Biology Study Notes - Unit 3 PDF

Biology Study Notes -- Unit 3 **Darwin's Voyage** Was to gather observations and evidence during his time aboard the HMS Beagle from 1831 to 1836. This experience helped him discover the theory of evolution through natural selection. **Darwin's Work** In 1859 Charles Darwin published a book call...

Biology Study Notes -- Unit 3 **Darwin's Voyage** Was to gather observations and evidence during his time aboard the HMS Beagle from 1831 to 1836. This experience helped him discover the theory of evolution through natural selection. **Darwin's Work** In 1859 Charles Darwin published a book called "On the Origin of Species" which was about overcoming the scientific rejection of earlier concepts of evolution. He publishes it because Alfred Russel Wallace had sent him a similar conclusion and because of his finding during his voyage. **Studies** Darwin: Charles Darwin was known for his studies of scientific theory of evolution by natural selection. Hutton: James Hutton was known for establishing the foundation of modern geology. He formulated the principle of uniformitarianism which explained the features of the earth\'s crust. Lyell: Charles Lyell was a Scottish geologist known for his master studies for the understanding of rocks and fossils. Lamarck: Chevalier de Lamarck was known for his studies of botanical (plants) and zoological (animals). He advanced the first modern theory of evolution, creating the concept of inheritance. Malthus: Thomas Malthus was known for his theory that population growth will always tend to outrun the food supply. He believed that the betterment of humankind was impossible without limits of human reproduction. He was an Economist and Demographer (statistics) **Natural Selection:** Natural selection is the variations in the genotype that increases an organism's chances of survival and procreation which was found by Charles Darwin. **Artificial Selection:** Is the identification by humans of desirable traits in plants and animals. Farmers us this to improve resistance to disease, increase crop yeilds, enhance the nutrional content and create plants with desirable physical traits. **Darwin's Concept of fitness** Charles Darwin believed that fitness was a fundemental concept in evelutionary biology **What is Survival to the fittest?** Survival to the fittest was a term made famous in the fifth edition of the book that charles darwin publishes, *On the Origin of Species.* It was suggested that organisms that adjusted to their environment are the most succsesful in surviving and reproducing. **Common Decsent:** Common decsent is the principle that all living organisms share a common ancestor from which they eveolved overtime. **Vesgitial structures:** Is a body part that no longer has a usful function in an organsim but was useful to its ancestors. For example the human appendic or tailbone. **What are fossils (in Darwins Time):** They were what supported his evolution theory. It was a record of life. **Gene Pool:** Is the collection of different genes within an interbreeding population. It includes both genes that are expressed and not expressed. **Mutation**: a change in sequence of DNA. They occur because of mistakes in DNA replication or because of radiation or chemicals in their environment. **2 main Sources of Genetic Variation:** The two main sources of genetic variation are mutation and genetic gene shuffling that result from sexual reproduction. **Single Gene Trait:** Is a trait that is controlled by only one gene. Can either be dominant or recessive. Examples are widows peak, ability to roll the tongue or earlobe attachment. **What controls the number of Phenotypes produced for a given trait?** - The number of genes involved. IS it a single gene which produces fewer phenotypes. Or Multiple genes which produce a wide range of phenotypes - How alleles interact, which dominant and recessive alleles create fewer phenotypes. - Environment, which is the conditions of sunlight or nutrition can affect how traits are expressed adding more variation. **Bell Curve:** A bell-shaped curve represents a normal distribution. It allows you to observe a particular range of values. **Directional Selection:** When individuals at one end of the curve have higher fitness than individuals in the middle or at the other end. **Stabilizing Selection:** When individuals near the Centre of the curve have higher fitness than individuals at either end of the curve. **Disruptive Selection:** When individuals at the upper and lower ends of the curve have higher fitness than individuals near the middle. **Genetic Drift:** A random change in allele frequency. May occur when a small group of individuals colonizes a new habitat. **Genetic Equilibrium:** Principle that states that allele frequencies in a population will remain constant unless one or more factors cause those frequences to change. There are 5 conditions that need to take place for genetic equilibrium to occur. - There must be random mating. - The population must be very large. - There can be no movement into or out of the population. - There can be no mutation. - There can be no natural selection. - **Reproductive Isolation:** a collection of mechanisms, behavior, and physiological processes that prevent the members of two different species mate and produce offspring. **Temporal Isolation:** Occurs when two or more species reproduce at different times. **Behavioral Isolation:** Occurs when two populations are capable of interbreeding but have differences in courtship rituals or other reproduction strategies that involve behavior. **Geographical Isolation:** Occurs when two populations are separated by geographical barriers such as rivers or mountains. **What does random mating cause to allele frequencies:** **Hardy Weinberg Principle:** States that genetic variation in a population will remain constant from one generation to the next in the absence of disturbing factors. **Endosymbiotic theory:** Proposes that eukaryotic cells arose from living communities formed by prokaryotic organisms. **What forms sedimentary Rock:** Are formed by the accumulation and lithification of sediment. **What is Speciation and what are the steps?** Speciation is the process by which new species form. It occurs when groups in a species become reproductively isolated and diverge. The four stages are allopatric, peripatric, parapatric, and sympatric. **Fossils are what, most are formed in what and some examples of what they can be:** Fossils are the preserved remains of plants and animals whose bodies were buried in sediments, such as sand and mud, under ancient seas, lakes, and rivers. **What is half Life?** The time required for a biological system, such as that of a human, to eliminate, by natural processes, half of the amount of a substance (such as a radioactive material) that has entered it. **What is an Index Fossil?** An index fossil is the remains of plants and animals that have existed only for a limited geologic period. **What is most Earths most recent Era?** Cenozoic. **Water remained in what chemical state because the earth was too hot in the early year?** In Earth\'s early years, water remained in a gaseous state (water vapor) because the planet was too hot for liquid water to form. **Dense elements are found where in earth?** Dense elements like Iron and Nickel are found in Earth's Core. **What were Millers and Urey's Experiment and what gases were used in it?** They aimed to simulate the conditions of early Earth\'s atmosphere and oceans to explore the origins of life. The two scientists combined warm water with a mixture of four gases---water vapor, methane, ammonia, and molecular hydrogen. **Proteinoid Microspheres:** Are spherical structures to be formed when a heated mixture of amino acid molecules in the dry conditions is dissolved in water. **What was it combined to form rust in the early seas?** It was made by dissolved oxygen with iron. **What were the first organisms on earth?** Microscopic organisms (microbes) **What happened at the end of the Paleozoic Era?** The era ended with the largest extinction event of the Phanerozoic Eon, the Permian--Triassic extinction event. **What were the dominant land animals for Jurassic and Cretaceous periods?** Jurassic Period: Sauropods. Theropods, stegosaurs, ornithopods. Cretaceous Period: Theropods, Ceratopsians, hadrosaurs, ankylosaurus, sauropods. **Adaptive Radiation:** When a single species rapidly evolves into many different species to fill various ecological gaps. This often happens when a species encounters new environments. **Convergent Evolution:** When unrelated species evolve similar traits or features because they live in similar environments or face similar challenges though they don't share a common ancestor. An example is that bats and birds both use wings to fly but they evolve independently. **Coevolution:** When two or more species influence each other's evolution over time. For example, a flower and its pollinating insect may evolve together. **Mass extinction encourages rapid what? And provides what to the surviving Species?** Mass extinction encourages rapid diversification and adaptive radiation. This allows the surviving species to grow and adapt can lead to the emergence of new species, traits, and ecosystems.