Review of Concepts: Allele Frequency to Ecological Organization

Flashcards about allele frequency, reproductive isolation, genetic drift, mutations, and ecological organization.

What happens to the allele frequency of a harmful trait when acted upon by natural selection?

Natural selection acting on a harmful trait can cause the allele frequency of that trait to decrease over time.

What happens to the allele frequency of a beneficial trait when acted upon by natural selection?

Natural selection acting on a beneficial trait can cause the allele frequency of that trait to increase over time.

The frequency of an allele in a fly population changes from 89% to 20% after three generations. Which other events most likely occurred during the same time period?

An environmental change and a fly population decrease.

Scientists observed change in the distribution of tail lengths in a mouse population over time. At the genetic level, what has most likely happened to the allele for the shortest tail lengths?

The allele became less frequent than the alleles for longer tail lengths.

What is behavioral isolation?

Occurs when 2 populations of the same species develop differences in courtship or mating behaviors.

What is geographic isolation?

Occurs when 2 populations are separated by a geographic barrier.

What is temporal isolation?

Occurs when 2 populations reproduce at different times.

Two populations of the same species of seal live too far away to swim to allow mating. What type of isolation is this?

Geographic isolation

Species of birds have courtship dances. Females select the best dancers as mates. What type of isolation is this?

Behavioral isolation

Some trees produce pollen during different seasons, so they can't pollinate each other. What type of isolation is this?

Temporal isolation

What is genetic drift?

Random change in allele frequency in a small population due to chance.

How can the founder effect lead to changes in a gene pool?

Because a small, non-representative group starts a new population, altering allele frequencies and leading to a different evolutionary path.

In North America, the eastern spotted skunk mates in late winter, and the western spotted skunk mates in late summer. Even though their geographic ranges overlap, the species do not mate with each other. What most likely prevents these two from mating?

Reproductive Isolation

Which statement best describes how geographic isolation can contribute to speciation?

Geographic isolation physically separates populations and prevents them from interacting.

How can mutations in DNA lead to changes in one's genotype and phenotype?

Mutations in DNA alter the sequence of nucleotides in a gene, affecting protein production.

A mutation occurs in the genes that code for coat color in deer. Which change will most likely result from this mutation?

A change in the selection pressures acting on coat color

Which condition would most likely result in an increase in the phenotypic variation within a population?

A mutation leads to individuals with genetic differences.

What is a homologous structure?

Body structures shared by related species that have similar structures but different functions

What is an example of homologous structure?

forelimbs of humans, bats, and whales

What is an analogous structure?

Body Parts in different species that are similar in function but not Structure

What is an example of analogous structure?

wings of insects and birds

What is a vestigial structure?

Body parts inherited from ancestors but have lost much of their function

What is an example of vestigial structure?

human appendix, wings of flightless birds

The diagram shows the forelimbs of three animals. Which statement best describes the bones in the animals?

Similar bones in different organisms may have different functions.

Based on the amino acid sequences (Human CCA TAG CAC CTA, Pig CCA TGT AAA CGA, Chimpanzee CCA TAA CAC CTA, Cricket CCT AAA GGG ACG), which two organisms are most closely related?

Human and Chimpanzee

An unknown organism is found in the forest and the amino acid sequence is sequenced as follows: CCA TGG AAT CGA. What kind of animal do you think this is?

Pig

Whales have vestigial femurs and pelvic bones. Which statement explains why the vestigial structures are most likely present in whales?

Whales evolved over time from ancestors that lived on land.

Describe the relationship between a hypothesis, an inference and a theory.

Hypothesis: If/then statement, testable guess. Inference: Conclusion based on evidence. Theory: Well supported explanation.

Which statement about a pond ecosystem is a testable hypothesis? (A. The frogs living in the pond represent a population. B. Water is an abiotic component in the pond ecosystem. C. If the fish are given more food, then they will be happier. D. If the frogs are startled, then they will jump into the water.)

If the frogs are startled, then they will jump into the water.

What is the definition of Species/Organism (level of ecological organization)?

An individual living thing

What is the definition of Population (level of ecological organization)?

A group of organisms of the same species living in the same area

What is the definition of Community (level of ecological organization)?

All the populations of different species living in the same area

What is the definition of Ecosystem (level of ecological organization)?

A community of living organisms and their non-living environment

What is the definition of Biome (level of ecological organization)?

A large geographic area with similar climate conditions and organisms

What is the definition of Biosphere (level of ecological organization)?

The sum of all ecosystems on Earth

Two gray wolves, Five moose, Several species of conifer trees, Large granite rock, Shallow pond. Which term best classifies all of the student's observations?

Ecosystem