relationship between the location, duration, and amount of precipitation, and living things. Q / Organisms cannot always use the available water directly. A / As many factors limit this use: For example, the salinity of seawater and the frozen state of polar water restrict their use by terrestrial organisms. Consequently, living organisms use only 2.6% of the total water mass. At present, rapid population increase and high technology increase the need for water. b- Evaporation:  Underground and surface water collects in lakes and seas. BAGHDAD COLLEGE Dr. JASIM MOHAMMED ALOBAIDI BIOLOGY CLASS 4th  From there, as the water warms, it evaporates and enters the air as vapor. Or Water absorbs energy and evaporates, and stays in the atmosphere as vapor. c- Condensation:  As the water vapor rises it collides with cold air currents.  The cooled vapor drops back to the earth as rain and snow.  Some water falls into the sea, and the cycle begins again. Q / The water cycle operate on two physical principles, namely evaporation and condensation. A / Water absorbs energy and evaporates, and stays in the atmosphere as vapor (Evaporation). As the water vapor rises it collides with cold air currents. The cooled vapor drops back to the earth as rain and snow (Condensation). Some water falls into the sea and the cycle begins again. The global water cycle - pathways and fluxes. (Values in 103 km3/yr.). 2- Carbon cycle Q/ What is the main source of carbon for organisms? A/ The main source of carbon for organisms is CO2. Carbon dioxide is found in the lithosphere, hydrosphere, atmosphere and biosphere.  Carbon is in the atmosphere as CO2.  In the hydrosphere as bicarbonate ion (HCO3).  In the lithosphere as coal, petroleum, limestone and natural gas.  And in the biosphere as the basic raw material of organic substances. BAGHDAD COLLEGE Dr. JASIM MOHAMMED ALOBAIDI BIOLOGY CLASS 4th Q / The carbon and oxygen cycles are closely related in nature. A / 1- The product of organismal respiration and other sources like forest fires, CO2 is used in photosynthesis and organic molecules and O2 are produced. 2- In respiration, water and CO2 are produced from the burning of organic molecules with O2. Q / The amount of CO2 in the atmosphere vary from day to night and with the seasons. A / 1- At night, when photosynthesis are stops and all organisms are respiring, the CO2 level in the atmosphere rises. 2- Likewise, in the seasons when photosynthesis is fast, the CO2 level in the atmosphere falls. Q / Much research have demonstrated that an increase of CO2 in the atmosphere results in climatic change, the greenhouse effect. A / because atmospheric CO2 are reduces the reflection of sunlight entering the atmosphere. Q/ What is the role of saprophytic bacteria and fungi in carbon cycle? A / Saprophytic bacteria and fungi also play a role in returning carbon to the atmosphere. These organisms are essential in the decomposition of dead organisms into inorganic substances. Q / Decomposition do not occur completely. A / 1- Carbon in plant and animal structures is locked into underground reserves through carbonization and petroleum formation. 2- When these formations are extracted and burned as gasoline, natural gas, and coal, CO 2 is released into the environment and used again in photosynthesis. Q / Carbon dioxide concentrations in aquatic environments are quite different from those on land. A / Carbon dioxide easily dissolves in water and forms carbonic acid (H2CO3), which ionizes to H+ and HCO3. These ions determine the pH of water. BAGHDAD COLLEGE Dr. JASIM MOHAMMED ALOBAIDI BIOLOGY CLASS 4th 3- Nitrogen cycle  The cycle of nitrogen between organisms and the atmosphere is a very long and complex process.  The major sources of nitrogen are the atmosphere and living organisms. The most abundant gas in the atmosphere (78%) is N2.  This atmospheric nitrogen can be used directly by some microorganisms.  Plants can use nitrogen in the form of nitrate (NO3) and ammonium (NH4) salts.  Animals obtain nitrogen from the proteins of the organisms they eat. Q / The nitrogen molecule (N2) are an important for organisms. A / Nitrogen is a component of molecules like amino acids, nucleic acids, hormones and vitamins. Q / List the major steps of nitrogen cycle. A/ 1-Nitrogen fixation: Nitrogen fixing bacteria including cyanobacteria converts atmospheric nitrogen gas (N2) into ammonia (NH3) and ammonium (NH4+) 2-Nitrification: Ammonia is converted into nitrate (NO3–) by bacteria in the soil known as nitrifying bacteria. Nitrate is the main form of nitrogen absorbed by plants. 3-Assimilation: Plants use nitrate when they produce protein, nucleic acid and other nitrogen containing compounds, then animals eat plants and nitrogen can pass to animals. 4-Ammonification: When plants and animals die, the nitrogen compounds in their body are broken down by ammonifying bacteria. And one of the products of this process is ammonia (NH4+). 5-Denitrification: Nitrogen is returned to the atmosphere by denitrifying bacteria, which converts nitrate (NO3–) to nitrogen gas (N2). BAGHDAD COLLEGE Dr. JASIM MOHAMMED ALOBAIDI BIOLOGY CLASS 4th Q / Oxygen are essential for the survival of living things. A / a- Oxygen is necessary for respiration and the oxidation of organic substances. b- Is used in the burning (oxidation) of coal, wood and gas. c- The atmosphere is 21% oxygen, and 5 % is dissolved in the hydrosphere. d- The oxygen in nature is produced as a result of photosynthesis. e- Oxygen also makes up the ozone layer, ozone (O3) being released as a result of the photolysis of water. 4- Phosphorus Cycle Q / Phosphorus are another element that is very important for life. A / a- Phosphorus is required for the synthesis of nucleic acids, phospholipids and ATP molecules. b- Moreover it is a component in the structure of the cell membrane, skeleton and skin. c- Certain observations made in oceans show that there is a relationship between fish size, plankton and phosphorus concentration in the water. Q / The phosphorus cycle are quite different from the nitrogen cycle. A / phosphorus does not exist in a gaseous state and therefore does not enter the atmosphere. Phosphorus cycles from land to ocean sediments and back to the land. Q / Explain the phosphorus cycle.  As water runs over rocks containing phosphorus, it gradually erodes the surface and carriers off inorganic phosphate (PO4 –3) molecules.  The erosion of phosphorus from rocks releases phosphate into the soil where it is absorbed by plant roots.  Once inside the plant cells it is converted to organic phosphates.  Animals obtain most of their required phosphorus from the food they eat and the water they drink.  The remains of dead plants and animals are decomposed to inorganic substances that can be reused by plants.  Phosphorus is significant in the efficiency of aquatic and terrestrial habitats. Consequently it is a factor that determines the efficiency of ecosystems. Q / Count the effects that increase phosphate flow to the seas. A / a- Phosphate is also mined for agricultural use as phosphate fertilizers. b- Erosion caused by human activities, household wastes, and phosphate containing detergents. BAGHDAD COLLEGE Dr. JASIM MOHAMMED ALOBAIDI BIOLOGY CLASS 4th Q / phosphate fertilizers affect the phosphate cycle rate. A / Because its speeds up the flow of phosphate from land to sea. Phosphate fertilizers don’t remain long in the soil and are carried from the land by streams and rivers to the sea.