BIO 199- Review questions

In a population of seahorses, red seahorses on average produce 125 offspring and brown seahorses produce 75 offspring. What is the fitness of the brown phenotype?

0.6 (Remember that the most fit phenotype is assigned a fitness value of 1. In this case the red seahorses will have a fitness of 1 and the brown seahorses will have a fitness of 75/125, or 0.6.)

Which of the following are reasons why island trees belong to plant families that typically do not have tree members (for example the sunflower family)?

1. The tree niche is empty and so a flower can evolve through natural selection to be tree-like 2. Tree seeds rarely make it to isolated islands

It is most likely that Earth's first organisms emerged and lived at very high temperatures about how many years ago?

3.8 BYA

Structures that have evolved separately but look very similar exhibit ________ evolution; in contrast, structures that evolved through modification from a common ancestral trait are ______ structures.

Convergent : Homologous

When populations are only partially reproductively isolated, which of the following may occur?

Despite prezygotic and postzygotic isolating mechanisms, some individuals may survive and reproduce.

Which of the following is true of evolutionary forces in natural populations?

Evolutionary forces can alter the allele frequencies in a natural population.

What term quantifies reproductive success of a phenotype?

Fitness

Which of the following describes when single-celled organisms were the only form of living organisms?

For most of the history of the Earth

According to the theory of blending Inheritance, offspring were expected to be phenotypically __________ relative to their parents, which would dilute any new genetic variants.

Intermediate

Structures that are derived from a common ancestor but with different appearance and function are called _________ structures, while _________ structures refers to structures that have little or no function but are functional in an ancestor.

Homologous : Vestigial

The forelimbs of vertebrates are an example of _______ structures, while the human appendix is an example of a _______ structure.

Homologous: vestigial

Under which of the following scenarios is early life on Earth least likely to have arisen?

In an ice-covered ocean during a Snowball Earth event

Early life may have arisen during the Archean, but evidence of life in the form of microfossils is difficult to interpret for which reason?

Non Biological processes can produce microfossil-like structures

What is meant by the term allopatric?

Occurring in geographically separated areas

Early systematics (before the advent of molecular sequencing) was based on overall________ between species.

Similarities

Genetic drift has a greater impact on which of the following?

Smaller populations

When little or no evolutionary change in a species occurs for a long time, that time period is known as which of the following?

Stasis

Species that are _______ species occur in the same location and are phenotypically different.

Sympatric

________________ is the study of evolutionary relationships among organism

Systematics

The science of classifying organisms is termed

Taxonomy

Today, fossils have been found that link

All major groups of vertebrates

How do postzygotic isolating mechanisms prevent successful interspecies hybridization?

Although fertilization is successful, the resulting hybrid is unable to develop or reproduce.

Which of the following best describes the general trend in global species diversity over time?

An overall increase, but with some some sharp declines occurring at certain times

A ______ is a shared character state that was not inherited from a common ancestor. These characters can make two species seem related when they are actually not.

homoplasy

In cladistics, a(n) __________ is any aspect of the phenotype, including morphology, physiology, behavior, and DNA.

character

According to the phylogenetic species concept, a species is a population that

it has evolved independently of other groups of populations

Changes in allele frequencies within a population may result from ______ , which are changes in the nucleotide sequences of an organism's DNA.

mutations

Under the PSC (phylogenetic species concept)

populations with slight differences could be recognized as distinct species.

Derived Characters are

shared with the most recent common ancestor of a group, but not with prior ancestors.

The diversification of Drosophila species in the originally vacant niches and frequently isolated habitat patches of the Hawaiian Islands is an example of which of the following?

Adaptive Radiation

Organic molecules which are clearly of biological origin are called

Biomarkers

The process of categorizing species and determining where they belong in the taxonomic hierarchy is known as ______.

Classification

What types of conditions may lead to adaptive radiation?

Formation of islands through volcanic activity and subsequent colonization A species occurs in an environment with few other species and many resources A catastrophic event leading to mass extinction

Which of the following agents of evolutionary change occurs when alleles move from one population to another?

Gene flow

The processes that lead to evolutionary change are mutations, natural selection,_________ drift, gene flow and _________ mating.

Genetic ; Nonrandom

What process can promote speciation through random changes between isolated populations?

Genetic Drift

Select the observations that would indicate that a population is deviating from Hardy-Weinberg equilibrium.

Genotype frequencies do not match those predicated by the Hardy-Weinberg equation based on existing allele frequencies. Allele frequencies are changing between generations.

Assortative mating changes ______ frequencies but does not change ______ frequencies.

Genotypes: Alleles

The concept of ______ suggests that each new species evolves continuously over time.

Gradualism

The first 500-700 million years of Earth's history comprised an eon called which of the following?

Hadean Eon

Geographic isolation can accelerate speciation due to which of the following reasons?

It restricts gene flow

Hardy-Weinberg equilibrium requires that the population size is ______ and mating is __________

Large : random

Which method is used to infer the timing of branching events by using the fossil record or geologic events to calculate DNA divergence rates?

Molecular Clock

What is the ultimate source of all new alleles?

Mutations

What process may lead to speciation when a population adapts to its environment in such a way that it becomes reproductively isolated from other populations?

Natural Selection

Economically important organisms that have been modified significantly through artificial selection include

Pigs, cattle and corn

As a result of convergent evolution, many marsupial mammals of Australia look similar to ___________ mammals found elsewhere and occupy a similar ecological niche.

Placental

___________ is the state of a cell or organism having more than two paired sets of chromosomes.

Polyploidy

One consequence of mass extinctions is that dominant species may go extinct, allowing other species to undergo adaptive ________to use the newly freed resources.

Radiation

__________ ___________ is the key to the process of speciation.

Reproductive isolation

Relative dating

Rocks are based on their position

Absolute dating

Rocks are dated based on their isotopic composition.

Which characteristic of cichlids enabled them in their evolutionary radiation?

Second set of functioning jaws

Outside of mass extinctions, how has the rate of speciation compared to the rate of extinction over the past 600 million years?

The rate of speciation has surpassed the rate of extinction.

Which of the following is true about transitional fossils (choose all that apply)?

They help to fill in the gap in the fossil record between two separate groups. They illustrate how major transitions in life occurred.

How are traits produced by convergent evolution different from homologies?

Traits produced by convergent evolution have not evolved from a common ancestral trait, while homologies have.

True or false: Natural selection does not always produce perfectly working adaptations, because it can only work on the genetic variation present in a population.

True

True or false: Populations of a single species that connect those that are more geographically separated are often intermediate phenotypically when compared to the separated populations.

True

Select all of the following criteria that must be present for natural selection to occur and cause evolutionary change in a population.

Variation must result in differences in the number of offspring surviving in the next generation. Variation must have a genetic basis. Variation must exist among individuals

In all cases when scientists have performed artificial selection experiments on fruit flies, a strong and predictable __________ response has occurred

evolutionary