Unit 7 exam EC- Helena Nunes

Natural Selection

Differential survival and reproduction due to phenotype.

Favorable Traits

Traits that are more likely to be passed on to the next generation.

Phenotypic Variation

The raw material for natural selection.

Artificial Selection

Human influence on traits, such as in selective breeding of dog breeds.

Evolution

The process through which species change over time.

Mutation

A change in the DNA sequence that can create new alleles.

Variation

Differences in traits among individuals in a population.

Fitness

The ability of an organism to survive and reproduce in its environment.

Adaptation

A characteristic that improves an organism's ability to survive and reproduce.

Directional Selection

A mode of natural selection in which a favored trait increases in frequency.

Disruptive Selection

A selection process that favors extreme values of traits over intermediate values.

Stabilizing Selection

A selection process that favors average traits and reduces variation.

Selective Pressure

External factors that affect an organism's ability to survive in a given environment.

Adaptive Radiation

The diversification of a group of organisms into forms filling different ecological niches.

Genetic Drift

Random changes in allele frequencies in a population, particularly in small populations.

Bottleneck Effect

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

Founder Effect

Reduced genetic diversity that occurs when a population is established by a very small number of individuals.

Gene Flow

The transfer of genetic variation from one population to another.

Allele Frequency

The relative frequency of an allele at a genetic locus in a population.

Hardy-Weinberg Equilibrium

The principle that allele and genotype frequencies in a population remain constant in the absence of evolutionary influences.

Sexual Selection

A mode of natural selection where certain traits increase mating success.

Immigration

The movement of individuals into a population from elsewhere.

Emigration

The movement of individuals out of a population.

Fossil

The preserved remains or impressions of ancient organisms.

Radiometric Dating

A method used to determine the age of an object by measuring the decay of radioactive isotopes.

Homologous Structures

An anatomical feature that is similar in different species due to common ancestry.

Analogous Structure

Body parts that share a common function but not structure, reflecting convergent evolution.

Vestigial Structures

Body parts that have lost their original function through evolution.

Comparative Embryology

The comparison of embryos from different species to find similarities reflecting common ancestry.

Biogeography

The study of the geographical distribution of species.

Transitional Fossil

Fossils that show intermediate states between an ancestral form and its descendants.

Half-Life

The time required for half of a sample of a radioactive substance to decay.

Index Fossil

A widely distributed fossil that is used to date the rock layers in which it is found.

Phylogeny

The evolutionary history and relationships among species.

Cladogram

A diagram that shows the evolutionary relationships among a group of organisms.

Node

A point in a phylogenetic tree where a branch splits, representing a common ancestor.

Sister Taxa

Groups of organisms that share an immediate common ancestor.

Outgroup

A lineage that is closely related to but not part of the group being studied.

Molecular Clock

A method of estimating the time of divergence between species based on molecular data.

Shared Character

A trait that two or more taxa have in common.

Derived Character

A trait that evolved within a particular lineage.

Species

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

Speciation

The process by which new species arise.

Prezygotic Isolation

Reproductive barriers preventing mating or fertilization between species.

Postzygotic Isolation

Reproductive barriers that occur after fertilization.

Allopatric Speciation

Speciation that occurs when populations are geographically isolated.

Sympatric Speciation

Speciation that occurs without geographic isolation, often due to behavioral or genetic barriers.

Gradualism

The theory that species evolve slowly but continuously over long periods.

Punctuated Equilibrium

The theory that species evolve during short bursts of rapid change.

Convergent Evolution

The independent evolution of similar traits in different lineages.

Divergent Evolution

The process whereby groups from the same common ancestor evolve and accumulate differences.

Mass Extinction

A significant and rapid decrease in biodiversity on Earth.

Biodiversity

The variety of life in the world or in a particular habitat or ecosystem.

Niche

The specific role or function of an organism within its ecosystem.

Speciation Rate

The speed at which new species are formed.

Extinction Rate

The speed at which species go extinct.

RNA World Hypothesis

The idea that self-replicating ribonucleic acid (RNA) was the precursor to current life.

Organic Molecules

Carbon-containing molecules essential for life, such as proteins, lipids, carbohydrates, and nucleic acids.

Amino Acids

The building blocks of proteins.

Nucleotides

The basic structural unit of nucleic acids like DNA and RNA.

Polymerization

The process of combining small molecules (monomers) to form larger molecules (polymers).

Free Energy

The energy in a system that can be used to do work.

Prebiotic Earth

The condition of Earth before the emergence of life.