BIO Ch 8

Natural selection stems from the observation that some individuals in a population survive longer and have more offspring than others, thus passing on more of their genes to the next generation. For example, a big powerful male gorilla is much more likely than a smaller weaker gorilla to become the population's silverback (pack leader who mates far more than other males in the group). Pack leader will, therefore, father more offspring who share half his genes and are likely to also grow bigger like father. Over time, the genes for bigger size will increase in frequency in the population, and the population will, as a result, grow larger on average

Describe natural selection and give an example of it at work in a population.

a population's allele frequencies are inherently stable. Unless an evolutionary force is acting upon the population, the population would carry the same genes at the same frequencies generation after generation, and individuals would, as a whole look essentially the same

Explain the Hardy-Weinberg principle of equilibrium

The statement implies that there's a goal to evolution and that the monkey represents greater progress to that goal than the mouse. Both species are likely well adapted to their particular environment, which is the outcome of natural selection

Explain why the statement that a monkey is more evolved than a mouse is incorrect.

c. gene flow

Galápagos medium ground finches are found in Santa Cruz and San Cristóbal islands, which are separated by about 100km of ocean. Occasionally, individuals from either island fly to the other island to stay. This can alter the allele frequencies of the population through which of the following mechanisms? a. natural selection b. genetic drift c. gene flow d. mutation

In science, a theory is a thoroughly tested and verified set of explanations for a body of observations of nature. It's the strongest form of knowledge in a science. In contrast, a theory in common usage can mean a guess or speculation about something, meaning that the knowledge implied by the theory may be very weak.

How does the scientific meaning of "theory" differ from the common, everyday meaning of the word.

plants that can best use the resources of the area, including competing with other individuals for those resources, will produce more seeds themselves and those traits that allowed them to better use the resources will increase in the population of the next generation

If a person scatters a handful of plant seeds from one species in an area, how would natural selection work in the situation?

b. mutation and gene flow

In which of the following pairs do both evolutionary processes introduce new genetic variation into a population? a. natural selection and genetic drift b. mutation and gene flow c. natural selection and gene flow d. gene flow and genetic drift

a. how allele frequencies change in a population over time

Population genetics is the study of ______. a. how allele frequencies change in a population over time b. populations of cells in an individual c. the rate of population growth d. how genes affect embryological development

d. descent with modification

The fact that DNA sequences are more similar in more closely related organisms is evidence of what? a. optimal design in organisms b. adaptation c. mutation d. descent with modification

c. homologous structures

The win of a bird and the arm of a human are examples of ______. a. vestigial structures b. molecular structures c. homologous structures d. analogous structures

a. fact

The word "theory" in theory of evolution is best replaced by ______. a. fact b. hypothesis c. idea d. alternate explanation

It's likely the two species would start to reproduce with each other if hybridization is still possible. Depending on viability of their offspring, they may fuse back into one species

Two species of fish had recently undergone sympatric speciation. The males of each species had a different coloring through which females could identify and choose a partner from her own species. After some time, pollution made the lake so cloudy it was hard for females to distinguish colors. What might take place in this situation?

c. Microevolution describes the evolution of populations, while macroevolution describes the emergence of a new species over long periods of time.

What is the difference between micro- and macroevolution? a. Microevolution describes the evolution of small organisms, such as insects, while macroevolution describes the evolution of large organisms, such as people and elephants. b. Microevolution describes the evolution of microscopic entities such as molecules and proteins, while macroevolution describes the evolution of whole organisms. c. Microevolution describes the evolution of populations, while macroevolution describes the emergence of a new species over long periods of time. d. Microevolution describes the evolution of organisms over their lifetimes while macroevolution describes the evolution of organisms over multiple generations.

b. One involves the movement of the organism, whereas the other involves a change in the environment

What is the main difference between dispersal and vicariance? a. One leads to allopatric speciation whereas the other leads to sympatric speciation b. One involves the movement of the organism whereas the other involves a change in the environment c. One depends on a genetic mutation occurring, whereas the other does not. d. One involves closely related organisms, whereas the other involves only individuals of the same species.

b. natural selection

What scientific concept did Charles Darwin and Alfred Wallace independently discover? a. mutation b. natural selection c. overbreeding d. sexual reproduction

d. all of the above

Which of the following situations will lead to natural selection? a. The seeds of two plants land near each other and one grows larger than the other. b. Two types of fish eat the same kind of food, and one is better able to gather food than the other. c. Male lions compete for the right to mate with females, with only one possible winner. d. all of the above

a. A flood causes the formation of a new lake

Which situation would most likely lead to allopatric speciation? a. A flood causes the formation of a new lake b. A storm causes several large trees to fall down. c. A mutation causes a new trait to develop. d. An injury causes an organism to seek out a new food source.

b. longer distance between divided groups

Which variable increases the likelihood of allopatric speciation taking place more quickly? a. lower rate of mutation b. longer distance between divided groups c. increased instances of hybrid formation d. equivalent numbers of individuals in each population

b. there are no viable scientific alternatives

Why are alternative scientific theories to evolution not taught in public school? a. more theories would confuse students b. there are no viable scientific alternatives c. it is against the law d. alternative scientific theories are suppressed by the science establishment

Organisms of one species can arrive to an island together and then disperse throughout the chain, each settling into different niches, exploiting different food resources, and, evolving independently with little gene flow between different islands

Why do island chains provide ideal conditions for adaptive radiation to occur?

A vestigial structre is an example of a homologous structure that has been reduced through evolution to a non-functional state because its function is no longer utilized by the species exhibiting it; therefore, any mutations which might reduce its structure are not selected against. The fact that the species has vestiges of the structure rather than no structure at all is evidence that it was present in an ancestor and evolved to non-functionality through accumulation of random mutations

Why do scientists consider vestigial structures evidence for evolution?

macroevolution

a broader scale of evolutionary changes seen over paleontological time

speciation

a formation of a new species

adaptation

a heritable trait or behavior in an organism that aids in its survival in its present environment

founder effect

a magnification of genetic drift in a small population that migrates away from a large parent population carrying with it an unrepresentative set of allels

inheritance of acquired characteristics

a phrase that describes the mechanism of evolution proposed by Lamarck win which traits acquired by individuals through use or disuse could be passed on to their offspring thus leading to evolutionary change in the population

vestigial structure

a physical structure present in an organism but that has no apparent function and appears to be from a functional structure in a distant ancestor

sympatric speciation

a speciation that occurs in the same geographic space

allopatric speciation

a speciation that occurs via geographic separation

adaptive radiation

a speciation when one species radiates out to form several other species

homologous structure

a structure that is similar because of descent from a common ancestor

analagous structure

a structure that is similar because of evolution in response to similar selection pressures resulting in convergent evolution, NOT because of descent from a common ancestor

gene pool

all of the alleles carried by all of the individuals in a population

dispersal

an allopatric speciation that occurs when a few members of a species move to new geographical areas

vicariance

an allopatric speciation that occurs when something in the environment separates organisms of the same species into separate groups

divergent evolution

an evolution that results in different forms in two species with a common ancestor

convergent evolution

an evolution that results in similar forms on different species

microevolution

the changes in a population's genetic structure (i.e., allele frequency)

genetic drift

the effect of chance on a population's gene pool

gene flow

the flow of alleles in and out of a population due to the migration of individuals or gametes

natural selection

the greater relative survival and reproduction of individuals in a population that have favorable heritable traits, leading to evolutionary change

bottleneck effect

the magnification of genetic drift as a result of natural events or catastrophes

migration

the movement of individuals of a population to a new location; in population genetics it refers to the movement of individuals and their alleles from one population to another, potentially changing allele frequency in both the old and new population

modern synthesis

the overarching evolutionary paradigm that took shape by the 1940s and is generally accepted today

population genetics

the study of how selective forces change the allele frequencies in a population over time

variation

the variety of alleles in a population