Exam 4 Flashcards
Evolution and Natural Selection
Describe Lamarck’s theory of evolution through inheritance of acquired characteristics. Why was it incorrect.
Characteristics change because of the use or disuse of characteristics. It was incorrect because it is not based off of what actually occurs; heredity.
Describe the importance of Darwin’s voyage abroad the HMS beagle to the development of his theory of evolution by natural selection
It allowed him to study plants in other countries.
Describe the influences of Lyells principles of Geology and malthus’s essay on the principle of population on the development of darwins theory. Define malthusian catastrophe.
Lyell’s Principles of Geology: He stated that the earth was older than we thought. Opened up the possibilities of biodiversity over time.
Malthus’s Essay: People having more children than people dying, but the population stayed constant; because of the malthusian catastrophe. Darwin thought this could be happening with all living things.
Malthusian Catastrophe: War, famine, plague. Why the population stays constant
define and describe artificial selection. Describe how artificial selection in domestic pigeons influenced darwins thinking
Artificial Selection: breeders choose mating pairs based on desired traits.
Darwin thought this could be happening in the natural world…natural selection.
Describe the independent discovery of evolution by natural selection by wallace and his copresentation and copublication with darwin
They both had the same ideas and decided to write and manuscript together to the Royal Society and co publish it later on.
Define and Describe priority with regard to scientific discovery
Priority is given to the first person to make a discovery or publish a theory.
identify and describe the components of darwins theory of evolution by natural selection
- Genetic Variation: there is a variety of phenotypes per trait (hair color, skin color)
- Heredity: traits are heritable
- Overproduction and competition: More offspring are being born than will reproduce and finite resources
- Differential reproduction: some reproduce more than other, which makes those traits more common.
describe the importance of the galapagos finches in the development of darwins theory
He was able to observe a variety of traits that each finch had acquired to adapt to their niche. They adapted to new environments.
Describe the grant and grants studies of galapagos finches and their conclusions
They observe beak size. The average was larger in dry years and smaller in wetter years due to size of seeds.
Concluded that natural selection can occur rapidly.
describe fossil evidence for evolution. Define transitional fossil. Describe archaeopteryx and tiktaalik as examples of transitional fossils
Transitional Fossil: a fossil with characteristics of both its ancestors and its descendants.
Fossils show evolution of a species over time.
Archaeopteryx represents todays birds with reptiles. Tiktaalik represents fish and amphibians.
describe evidence for evolution from comparative anatomy. Define and compare homologous vs analogous structures
homologous: similar anatomy due to similar embryonic origin.
analogous: same function but have different structure and embryonic origin
homologous structure shows common ancestry between organisms due to similar embryonic development. Analogous structure demonstrate convergent evolution (two species adapt to solve a problem the same way)
describe evidence for evolution from comparative embryology. Identify and describe the two structures found in all vertebrate embryos covered in class
pharyngeal pouch and postanal tail
similarities in embryonic development show common ancestry.
describe molecular evidence for evolution, including examples from cytochrome c, hemoglobin, and the GLO gene
Few mutations occur
Cytochrome C: regularly accumulates mutations the further away from humans. Shows time since divergence.
Hemoglobin: Also reflects time since divergence
GLO gene: gene has been reactivated in some species.
identify and describe common misconceptions about evolution. Explain why they are incorrect.
- Evolution is just a theory: misunderstanding of the world theory.
- Violates the second law of thermodynamics: evolution is in open system.
- fossils don’t represent intermediates
- mathematically improbable: probability is not an actual observation.
- evolution drives to perfection: selects traits based on adaptability.
- causes needed traits to appear: mutation appears at random.
describe the modern synthesis of evolutionary biology and how evolution is defined according the modern synthesis
modern synthesis blended inheritance with evolution to better understand evolution at the molecular level. evolution can now be defined quantitatively due to Mendel’s calculations.
describe hardy-weinburg equilibrium. Identify and describe the assumptions of Hardy-Weinburg equilibrium.
Allele frequencies remain constant (recessive don’t disappear and dominant don’t take over.) as long as certain assumptions are met
Assumptions:
1. large population
2. random mating
3. no mutation
4. no gain or loss of alleles through migration
5. no selective pressures
Under the equilibrium, allele frequencies and genotype frequencies add up to 100%.
Describe how mutation produces evolutionary change
Mutation introduces new alleles.
Describe how migration produces evolutionary change. Define and compare immigration vs. emigration
Migration transfers alleles to different locations. Changes allele frequencies.
describe how genetic drift produces evolutionary change. Describe founder effect and bottleneck as examples of genetic drift mechanisms
genetic drift is random changes in allele frequencies. This can add too or remove a gene pool.
Founder effect: smaller population stems from a larger and shows less genetic variability.
Bottleneck: population declines drastically and then recovers causing less genetic diversity (natural selection)
Describe how nonrandom mating, including inbreeding, produces evolutionary change.
Nonrandom: influences allele frequencies
inbreeding: doesn’t mix traits. Amplifies negative traits.
describe how selection produces evolutionary change. Define and compare stabilizing, directional, and disruptive selection
stabilizing: favors intermediate phenotype (birth weight being similar to that of parents)
Disruptive: favors phenotype extremes, no intermediate.
Directional: distribution is pushed in direction.
Define and describe heterozygote advantage and industrial melanism in terms of selection. Identify and describe examples of each
Industrial Melanism: easier to see/stand out and don’t survive as well. These organisms have more melanin than the typical color scheme. Peppered moth example.
Heterozygote Advantage: Heterozygote has a higher fitness than homozygote. Example, sickle cell trait protects against malaria in heterozygotes and causes the disease on homozygotes.
Describe the endler guppy experiments and their conclusions
Guppies were placed in pools. 2 had no predators, 8 had two kinds. Guppies with pike were smaller and drab. Guppies with killifish were larger and more colorful.
Transplanted guppies from lower to upper became colorful. Predators drive selection.
Define speciation. Identify and describe the three concepts used to define species that were discussed in class. Define and compare allopatric vs sympatric speciation
Speciation: population splits and becomes 2 interbreeding populations (allopatric is geographical separation and sympatric is no geographical separation)
typological, biological, and phylogenetic
Biological: Species mate with like species (reproductive isolation)
