Biology Test Chapter 10,11,12
Terms
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- Bottleneck Effect:
- an event in which a population’s size is greatly reduced. When this happens, genetic drift may have a substantial effect on the population. In other words, when the population size is radically reduced, gene frequencies in the population are likely to change just by random chance and many genes may be lost from the population, reducing the population’s genetic variation.
- Genetic Drift:
- random changes in the gene frequencies of a population from generation to generation. This happens as a result of sampling error—some genotypes just happen to reproduce more than other genotypes, not because they are “better,†but just because they got lucky. This process causes gene frequencies in a population to drift around over time. Some genes may even “drift out†of a population (i.e., just by chance, some gene may reach a frequency of zero). In general, genetic drift has the effect of decreasing genetic variation within a population.
- Founder Effect
- changes in gene frequencies that usually accompany starting a new population from a small number of individuals. The newly founded population is likely to have quite different gene frequencies than the source population because of sampling error (i.e., genetic drift). The newly founded population is also likely to have a less genetic variation than the source population.
- Speciation:
- Changes in related organisms to the point where they are different enough to be considered separate species. This occurs when populations of one species are separated and adapt to their new environment or conditions (physiological, geographic, or behavioral).
- Allopatric speciation:
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Speciation that occurs when two or more populations of a species are geographically isolated from one another sufficiently that they do not interbreed.
gene flow: The movement of genes into or through a population by interbreeding or by migration and interbreeding. - Non-random mating:
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individuals are more likely to mate with close relatives (e.g. their neighbors) than with distant relatives. This is common in the Amish community.
• Ellis Van Crevald Syndrome – Have symptoms of; Shortened Limbs, Malformed Heart and six fingers per hand - Punctuated Equilibrium:
- hypothesis that suggests that much of evolutionary history is characterized by stasis punctuated by relatively rapid character change as a lineage splits. Available fossil evidence has highlighted several lineages that seem to follow this pattern of evolution.
- Gradualism Equilibrium:
- The Darwinian view of natural selection leading to slow, continuous evolution over long spans of time with occasional speciation is called gradualism.
- Convergent Evolution:
- : causes structures in different species to have similar form due to similar environmental pressures.
- Divergent Evolution
- causes structures in related species to have different form/function due to different environmental pressures
- Homologous Structures:
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The structures shared by a set of related species because they have been inherited, with or without modification, from their common ancestor. For example, the bones that support a bat's wing are similar to those of a human arm.
⬢ Human Arms and Seal Flipper are homologous structures derived from a common ancestral structure. - analogous structures
- Structures in different species that look alike or perform similar functions (e.g., the wings of butterflies and the wings of birds) that have evolved convergently but do not develop from similar groups of being born from the division of the zygote ((the earliest stage, in which joined egg and sperm have not yet divided), and that have not evolved from similar structures known to be shared by common ancestors. Contrast with homologous structures.
- Natural Selection:
- A process in which some individuals have genetically-based traits that improve survival or reproduction and and thus have more offspring surviving to reproductive age than other individuals. Because the offspring also carry the genes for these traits, this process causes the genes for advantageous traits to become more common in populations and the genes for disadvantageous traits to become less common in populations.
- stabilizing selection:
- A form of selection that tends to keep the form of a population constant. Individuals with the mean value for a character have high fitness (The success of an individual (or allele or genotype in a population in surviving and reproducing, measured by that individual's genetic contribution to the next generation and subsequent generations.; those with extreme values have low fitness).
- Directional Selection:
- favors one extreme phenotype
- disruptive selection:
- Selection favoring forms that deviate in either direction from the population average. Selection favors forms that are larger or smaller than average, but works against the average forms between the extremes.
- Balanced Polymorphism
- - A situation in which it is beneficial for a population to maintain two different alleles creating different phenotypes within the population. It’s also a change of shape. Examples such as Sickle Cell Anemia.
- Preadaptation:
- A characteristic evolved by an ancestral species or population that serves an adaptive though different function in a descendant species or population.
- adaptation:
- Any heritable characteristic of an organism that improves its ability to survive and reproduce in its environment. Also used to describe the process of genetic change within a population, as influenced by natural selection.
- Microevolution:
- evolution within a species or population. An increase in a particular gene’s frequency in a population due to natural selection is an example of microevolution.
- Macroevolution:
- can be defined simply as evolution above the species level, and its subject matter includes the origins and fates of major novelties such as tetrapod limbs and insect wings, the waxing and waning of multi-species lineages over long time-scales, and the impact of continental drift and other physical processes on the evolutionary process.
- adaptive radiation:
- The diversification, over evolutionary time, of a species or group of species into several different species or subspecies that are typically adapted to different ecological niches (The ecological role of a species; the set of resources it consumes and habitats it occupies.) (for example, Darwin's finches). The term can also be applied to larger groups of organisms, as in "the adaptive radiation of mammals."
- Quantitative Variation:
- Measured in degrees
- Discrete Variation:
- Control by 1 gene.
- Index fossils:
- (or zone fossils) are fossils used to define and identify geologic periods (or faunal stages). They work on the premise that, although different sediments may look different depending on the conditions under which they were laid down, they may include the remains of the same species of fossil. If the species concerned were short-lived (in geological terms, lasting a few hundred thousand years), then it is certain that the sediments in question were deposited within that narrow time period.
- Radioactive Dating:
- A method of determining the date at which an igneous rock solidified based upon the rate of decay of radioactive atoms within the rock.
- half-life:
- The amount of time it takes for one-half of the atoms of a radioactive material to decay to a stable form. For example, the half-life of carbon-14 is 5,730 years.A 19th-century scientist considered a father of modern geology. Lyell proposed that the geology of Earth is shaped by gradual processes, such as erosion and sedimentation. Lyell's ideas, expressed in his landmark work, Principles of Geology, greatly influenced the young Charles Darwin. Darwin and Lyell later became close friends. While Lyell initially opposed the idea of evolution, he came to accept it after Darwin published On the Origin of Species.
- Cuvier -
- At the beginning of the nineteenth century, the great French geologist and naturalist Baron Georges Cuvier proposed what came to be known as the Catastrophe theory or Catastrophism. Catastrophism is the theory that Earth has been affected by sudden, short-lived, violent events that were sometimes worldwide in scope.
- Lyell:
- Charles Lyell was the popularizer of uniformitarianism which is the idea that the earth is always changing in a slow pace.
- Lamarck, Jean:
- An 18th-century naturalist, zoologist, and botanist noted for his study and classification of invertebrates, as well as his evolutionary theories. He traveled extensively throughout Europe and was elected to the Academy of Sciences, where he introduced the principles of heredity and acquired characteristics which is the hereditary mechanism by which changes in physiology acquired over the life of an organism (such as muscle enlarged through use) are transmitted to offspring.
- Charles Darwin:
- He believed in evolution through natural selection
- acquired trait:
- A phenotypic characteristic, acquired during growth and development, that is not genetically based and therefore cannot be passed on to the next generation (for example, the large muscles of a weightlifter).
- vestigial:
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Any structures that have been greatly reduced in size and function over evolutionary time to the extent that they now appear to have little or no current function.
• Examples of vestigial structures in humans include wisdom teeth, the coccyx and the vermiform appendix.
• A whale’s pelvis is evidence of its evolution from four legged land-dwelling mammals.
• Eyes on a fish are not needed because they can’t see. - Similarities of Developmental patterns:
- The human embryo and the chicken embryo have similar embryo’s each having a bony tail and simliar gill pouches which are simliar to those of a fish.
- Evidence for Evolution:
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In the 150 years since Darwin proposed the theory of evolution by natural selection, a mountain of evidence has accumulated to support the theory. A greatly expanded fossil record since Darwin's time, the discovery of DNA and the process of genetic replication, an understanding of radioactive decay, observations of natural selection in the wild and in laboratories, and evidence in the genomes of many different organisms, including humans, have all bolstered the validity of the theory of evolution.
⬢ Peppered Moth
⬢ Homologous Structures
⬢ Fossil Record
⬢ Vestigal Structures
⬢ Preadaptation
⬢ DNA
⬢ Radioactive Dating - Parts of the Theory of Evolution which are difficult to prove:
- The start of evolution
- What is the difference between gradualism and punctated equilbria
- 1. Gradualism is the hypothesis that evolution occurs at a constant rate. Punctuated equilibria is the hypothesis that evolution occurs at an irregular rate.
- What did Stanley Miller and harold Urey demostrate
- 2. They used an apparatus to simulate the conditions on the early Earth. The flask contains water and represents the ocean. Heating causes water to evaporate and move up a glass tube to the vessel representing the atmosphere. It contains a mixture of hydrogen gas, methane, ammonia, and water vapor. Sparks discharged into the mixture mimic the effects of lighting, stimulating reactions among the gases. Cold water circulates over the tubing, causing water vapor to condense, simulating rain. Thus, the products of any reaction in the “atmosphere†are carried back into the “ocean†where they can continue to react. Miller could remove samples for analysis through the valve.
- Arrange the following vertebrates in order of evolution, starting form the oldest to the most recent: bony fishes, amphibians, birds, mammals, dinosaurs, reptiles, jawless fishes, fish with jaws
- 3. Jawless fishes, jawed fishes, bony fishes, amphibians, reptiles, dinosaurs, mammals, birds
- Give two examples of how natural selection has changed two species.
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At first giraffes were born with alleles for varying neck lengths. Some had short necks and some long. Giraffes with longer necks could reach for leaves in tall trees. They were getting better at getting food, but the short necks didn’t get enough food and the longer necks got more offspring. Since there were more longer neck offspring it became more common and short necks became rare.
With the increase of factories in England pale tree trunks were blackened by
heavy pollution from factories. Maybe moths sitting on soot darkened bark escaped being eaten by birds because it was hard for the birds to see the now dark moths against the dark background. Light colored moths however were easy to see and were eaten. When they reproduced dark moths produced dark moths. Vice versa. - What are vestigial structures and what do they show.
- 5. They show the remnants of an organism’s evolutionary past.
- Explain Darwin's discoveries with the Galapagos finches.
- 6. In my book notes
- What is radioactive dating.Describe it's proccess
- 7. In notes
- What are vestigial structures and homologous structures? Name an example of each.
- 8. Already said in study guide
- Describe directional selection, stabilizing selection and disruptive selection
- 9. Already in notes
- Evolution of ? began the production of oxygen.
- 10. Cyanobacteria – photosynthetic eubacteria thought to be the first organisms to release oxygen.
- Be able to describe the concept of natural selection
- 11. In notes
- Name one method of dating fossils
- 12. Already in notes
- What are fossils
- 13. Tracks of dinosaurs, footprints of human ancestors, insects trapped in sticky tree sap, impressions of leaves or skin and animals buried in tar are all fossils. For fossils to form very special conditions are needed. The dead animal must be buried in sediment. (Solid fragments of inorganic or organic material that come from the weathering of rock and are carried and buried by wind, water, or ice) Burial is in ocean floor, in swamps, in mud, or in tar pits. Calcium in the bone or in the shell is slowly replaced by other, harder minerals. Usually skin or muscle is not fossilized.
- Why is the ozone layer improtant to the survival of life on land?
- 14. Ozone which is a gas that has the remarkable and very fortunate property of absorbing ultraviolet radiation. In the upper atmosphere, ozone acted like a great shield blocking out ultraviolet radiation. This made the Earth’s surface a safe place to live.
- Why are transitional species crucial evidence of evolution
- 15. Because then they show how new species evolved from existing species, which was one of Darwin’s main arguments.
- Describe the steps the scientists used to determine whether organic molecules that make up living things could form under conditions found on early Earth.
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16. Methods- Mix molecules found in early atmosphere. Stimulate reactions with heat and electricity. Collect and analyze products of reactions.
Key Assumptions – Experiment matches conditions on early Earth, in temperature and chemical composition. Experiment has not been contaminated by bacteria which could also produce organic molecules.
Results - Complex mixture of organic molecules forms; contains amino acids.
Conclusions – Organic molecules could have formed on early Earth before life existed. Experiments steps in question 2. - If you start with a population of 10 fast zebras and 90 slow zebras how will fast zebras become more abundant.
- 17. Over a period of time the slow zebras will die off. Look at question 4.
- How do environmental conditions lead to ecologicial races, divergence, and eventually a new species
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18. Ecological races - are populations of the same species that differ genetically because they have adapted to different living conditions.
Divergence - The accumulation of differences between species or populations. Eventually races can accumulate so many diffrences that biologists consider them separate species. Examples are the Dusky seaside sparrow, Gulf seaside sparrow, Cape Sable seaside sparrow and seaside sparrow. - Sickle Cell Anemia
- Look in textbook pg 183
- Heterotroph Theory
- In Favorites on the internet
- Other evidence for evolution besides fossils
- In notes.