BIO185

What are prokaryotes?

The first organisms to evolve

What is evolution?

Changes in DNA

What evidence exists to support evolution?

Comparing animal/insect lifespans, hemoglobin levels, and embryos

What are the two scales of evolution study?

Macroevolution (longer time frames) and microevolution (shorter time frames).

What is population genetics?

The study of genetic changes in populations.

What defines a population?

A group of individuals of the same species capable of interbreeding and producing fertile offspring.

What is a gene pool?

The sum of all alleles for all genes in a population.

What does P represent in allele frequency?

Frequency of the dominant allele (A).

What does Q represent in allele frequency?

Frequency of the recessive allele (a).

What is the Genotype Frequency Equation?

P^2 + 2PQ + Q^2 = 1

What does p^2 represent in genotype frequency?

Frequency of homozygous dominant genotype (AA)

What does 2pq represent in genotype frequency?

Frequency of heterozygous genotype (Aa)

What does q^2 represent in genotype frequency?

Frequency of homozygous recessive genotype (aa).

What is the Allele Equation?

P + Q = 1

What does Hardy-Weinberg Equilibrium imply?

A population’s allele and genotype frequencies are inherently stable.

What is the null hypothesis of microevolution?

Hardy-Weinberg Equilibrium.

What happens if observed frequencies differ from Hardy-Weinberg predictions?

The population is evolving.

How do you calculate q from q^2?

Take the square root of q^2.

What is the first step in using Hardy-Weinberg equations?

Determine the allele frequencies, dominant allele (p) and recessive allele (q)

What information is needed to calculate expected genotype frequencies?

Number of individuals with different phenotypes.

The only source of new alleles

Mutations

What introduces variation?

Genetic Mutation

Smaller populations have the ____ fluctuation (genetic drift )

most

Larger populations have the ______ fluctuation (genetic drift)

least

Which of these is true about a population in Hardy-Weinberg equilibrium?

Natural selection is not occurring in this population.

What is true about genetic drift?

In a large population, many more generations are required before the allele is eliminated or fixed

What does “Bottleneck” do?

It reduces genetic diversity by significantly decreasing population size.

What is similar between mutations and genetic drift?

They are both random processes.

Small Population of colonizers —→ Genetic Drift

Founder Effect

What is Founder Effect?

Founder effect occurs when a SMALL number of individuals establish a new population, leading to REDUCED genetic diversity and an increased chance of certain alleles becoming fixed.

Movement of alleles among populations

Gene Flow

Low Gene flow leads to

Evolution

Death Valley has resulted in many species of pupfish, each endemic to one pond, which resulted from…

Disruption in gene flow

Natural Selection is the same as Evolution

False

Which of the following is false about natural selection?

 

It explains how life started.

Which of the following has the effect of increasing the rate of evolution?

strong selective pressures

Aleles can be transferred through the movement of fertile individuals or gametes (pollen, migration, seed dispersal)

True

What are the requirements of Natural Selection?

All of the above

Organisms with favorable traits survive _____ and reproduce _____

longer, more

Natural Selection = ___________

Adaptation

Morphology, physiology, or behavioral trait that gives organisms an advantage to cope with the environment

Adaptation

Adaptations evolve based on need, for example, Giraffes evolved long necks because they needed to reach the tall leaves

False

How do adaptations evolve?

They have to exist as a phenotype with an underlying genotype

Acclimatization _____ evolution.

is not

Going to a high elevation location, mountains, since there’s thinner oxygen, your body produces fewer red blood cells.

Acclimatization

Shifts in an allele’s frequency in a consistent direction, so individuals at one end of a range of phenotypic variation become more common over time

Directional Selection

Selection that favors the intermediate phenotype

Stabilizing Selection

Intermediate phenotypes selected against, favors both phenotype extremes, and can lead to speciation

Disruptive Selection

Common traits are favored by selection

Positive frequency-dependent selection

Rare traits are favored by selection

Negative frequency-dependent selection

Predation in fish – the uncommon prey stands out and is eaten, while common prey gets to escape

Positive frequency-dependent selection

The rarer form of the parasite is more successful at biting the prey

Negative frequency-dependent selection

Which of the following is true about positive frequency-dependent selection?

It favors common traits.

Which process increases genetic variation?

heterozygote advantage

In most natural populations, individuals do not have an equal chance of mating

Non-Random Mating

The environment selects for traits that increase the likelihood of reproductive success

Sexual Selection

Variation in reproductive success is high in ____ and low in _____

males, females

Selection of a sex for the other sex, and often manifests in sexual dimorphism

Intrasexual Selection

To increase fitness, they should maximize the number of matings

Males

To increase fitness, they should maximize the quality of their offspring

Females

Natural selection affects sexual selection traits

True

_______ usually exhibit reversed sexual selection, while _______ usually do not exhibit sexual selection

Polyandrous species, Monogamous species

Is unselfish behavior or traits

Altruism

A vampire bat feeds another bat only if it’s received a meal from that bat before

Reciprocal Altruism

Natural selection favors traits that help relatives

Kin Selection

Personal reproductive success is measured as the number of offspring that survive and reproduce.

Direct Fitness

Reproductive success of relatives that share genes with the individual

Indirect Fitness

The total genetic contribution of an individual to the next generation

Inclusive Fitness

Which is a difference between sexual selection and natural selection?

Natural selection favors adaptive traits; sexual selection favors non-adaptive traits.

Kin selection favors traits that maximize both

inclusive fitness, indirect fitness

Which species concept would you use to determine the different species of bacteria that live in your large intestine? (All bacteria have one of three morphologies: round, rod-shaped, or spiral-shaped).

genetic

One species of cicada mates once every 13 years; another species of cicada mates once every 17 years. These two species live in the same habitat but do not interbreed. Which reproductive isolation separates the two species?

temporal

Downsides: It can be challenging to differentiate species that occupy the same habitat and perform similar roles in life

Ecological Species Concepts

Downsides: Individuals within a species may vary significantly in appearance due to environmental factors, making it hard to distinguish species based solely using…

Morphological Species Concept

Downside: Based on reproduction. Not everything has reproduction. Extinct organisms, fossils, etc

Biological Species Concepts

Reproductive seasons/periods are different

Temporal Isolation

When species are reproductively isolated from others due to differences in behavior

Behavioral Isolation

If physical parts of a species aren’t compatible

Mechanical Isolation

Important in aquatic organisms due to them squirting eggs and squirting out sperm into water

Gametic Isolation

Reduced Hybrid Viabilitys means…

Decreased likelihood of survival

Chance event physically separates population into subgroups

Geographic Isolation

Isolated populations begin to diverge due to mutation, genetic drift, and selection

Divergence

Eventually the two populations are genetically isolated from one another

Genetic Isolation

Sympatric Speciation is through _____, and are isolated ______, not ________

habitat specialization, genetically, geographically

Two groups of flys were raised for eight generations. One group fed maltose and the other fed starch. In the end, starch-based flies want to mate with starch-based flies, and maltose-based flies want to mate with other maltose-based flies

Reproductive Isolation

Sexual selection can lead to reproductive isolation and sympatric speciation

True

The formation of a new species without geographic isolation, occurring in the same habitat

Sympatric Speciation

Speciation due to geographic isolation (e.g., mountains, rivers, or distance separating populations)

Allopatric Speciation

Which of the following is false about genetic drift?

It introduces variation into a population.

Natural rate of extinction as environments change

Background Extinction

Large numbers of species and lineages die out over a short period

Mass Extinction

The rapid diversification of an ancestral species into many new forms

Adaptive Radiation

Suggests some traits evolved independently, not due to ancestral character or relationship, but due to convergent evolution

Homoplasy

This leads to the evolution of homologous structures

Divergence

This leads to the evolution of analogous characters

Convergence

An evolutionary unit that includes an ancestral population and all of its descendants but no others (also called a lineage, or clade)

Monophyletic Group

What is A? It’s definition is a shared, derived, trait

Synapomorphy

Similarity in organisms due to common ancestry

Homology

What is Group II?

Paraphyletic Group

What is Group III?

Polyphyletic Group