bio 30 unit d

What is a population?

A group of the same species living in the same place at the same time.

What is a gene pool?

All the alleles present in a population.

What is genetic equilibrium?

A state in which allele frequencies remain constant from generation to generation (no evolution).

What is the Hardy-Weinberg Principle?

If all conditions are met, allele frequencies in a population remain constant over time.

What are the two Hardy-Weinberg equations?

p + q = 1 and p² + 2pq + q² = 1.

What does p represent?

Frequency of the dominant allele.

What does q represent?

Frequency of the recessive allele.

What does p² represent?

Frequency of homozygous dominant individuals (AA).

What does 2pq represent?

Frequency of heterozygous individuals (Aa).

What does q² represent?

Frequency of homozygous recessive individuals (aa).

What are the five Hardy-Weinberg conditions?

Large population, random mating, no mutations, no migration, no natural selection.

Why is Hardy-Weinberg useful?

It predicts expected allele frequencies in a non-evolving population.

What indicates microevolution is occurring?

Observed allele frequencies differ from Hardy-Weinberg predictions.

How do you calculate p if q is known?

p = 1 - q.

How do you calculate q if q² is known?

q = √(q²).

If 1% of a population shows a recessive trait, what is q?

q² = 0.01, therefore q = 0.1.

If q = 0.4, what is p?

0.6.

What is mutation?

A change in DNA that introduces new alleles into a population.

Why are mutations important?

They increase genetic variation.

What are teratogens?

Agents that can cause mutations.

What is gene flow?

The movement of alleles between populations.

How does gene flow affect diversity?

It increases genetic diversity.

What is non-random mating?

Individuals choose mates based on certain traits rather than by chance.

What is inbreeding?

Mating between closely related individuals.

What is genetic drift?

Random changes in allele frequencies due to chance events.

Which populations are most affected by genetic drift?

Small populations.

What is the founder effect?

A new population is started by a small group carrying only part of the original gene pool.

What is the bottleneck effect?

A drastic reduction in population size decreases genetic diversity.

What is natural selection?

Individuals with advantageous traits survive and reproduce more successfully.

What is a heterozygous advantage?

When heterozygous individuals have higher fitness than either homozygous genotype.

What is population size?

The number of individuals in a population.

What is population density?

The number of individuals per unit area or volume.

Formula for population density (area)?

Density = Number of organisms ÷ Area.

Formula for population density (volume)?

Density = Number of organisms ÷ Volume.

What are the three population distribution patterns?

Random, uniform, and clumped.

What is a random distribution?

Individuals are spread without a predictable pattern.

What is a uniform distribution?

Individuals are evenly spaced, often due to competition.

What is a clumped distribution?

Individuals are grouped around resources or social structures.

What four factors affect population growth?

Births, deaths, immigration, and emigration.

What is natality?

Birth rate.

What is mortality?

Death rate.

What is immigration?

Movement of individuals into a population.

What is emigration?

Movement of individuals out of a population.

What is an open population?

A population where migration occurs.

What is a closed population?

A population where migration does not occur.

What is growth rate (GR)?

The change in population size over time.

What is per capita growth rate (CGR)?

The population growth per individual.

What does a positive growth rate indicate?

The population is increasing.

What does a negative growth rate indicate?

The population is decreasing.

What is biotic potential?

The maximum reproductive capacity of a population under ideal conditions.

What factors influence biotic potential?

Offspring number, reproductive frequency, survival rate, maturity age, and lifespan.

What is environmental resistance?

Factors that limit population growth.

Examples of environmental resistance?

Competition, disease, predation, lack of resources, climate.

What is carrying capacity (K)?

The maximum population size an environment can sustainably support.

What is exponential growth?

Rapid population growth when resources are abundant.

What does a J-shaped curve represent?

Exponential growth often followed by a crash.

What does an S-shaped curve represent?

Logistic growth that levels off at carrying capacity.

What are the four phases of a growth curve?

Lag, growth, stationary, and death.

What happens during the lag phase?

Population growth is slow.

What happens during the growth phase?

Births and immigration exceed deaths and emigration.

What happens during the stationary phase?

Births plus immigration equal deaths plus emigration.

What happens during the death phase?

Deaths and emigration exceed births and immigration.

What are density-independent factors?

Factors that affect populations regardless of size.

Examples of density-independent factors?

Droughts, floods, fires, temperature, storms.

What are density-dependent factors?

Factors whose effects increase as population density increases.

Examples of density-dependent factors?

Disease, parasites, competition, food shortages.

What is the Law of the Minimum?

The resource in shortest supply limits population growth.

What is Shelford's Law of Tolerance?

Too little or too much of an environmental factor can be harmful.

What are r-selected species?

Species that reproduce rapidly with many offspring and little parental care.

Examples of r-selected species?

Insects, weeds, microorganisms.

What are K-selected species?

Species with fewer offspring, slower growth, and high parental care.

Examples of K-selected species?

Humans, bears, elk, trees.

What is interspecific competition?

Competition between different species.

What is intraspecific competition?

Competition within the same species.

What is Gause's Principle?

Two species cannot occupy the same niche indefinitely; one will be excluded.

What is competitive exclusion?

One species eliminates another when they compete for the same niche.

What is a predator-prey relationship?

An interaction where predators consume prey and regulate population sizes.

What is coevolution?

Two species evolving in response to each other.

What is camouflage?

Adaptations that help organisms blend into their environment.

What is aposematic coloration?

Bright warning colors indicating danger or toxicity.

What is mimicry?

One species resembles another species for protection.

What is Batesian mimicry?

A harmless species mimics a harmful species.

What is Müllerian mimicry?

Two harmful species resemble one another.

What is parasitism?

One species benefits while the host is harmed (+/-).

What is mutualism?

Both species benefit (+/+).

What is commensalism?

One species benefits while the other is unaffected (+/0).

What is succession?

The gradual change in species composition over time.

What is primary succession?

Succession that begins where no community previously existed.

What is secondary succession?

Succession following a disturbance where soil remains.

What are pioneer species?

The first organisms to colonize an area.

Examples of pioneer species?

Lichens, grasses, weeds.

What are seral species?

Intermediate species in succession.

Examples of seral species?

Shrubs and softwood trees.

What is a climax community?

A stable, mature community at the end of succession.

Examples of climax species?

Hardwood trees.

What events increased human population growth?

Agricultural revolution, industrial revolution, and advances in medicine.

What is an age pyramid?

A graph showing the age structure of a population.

What can age pyramids predict?

Whether a population will grow, stabilize, or decline.

What is zero population growth?

A population with no net increase or decrease in size.

How do you calculate the frequency of a recessive allele when q² is known?

Take the square root of q².