Exam 2 Evolutnionary Biology

What is sexual reproduction?

Sexual reproduction is a method of reproduction that involves the combination of genetic material from two individuals, typically resulting in greater genetic diversity.

What is the biggest cost of sexual reproduction?

Asexual females are twice as genetically related to their offspring as are sexual females.

What is the twofold cost of sex?

A male’s only function is to inseminate females, while males never reproduce offspring directly.

What is one way sex can disrupt evolutionary advantages?

Sex can break up favorable gene combinations, creating genetic variation that might not always be beneficial.

List one cost of searching for a mate.

Searching for potential mates requires significant time and energy.

How does courting potential mates add cost?

It takes time and energy for individuals to court potential mates, which can be resource-intensive.

What is a potential cost of focusing on courting mates in the wild?

Individuals may become less vigilant for predators when searching for and courting potential mates.

What is one benefit of sexual reproduction?

Sexual reproduction can purge deleterious mutations, helping to maintain the health of populations.

Explain Muller’s Ratchet in relation to sexual reproduction.

In sexual reproduction, deleterious mutations can be purged over generations, while asexual reproduction can accumulate these mutations.

What does the Fisher-Muller Hypothesis suggest?

Sex accelerates adaptive evolution by allowing beneficial mutations from different individuals to recombine.

What is the Red Queen hypothesis?

Sexual reproduction helps hosts adapt to rapidly evolving pathogens, likened to a genetic arms race.

Define sexual selection.

Sexual selection is a process that depends on the advantage certain individuals have over others of the same sex regarding reproduction.

What are the two types of sexual selection?

Intersexual selection (one sex chooses mates of the other sex) and Intrasexual selection (members of one sex compete for access to mates).

Give an example of intrasexual selection.

Male elephant seals engage in physical battles to gain access to females.

What does the Hamilton-Zuk hypothesis propose about mate choice?

Healthy males can be identified by their coloration, as unhealthy males tend to be drab, which helps females choose mates resistant to parasites.

What is runaway sexual selection?

The process where a trait in males becomes genetically associated with a female's preference for that trait, potentially leading to exaggerated traits.

What is the sensory bias hypothesis?

This hypothesis suggests that females may prefer certain male traits because they are tied to benefits outside of mate choice.

Provide an example of intrasexual selection in grasshoppers.

Large male grasshoppers can be more competitive because they can pull other males away from potential mates.

What can sexual conflict result in?

Sexual conflict can lead to traits in one sex that unintentionally harm the other, such as male honeybee sperm causing temporary blindness in queens.

Horizontal gene transfer (HGT)

The process by which genetic material is exchanged between different organisms, potentially leading to more complex cellular organisms.

LUCA (Last Universal Common Ancestor)

The hypothetical last common ancestor of all current life on Earth, believed to be a pool of early life forms exchanging gene components.

Self-replicating molecules

Molecules capable of making copies of themselves, believed to be crucial in the origin of life.

Endosymbiotic theory

The theory that mitochondria and chloroplasts originated as separate prokaryotic organisms that were engulfed by ancestral eukaryotic cells.

Multicellularity

The condition of an organism consisting of many cells, which allows for complex structures and functions.

Germ cells

Reproductive cells that can give rise to gametes and carry genetic information to the next generation.

Somatic cells

Non-reproductive cells that form the tissues and organs of an organism.

Many eyes hypothesis

The idea that larger groups have more individuals acting as lookouts, increasing the chances of detecting predators.

Eusociality

A high level of social organization in some animal species, characterized by cooperative brood care, overlapping generations, and a division of labor.

The evolution of complexity

The process by which simpler forms of life develop into more intricate and specialized forms over time.

Volvocine algae

A group of green algae that exhibit a range of organizational complexity from unicellular to multicellular forms with specialized cell differentiation.

Last Universal Common Ancestor (LUCA)

Not a single organism, but a population that left descendants still present today.

Prebiotic Soup Hypothesis

The idea that early Earth's atmosphere lacked oxygen and contained a pool of molecules that eventually led to life.

Spiegelman’s Monster

An experiment where RNA molecules replicate and evolve in a test tube environment, demonstrating natural selection.

Miller and Urey Experiment

Simulated early Earth conditions to produce amino acids from methane, hydrogen, ammonia, and water.

RNA World Hypothesis

Theory suggesting that early life forms were based on RNA rather than DNA.

Homeostasis

The ability of an organism to maintain a stable internal environment.

Molecular Mutualism

A relationship where multiple molecular substrates improve each other's replication.

Ribozymes

RNA molecules that can act as enzymes, facilitating chemical reactions.

Chemical Stability of DNA

DNA is more stable than RNA, allowing for lower mutation rates and longer genes.

Phylogenetic Event Horizon

The point in history of life beyond which phylogenetic analysis cannot infer information.

Species

A group of organisms that can interbreed and produce fertile offspring.

Speciation

The process by which new species arise.

Culex pipens

A species of mosquito that thrives both above and below ground.

Evolutionary Species Concept

Defines a species as a lineage of populations which maintains its identity from other lineages.

Phenetic Species Concept

Groups individuals and populations based on clusters of phenotypic similarities.

Biological Species Concept

Defines a species as groups of interbreeding populations that are reproductively isolated from others.

Phylogenetic Species Concept

Defines a species based on unique shared derived characters within monophyletic groups.

Allopatric Speciation

Speciation that occurs when populations are geographically isolated.

Parapatric Speciation

Speciation that occurs in adjacent populations without a geographic barrier.

Sympatric Speciation

Speciation that occurs without geographic isolation.

Introgression

The incorporation of genes from one species into the gene pool of another through hybridization.

Hybrid Zone

An area where diverging populations meet and mate, producing hybrid offspring.

Ring Species Concept

A connected series of populations that can interbreed, but where the ends of the spectrum cannot.

Reproductive Isolation

A set of mechanisms that prevent different species from interbreeding.

Gene Flow

The transfer of genetic variation from one population to another.

Fossils

Preserved remains of organisms from the past, often used to study evolution.

Asexual Reproduction

A mode of reproduction where an organism can reproduce without the involvement of another organism.

Hybridization

The process of mating two different species or varieties.

Biogeography

The study of the geographic distribution of life and the factors that influence this distribution.

Natural selection

The process where organisms better adapted to their environment tend to survive and produce more offspring.

Genetic drift

Random changes in allele frequencies in a population, which can lead to significant evolutionary changes over time.

Bottleneck populations

A sharp reduction in the size of a population due to environmental events or human activities that reduces genetic diversity.

Founder effect

The reduced genetic diversity that results when a small number of individuals from a larger population establish a new population.

Panbiogeography

An approach to biogeography that involves mapping specific taxa to study their geographical movement.

Phylogeography

The study of the historical processes that influence the geographic distributions of genealogical lineages.

Wallace Line

A faunal boundary line that separates the ecosystems of Asia and Australia, drawn by naturalist Alfred Russel Wallace.

Convergent evolution

The process where similar traits evolve independently in different species due to adaptation to similar environments.

Divergent evolution

The process in which two or more related species become more dissimilar over time, often due to different environmental pressures.

Geological barriers

Physical barriers such as mountains and bodies of water that can limit the movement and distribution of species.

Leading edge subpopulations

Populations near the limit of a species' range that help colonize new, habitable areas after environmental changes.

Mitochondrial DNA

DNA located in the mitochondria, passed down through maternal lines, which can be used to study population genetics and movement.

Genetic diversity

A measure of the variety of different versions of genes within a given species.

Climate influence on evolution

Changes in climate can impact natural selection, migration patterns, and the overall distribution of species.

Behavioral dispersion

Variability in organism behaviors that can affect their ability to spread and adapt to new environments.

Genetic Drift

A mechanism of evolution causing random changes in allele frequencies within a population.

Divergence

The process by which two or more related populations become more dissimilar over time.

Population Bottleneck

A sharp reduction in the size of a population due to environmental events or human activities.

Founder Effect

A change in allele frequencies that occurs when a small number of individuals colonize a new area.

Heterozygosity

The presence of different alleles at one or more loci on homologous chromosomes.

Microsatellites

Short, repeating sequences of DNA that tend to mutate frequently and are used in genetic studies.

Allele Frequency

The relative frequency of an allele at a genetic locus in a population, expressed as a proportion.

Southern Elephant Seal

A seal species that has not faced significant hunting pressure, leading to higher genetic diversity.

Northern Elephant Seal

A seal species that was heavily hunted to near extinction, resulting in lower genetic diversity.

Natural Selection

The process where organisms better adapted to their environment tend to survive and produce more offspring.

Demography

The statistical study of populations, including the structure, distribution, and trends in population dynamics.

Migration

The movement of individuals from one population to another, which can affect genetic variation.

Galápagos Lava Lizards

A species exhibiting divergence influenced by genetic drift and environmental factors.

Evolutionary Drivers

Factors that contribute to evolutionary changes within species populations, such as nonrandom mating and migration.

Random Mating

A type of mating in which all individuals have an equal opportunity to mate with any other individual.

Sea Level Rise

The increase in the global average height of the ocean's surface, impacting coastal ecosystems.

Old Order Amish

A group characterized by genetic drift due to a limited founding population, leading to specific hereditary conditions.