Evolution and Phylogenetics Flashcards

Flashcards reviewing key vocabulary and concepts from the lecture notes on evolution, speciation, and phylogenetics.

Natural Selection

The survival of the fittest by having the ability of organisms to reproduce, leading to adaptations.

Darwin's Hypothesis

Food availability would make animals reproduce more.

Creationism

The belief that there are diverse but static and unchanging animals.

James Hutton and Charles Lyell

Geologists who noticed changes in Earth's surface from slow, continuous actions.

Thomas Malthus

Economist who stated limited resources encourages reproduction by competition.

Jean Baptiste de Lamarck

Proposed 'Use it or lose it' - species evolve through use and disuse of body parts.

Phylogenic Trees

Used to see the relationship of all organisms related by a common ancestor.

Divergent Evolution

When 2 species might look very different but share a common ancestor.

Convergent Evolution

Similar traits (adaptations) but do not share a common ancestor.

Half-life of C14

5730 years

Biological Species Concept

Organisms that successfully interbreed and have viable (fertile) offspring are in the same species.

Allopatric Speciation

Speciation created by a physical barrier that prevents two populations from interbreeding.

Sympatric Speciation

New species develop in the same geographic area. Same niche group or choice to mate.

Adaptive Radiation

When many species are derived from a single species, often after mass extinctions.

Prezygotic Barriers

Barriers that block fertilization.

Habitat Isolation

Two species encounter each other rarely because they occupy different habitats.

Temporal Isolation

Species that breed at different times cannot mix their gametes.

Behavioral isolation

Rituals or behaviors unique to a species

Mechanical isolation

Morphological differences

Gametic isolation

Sperm of one specious may not be able to fertilize

Postzygotic Barriers

Barriers that prevent the hybrid zygote from developing into a viable, fertile adult.

Hybrid Zones

A region in which members of different species mate and produce hybrids due to incomplete reproductive barriers.

Punctuated Equilibrium Model

Stasis followed by rapid change, contrasting with gradual speciation.

Allele

Version of a gene.

Gene Pool

Total alleles in population.

Inbreeding Depression

Result of shallow gene pool in a population lacking variation.

Genetic Drift

Die due to unexpected, Wrong place, wrong time!

Directional Selection

Favors individuals at one extreme end of the phenotypic range.

Diversifying Selection

Favors individuals at both extremes of the phenotypic range.

Stabilizing Selection

Favors intermediate variants and acts against extreme phenotypes.

Sexual Dimorphism

Marked differences between the sexes in secondary sexual characteristcs.

Intrasexual Selection

Direct competition among individuals of one sex for mates of the opposite sex.

Intersexual Selection

Individuals of one sex are choosy in selecting their mates.

Frequency-dependent Selection

Favors phenotypes that are either common (positive) or rare (negative).

Clines

How a species populations vary gradually across an ecological gradient.

Bottleneck Effect

A sudden reduction in population size due to a change in the environment.

Founder Effect

Occurs when a few individuals become isolated from a larger population, creating a new population and loosing diversity.

Gene Flow

Migration of Alleles in and out of a population , movement in and out with the diversity of population.

Chemical Evolution Theory

Describes the abiotic synthesis of organic molecules that ultimately resulted in the synthesis of the first living organism.

RNA World

The first genetic material was probably RNA, not DNA.

Stromatolites

The oldest known fossils, rocks formed by the accumulation of sedimentary layers on bacterial mats.

Endosymbiont Theory

Proposes that mitochondria and plastids were formerly small prokaryotes living within larger host cells.

Taxonomy

The science of classifying organisms.

Phylogeny

The evolutionary history and relationship of an organism or group of organisms.

Phylogenetic Tree

A diagram used to reflect evolutionary relationships among organisms.

Mass Extinction

Can alter ecological communities and the niches available to organisms, lineages with novel and advantageous features can be lost.