biology 101 exam 2

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When light hits a rhodopsin molecule..: na+ channels close, hyper polarizing the cell and causing the release of less glutamine.
What is evolution?: A change in the frequency of traits (and the underlying genes) in a population of a species over generations.
uniformitarianism: Geological processes function today same as they did in the past.
Natural Selection: ⬢ Variation ⬢ Heritability ⬢ Differential Reproduction
cumulative selection: For a population to evolve complex traits, each step of the evolution of the traits must confer an advantage on those that have it.

ex: insect wings evolved from movable gill plates. middle stages allowed insects to glide on water
Counterargument 2 imperfections in nature: lizards who pseudo copulate before they can fertilize their own eggs
homology: Similarity due to inheritance from a common ancestor
ex: forearm skeleton
convergent evolution: Some similarities are analogies, not homologies.
Due to common environmental pressures, not common inheritance.
Superficially similar features evolve independently, and do NOT indicate evolutionary relatedness.
4 parts of natural selection: 1. variation
2. heritability
3. some individuals produce more offspring due to adaptations (higher fitness)
4. differential reproduction
darwinian fitness: the ability of an individual to survive and reproduce. Measured in terms of relative reproductive success.
adaptation: a heritable trait helps an individual to survive and reproduce.
i.e. that increases the fitness of an individual relative to other individuals.
selection pressure or agent of selection: The natural or anthropogenic force that affects an individualâ€™s survival and reproduction. Examples include predators, soil moisture, plant toxins, and parasites.
Evidence of Evolution : Fossils Extinction: Darwin used the idea of extinction as evidence because if species have gone extinct, then they have changed through time
Evidence of Evolution : Fossils Transitional forms: a fossil species with traits that are intermediate between older and younger species

showed change through time
law of succession: resemblances between fossils and living animas in the region where the fossils were found
Evidence of Evolution : Fossils Environmental Change: theory of plate tectonics

fossils found above sea level, but was once an ocean

if the earth itself has changed. it is logical to think that organisms have changed as well
Evidence of Evolution : living species Vestigial traits: reduced or incompletely developed structures that have no function, or reduced function but are similar to functioning organs or structures in other species

populations change in response to their environments
Evidence of Evolution : living species Homologies: darwin used this as evidence; if vertebrates had a common ancestor and is that ancestor had a limb with the same ground plan, then it would be logical to infer that its descendants had modified forms of the same design
phylogenic tree: a branching diagram that describes the relationships among species
contraints on adaptations: genetic correlation

Finches beak:
ideal = narrow+deep
but deep and wide correlate so that was the best option
Test A light-receptor cell becomes hyperpolarized in response to a flash of light. What explains why this occurs?: the light promotes the closing of sodium ion channels
test What it the pathway of light through the vertebrate eye?: cornea, iris, pupil, lens, retina
what role does the iris play in the vertebrate eye?: controls the amount of light entering the eye
test A farmer uses triazine herbicide to control pigweed. This works well for a few years, but after a few years the farmer sees more and more pigweed. Why?: only triazine-resistant weeds survived and reproduced, so each year more and more pigweed was triazine-resistant
test A farmer uses triazine herbicide to control pigweed. This works well for a few years, but after a few years the farmer sees more and more pigweed. What will solve the farmers problem?: trying a different herbicide
test What is the best modern definition of evolution?: change in allele frequencies in a population over time
test What would you expect to observe if a population of medium ground finches that colonizes an island where tribulus cistiodes is the primary available food?: evolution of yet larger deeper beaks over time
test Tourist come to the island where the finches colonized, and set up bird feeders with various seed sizes in order to better see the birds. What is most likely to happen to the beaks of the finches?: increased variation in beak size and shape over time
Test Evolution by natural selection changes the population but not the individual: true
Test vestigial traits and neutral changes in DNA sequences are good examples of: nonadaptive traits
Test Which category of evidence most convincingly disproves the theory of special creation?: the fossil record
Test A molecular biologist studying fungi discovers a gene family that is similar to a gene family known in the fruit fly. If she wants to determine whether the fungi and fruit fly gene families are analogous or homologous she should:: see if the organisms in lines that branched off between the fungi and insects have similar gene families
test How can Darwinian fitness be estimated?: count the number of offspring produced by different individuals in a population
test Why dose the presence of extinct and transitional forms in the fossil record support the pattern component (descent with modification) of the theory of evolution by natural selection?: its support the hypothesis that species have changed over time.
test Why are homologous traits similar?: they are derived from a common ancestor
test What changes, populations or individuals due to natural selection?: populations~not individuals~ change when natural selection occurs
Test Why did Darwin document and describe vestigial traits?: vestigial traits indicate that species change over time, This is an important pattern component of the theory of evolution, but is inconsistent with the theory of special creation
Test What is the best definition of Darwinian fitness?: darwinian fitness is the ability of an individual to survive and reproduce relative to other individuals
Test Rifampin resistance: rifampin resistance is a heritable trait that increases the fitness of individuals compared to susceptible individuals
test Resistance to a wide variety of insecticides, fungicides, antibiotics, antiviral drugs, and herbicides has recently evolved in hundreds of insects, fungi, bacteria, viruses, and plants. Why?: humans are altering the environments of these organisms, and the organisms are evolving by natural selection
Test Evolutionary constraint in medium ground finches: genetic correlation between beak depth and width in medium ground finches
test Synonymous vs non-synonymous ratios should be 1:3, but are actually 3:1. Why?: purifying selection shifts the ratio in natural populations
Test Both morphological and genetic evidence supports the idea that primates are our closest evolutionary ancestors. What species is our closest relative?: chimpanzee

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