Theory of Evolution by Natural Selection PDF

Theory of evolution by natural selection (explains the diversity of living things and is supported by a range of scientific evidence) a. describe scientific evidence that present-day organisms have evolved from organisms in the past - Fossils: fossils offer a chronological record of the ear...

Theory of evolution by natural selection (explains the diversity of living things and is supported by a range of scientific evidence) a. describe scientific evidence that present-day organisms have evolved from organisms in the past - Fossils: fossils offer a chronological record of the earth and the creatures that lived during those times. By examining the fossil records, scientists can discover how a species has evolved over time by seeing the changes within the fossils. An example of the fossil record is archaeopteryx, a flying dinosaur that shows the transition from dinosaurs to birds. Some of the preserved specimens show evidence of feathers and wings, characteristics found in modern birds. - Observational: Some forms of evolution can be seen throughout our own lifetime, an example of this is bacteria becoming resistant to antibiotics. Other observational evolutionary changes include animals such as the stickleback, they have been seen to have different DNA codes for their pelvic fins depending on where they live, showing the evolution from salt water stickleback to freshwater stickleback. They also have fossil records of stickleback deleting and rewriting this specific genetic code over and over again within millions of years, displaying the evolution of the fish and how the same evolution can occur time and time again if they are given the same circumstances. b. relate the fossil record to the age of the Earth and the time over which life has been evolving - Fossils provide records for Palaeontologists to either estimate or give an exact date of when an organism died → ie, what time period, what lead to its death, and how its fossil differs from that of older and newer organisms - Dating fossils is not a romantic pursue of dead creatures, but means determining the age of a fossil → allows palaeontologists to construct a timeline showing when each organism lived on Earth (there are two kinds of dating) - Absolute dating uses physical properties such as radioactivity to determine the actual (exact) age of rocks and fossils - Relative dating compares the age of one fossil or rock with another to determine which is older ; this relies on the facts that sedimentary rocks form layers and fossils are the same age as the rocks in which they are found 1. Principle of original horizontality: layers of strata are deposited horizontally or nearly horizontally 2. Principle of superposition: Younger sedimentary rocks are deposited on top of older sedimentary rocks. 3. Principle of cross-cutting relations: Any geological feature is younger than anything else that it cuts across. c. explain, using examples, how natural selection relates to changes in a population, e.g. in the development of resistance of bacteria to antibiotics and insects to pesticides - Natural selection is a process where individuals with traits that provide survival advantages in a population are passed to offspring, leading to changes in the population over generations. - The theory of evolution by natural selection was proposed by Charles Darwin, describing how species evolve and change over time, with beneficial traits becoming more common - E.g. Antibiotic resistance in bacteria - When bacteria are exposed to antibiotics, some will have mutations that provide resistance to the antibiotic. Those that survive reproduce, passing on the resistance gene to their offspring and over time, the whole population of bacteria becomes resistant to that antibiotic → scientists will have to create an even more potent and powerful antibiotic d. outline the roles of genes and environmental factors in the survival of organisms in a population - Genes: heredity (inherited & passed on), determines specific traits in organisms like fur colour, body structure, resistance to diseases. Genetic variation within a population means that some individuals have traits better suited to their environment, increasing chances of survival & reproduction. - E.g. The ability to camouflage is a product of genes and the theory of evolution for an animal to survive. - Environmental Factors: climate, food availability, predators exert pressure on populations. Environmental factors determine which traits are advantageous, driving the process of natural selection. - E.g. In colder environments, animals with thicker fur are more likely to survive and reproduce. The theory of plate tectonics a. outline how the theory of plate tectonics changed ideas about the structure of the Earth and continental movement over geological time - Before the discovery of plate tectonics, many people believed that Earths continents were fixed in place. Then ALFRED WEGENER suggested that continents could drift, and they had drifted apart in the early 20th century. - However, only in the 1660s was an explanation of how continents moved, proposing that the outer layer ( the lithosphere) is divided into large chunks that float on the mantle (asthenosphere). - The discovery of mid-ocean ridges, patterns of earthquakes, and seafloor spreading provided critical evidence, changing the perception of Earth as a static planet to one with a dynamic, ever-evolving crust. b. relate movements of the Earth's plates to mantle convection currents and gravitational forces - Mantle Convection Currents: Heat from Earth’s core creates convection currents in the mantle, where hotter, less dense material rises toward the lithosphere, then cools and sinks back down. This cycle exerts a dragging force on the plates, causing them to move. - Gravitational Forces: Gravity also plays a role, especially in “slab pull” and “ridge push” mechanisms. In slab pull, the weight of a subducting (sinking) plate pulls it deeper into the mantle, while ridge push occurs at mid-ocean ridges, where newly formed, hot lithosphere pushes plates apart as it cools and becomes denser. - c. outline how the theory of plate tectonics explains earthquakes, volcanic activity and formation of new landforms - Earthquakes: Earthquakes are caused by the movement of tectonic plates at faults, or fractures in the Earth's crust, when diverging, converging, sliding or subduction occurs. - Convergent boundaries: These occur where plates move toward each other. They can lead to subduction zones (where an oceanic plate sinks beneath a continental plate), mountain-building, volcanic activity, and earthquakes. - Divergent boundaries: These boundaries, plates move apart from each other, commonly seen at mid-ocean ridges. This movement allows magma to rise, creating new crust as it cools, contributing to seafloor spreading. Divergent boundaries are also associated with volcanic activity and earthquakes. - Transform boundaries (slip fault): Plates slide horizontally along each other, releasing seismic waves and hence an earthquake (e.g. San Andreas Fault) - Volcanoes: A rupture in the crust, found at a destructive or constructive plate boundary - Destructive (convergent): When oceanic and continental plates CONVERGE where the oceanic plate subducts under the continental plate (as it is denser), creating gas and heat, causing a rupture in the Earth’s crust, and forming volcanoes along the boundary (E.g. Ring of Fire) - Constructive (divergent): When oceanic plates DIVERGE and create a gap in the Earth’s crust, where magma from the mantle fills the space, forming a new crust (seafloor spreading). During this process it is common for pressure to build up and force large amounts of magma out of magma chambers, causing volcanic eruptions. - Hotspot Volcanoes: Occurs over exceptionally hot areas of the mantle, where rising magma that melts the tectonic plate above, and builds up causing round volcanic landforms, (e.g. Hawaiian Islands) - There are 2 types of volcanoes: 1. Strato/Composite Volcanoes:  - Found at a DESTRUCTIVE boundary - Erupts violently - Conical shape - Erupts: lava, lava bombs, gas, tephra (rock fragments/particles) 2. Shield Volcanoes - Erupts less violently, flowing down sides of volcano - Smoothly edged sides - Formed on a CONSTRUCTIVE boundary or hotspots - Fluid, gooey lava - Erupts: lava, lava bombs, gas, tephra (rock fragments/particles) - New Landforms: - Mountains: Formed at CONVERGENT boundaries, and can be created in 3 different ways, depending on the types of plates that are colliding - Oceanic to Oceanic: The denser of the two plates subducts under the other, leading to the formation of volcanic island arcs, and underwater mountain ridges - Oceanic to Continental: The denser plate (oceanic) subducts under the continental, causing an uplift of mountain ranges along the continental edge - Continental to Continental: As their densities are the same, instead of subducting, they crumple and fold, leading to significant uplift and the formation of mountains. - Composite Volcanoes (Stratovolcanoes): Formed by layers of lava flows, ash, and volcanic rocks from repeated eruptions. These tend to be tall, steep, and cone-shaped, like Mount St. Helens. - Shield Volcanoes: Built from fluid lava flows that spread out over large areas, creating wide, gently sloping mountains like Mauna Loa in Hawaii. - Cinder Cones: Small, steeply sloped volcanoes formed from the accumulation of volcanic debris like ash and rocks around the eruption site. - d. describe how some technological developments have increased scientific understanding of global patterns in geological activity, including in the Asia-Pacific region 1. Seismology and Earthquake Monitoring Systems Seismographs and seismometers measure ground movements caused by earthquakes and volcanic eruptions. Modern seismic networks track earthquakes with high precision, allowing scientists to understand the structure of Earth’s crust and monitor tectonic activity. The Asia-Pacific region, particularly the "Ring of Fire," experiences frequent seismic activity. With advanced seismology tools, scientists can analyze seismic waves to  locate earthquake epicenters, map fault lines, and study how energy is distributed during an earthquake, enhancing preparedness and resilience strategies. 2. Global Positioning System (GPS) GPS technology measures the movement of tectonic plates with millimeter precision. By placing GPS receivers on tectonic plates, scientists can monitor their speed and direction, giving insight into patterns of geological stress. In the Asia-Pacific, GPS data has revealed the collision between the Indo-Australian and Eurasian plates, which is responsible for earthquake-prone zones across Indonesia, the Philippines, and Papua New Guinea. 3. Remote Sensing and Satellite Imagery Satellite-based remote sensing uses radar and infrared imagery to monitor volcanic eruptions, ash clouds, and changes in land elevation. Satellites like Sentinel and Landsat enable scientists to observe active volcanoes, track ash plumes, and measure the deformation of volcanic domes. In the Asia-Pacific, satellite imagery has been critical for monitoring eruptions like those of Mount Agung in Indonesia and Mount Pinatubo in the Philippines. This real-time data is essential for early warning systems and public safety.