Biology Ch. 17-18 Test(AT) Flashcards
_____ Also called selective breeding.
Artificial selection
_____The ability of an organism to survive and reproduce in its environment.
Fitness
_____The type of genetic drift that follows the colonization of a new habitat by a small group of individuals.
Founder’s effect
_____The separation of populations by barriers such as rivers, mountains, or bodies of water is called.
Geographic isolation
_______The genes carried by all members of a particular population.
Gene pool
_____When allele frequencies in the gene pool of a population remain constant.
Genetic equilibrium
_____When fitness causes changes in the inherited characteristics of a population over time.
Natural selection
_____Any change in the genetic code.
Mutation
_____When distantly related organisms independently evolve similar traits to adapt to similar necessities.
Convergent evolution
_____Contributes to bacteria developing antibiotic release.
Lateral gene transfer
____The formation of new and distinct species in the course of evolution.
Speciation
_____Change over time.
Evolution
_____How many times an allele occurs in a gene pool.
Allele frequency
_____A characteristic that increases an organism’s fitness.
Adaptation
Who were Hutton and Lyell? How did their theories help Darwin?
Hutton and Lyell were geologists. Their theories provided a longer timeline for changes to take place. They also supported the idea that Earth has changed since its creation and we can observe the process and history of changes with evidence.
Who was Lamarck, what was his theory? Which parts were accepted, which parts weren’t accepted?
Lamarck proposed “Use and disuse” and acquired characteristics as a means for evolution. Accepted: traits impact fitness and evolution happens. Not accepted: Acquired traits don’t get passed to offspring.
How would Lamarck’s theory explain the evolution of long neck giraffes?
Giraffe necks became longer because they were reaching for leaves higher in the trees.
What were the three patterns of diversity that Darwin described? Provide an example for each.
Species vary globally: large flightless birds, emu, rhea, ostrich
Species vary locally: Isabella island vs. Hood island tortoise
Species vary over time: armadillo vs Glyptodont fossil
When Darwin presented his theory, what did most people think about the age of the earth?
Most believed the earth was only a few thousand years old.
What was Thomas Malthus’ theory? Why was this important to Darwin?
Malthus proposed that human population would outgrow resources and cause war, famine, and disease. Darwin agreed and could apply this to the struggle to survive for all life.
Give an example of artificial selection.
When humans breed dogs, cows for milk production, etc.
Why did Darwin wait so long to publish his theory?
He was afraid of backlash and how it would be accepted.
What causes competition between organisms?
Limited resources such as space, food, and mating opportunities.
Describe how Darwin says natural selection causes evolution to occur.
Nature selects the best adaptations for survival (ones that increase fitness). As nature selects adaptations, those traits are passed to offspring at an increasing rate. This causes slow, incremental changes to a species.
What conditions must exist for natural selection to take place?
Traits are inherited; resources are limited (struggle for existence); natural variations in species.
What is descent with modification?
Each living species has descended, with changes, from other species over time.
Define Homologous, Analogous, and Vestigial Structures. Give examples of each.
- Homologous structures - have somewhat different mature forms and function but develop from the same embryonic tissues. Ex: Turtle leg
- Analogous structures - structures that are different in form but similar in function. Ex: wing of bat
- Vestigial structures - traces of homologous organs in other species. Ex: legs
How does embryology support common ancestry?
Early stages in embryonic development are similar among animals with backbones, suggesting they have a common ancestor.
A change in allele frequency indicates a population that is_______.
Evolving
What are the sources of genetic variation?
Mutations, genetic recombination from sexual reproduction, lateral gene transfer.
Why don’t all mutations cause evolution?
Some mutations don’t get passed on, only mutations passed through sperm or egg cells. Also some mutations can decrease or not change fitness rather than increasing it.
The number of phenotypes produced for a trait depends on how many ________ control the trait.
genes
Similarities in ________, RNA and proteins (amino acid sequences) indicate a common ancestor.
DNA
________ mutations are commonly studied by researchers interested in molecular clocks.
Neutral
True or false - The dominant gene is always the most common in a population.
False
What is directional selection? Provide an example.
Individuals at one end of the curve have a higher fitness than individuals in the middle or at the other end. EX: Finches with large beaks being favored.
What is stabilizing selection? Provide an example.
Individuals near the center of the curve have a higher fitness than individuals at either end. EX: Mass of human infants at birth
What is disruptive selection? Provide an example.
Individuals at the outer ends of the curve have a higher fitness than those near the center. EX: bird population where medium sized seeds become uncommon
Random change in allele frequency is called _______.
Genetic drift
How does a bottleneck impact genetic diversity?
It reduces genetic diversity.
The founder effect is the result of ________.
migration
What conditions disturb genetic equilibrium?
Nonrandom mating, small populations, immigration and emigration, mutations, natural selection.
What are the 3 main ways populations can become reproductively isolated?
Behavioral, geographical, and temporal isolation.
________ use mutation rates to estimate the time two species have been evolving.
Molecular clocks
The Hardy-Weinberg equation is represented by two equations. What are they? What do they test for?
p^2 + 2pq + q2 = 1 - tests for frequency for of genotypes
p + q = 1 - tests for frequency of alleles
How is genetic equilibrium different from genetic drift?
Genetic drift is random and changes allele frequencies. Genetic Equilibrium occurs when allele frequencies are not changing.
