Biology Unit 2 Test Prep

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Questions and Answers

Which event would indicate that evolution has occurred?

A white-eyed fly is born into a population of brown-eyed flies

An animal gets fat

An allele frequency changes in a population (correct)

A new predator comes into an environment

Which situation would most likely result in evolution?

An alligator has no alleles for scales

A predator prefers one phenotype to another (correct)

A single individual joins a large population

A large population loses a few individuals

Which group of organisms is classified as a population?

All dogs in China

Different kinds of butterflies living in the same patch of rain forest

A group of skunks living in the same forest (correct)

Robins in North America

Which group of alleles can be considered the gene pool of white-tailed deer in Michigan?

All alleles of the white-tailed deer in this population only Signup and view all the answers

Which statement about lethal genes is most accurate?

They can be maintained in a gene pool by heterozygous carriers when the allele is recessive and the individuals reproduce. Signup and view all the answers

Which statement must be true about traits acted upon by natural selection?

The trait is passed on genetically to the next generation. Signup and view all the answers

Which statement is most likely true about a population experiencing disruptive selection?

Two different shell patterns are increasing in frequency, while the most common pattern is decreasing. Signup and view all the answers

Which general statement can be made about Georges Cuvier's studies?

Through specific studies, new ideas can be developed. Signup and view all the answers

Why was Charles Darwin able to offer a large amount of evidence for his theory of evolution by natural selection?

He collected data for 5 years while traveling around the world. Signup and view all the answers

How does comparing the embryos of different organisms support the theory of evolution?

The stages of development of the embryos of different organisms are extremely similar, thereby suggesting common ancestors. Signup and view all the answers

What supports the theory of evolution regarding a bird's wing, a dolphin's flipper, and a cat's paw?

They are evidence that the animals had a common ancestor. Signup and view all the answers

Which sentence best describes vestigial structures?

They may have had an important function in the past. Signup and view all the answers

How could comparing amino acid sequences support the theory of evolution?

Comparing amino acid sequences can show close genetic relationships between organisms that may appear very different, such as whales and hippos. Signup and view all the answers

Which statement names a significant benefit of studying fossils?

Fossils give information about the time period in which organisms lived in the past. Signup and view all the answers

How does radiometric dating help scientists pinpoint the age of a fossil?

Radiometric dating shows the rate of decay of radioactive material present in any object. Scientists can use that data to find the absolute age of the fossil. Signup and view all the answers

Natural selection would most likely work best in which of the scenarios below?

A population of salmon with different skin colors that attract mates. Signup and view all the answers

In a population of owl monkeys, allele T (TT and Tt) codes for tufted tails. The frequency of allele t (tt), which codes for nontufted tails, is 40 percent. If a new predator starts catching the monkeys by their tufts and natural selection occurs, which outcome would most likely happen over time?

The frequency of allele T would decrease and the frequency of allele t would increase. Signup and view all the answers

According to the Hardy-Weinberg principle, if p and q are unchanging in a population, the population is in equilibrium. Which type of population does this scenario represent?

A population with constant allele frequencies. Signup and view all the answers

Which main change can happen in a small population that is the direct result of genetic drift?

Large changes in allele frequencies can occur in a short time. Signup and view all the answers

In which area would a population be geographically isolated?

An island Signup and view all the answers

Study Notes

Key Concepts in Evolution and Genetics

Evolution is indicated by changes in allele frequency within a population.
Natural selection is a key mechanism of evolution, acting on existing traits that are genetically inherited.
Evolutionary changes are more pronounced when a predator favors one phenotype over another.

Population and Gene Pool

A population consists of individuals of the same species in a specific area, e.g., skunks in a forest.
The gene pool represents all alleles present within a population, specifically the alleles of that population alone.

Gene Dynamics

Lethal alleles can persist in a gene pool when carried by heterozygous individuals that do not express the trait.
Traits subject to natural selection must be genetically inherited and can impact survival and reproduction.

Selection Types

Disruptive selection leads to two distinct phenotypes becoming more common, reducing a previously dominant phenotype.
Stabilizing selection is not explicitly mentioned, but it generally favors intermediate phenotypes.

Fossil and Comparative Studies

Fossils provide insights about organisms’ past existence and the eras they inhabited.
By comparing embryos of different species, scientists conclude shared ancestry due to similar developmental stages.
Cuvier’s work suggests that new scientific ideas arise through careful examination of historical biological data.

Charles Darwin and Evidence for Evolution

Darwin gathered extensive evidence for his theories over a five-year global expedition.
Homologous structures, such as wings and flippers, substantiate evolutionary relationships, indicating common ancestry.

Vestigial Structures

Vestigial structures are remnants that may have served a purpose in ancestral species but are less functional in current organisms.

Genetic Comparisons

DNA and amino acid sequencing reveal genetic relationships that support evolution, even among seemingly different species like whales and hippos.

Radiometric Dating

Radiometric dating measures the decay of radioactive isotopes to determine a fossil's absolute age.

Population Genetics

The Hardy-Weinberg principle describes a population model where allele frequencies remain constant, signifying genetic equilibrium in a stable environment.
In small populations, genetic drift can lead to rapid changes in allele frequencies due to random events.

Geographic Isolation

Geographic isolation occurs in defined areas, such as islands, creating opportunities for separate evolutionary pathways.

Summary of Natural Selection Scenarios

Natural selection is most effective when variations, such as differing coloration in mating signals, exist within a population.

This compilation encompasses foundational themes of evolution, population genetics, and evidence supporting the theory, critical for understanding biological diversity and change over time.

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Prepare for your Biology Unit 2 final exam with these flashcards. Focus on key concepts related to evolution, allele frequency changes, and significant events indicative of evolutionary processes. Enhance your understanding and retention of critical biological principles.