Evolution and Comparative Anatomy Flashcards

Flashcards about Evolution and Comparative Anatomy

Charles Darwin's Contribution

Observations about animals on the Galapagos Islands and the development of an evolutionary tree.

Fossilization

The process by which an organism becomes a fossil over time, usually in sedimentary rock.

Homologous Structures

Structures in different species that are similar because of common ancestry.

Analogous Structures

Structures in different species that perform the same function but have evolved separately, thus do not share common ancestry.

Vestigial Structures

Structures in an organism that have lost all or most of their original function in the course of evolution.

Natural Selection

Is survival of the fittest; reproductive success results from inherited traits or characteristics to adapt and survive.

Reproductive Isolation

Is when something prevents mating between different populations or species.

Temporal Isolation

Different species mate at different times of the year.

Ecological/Habitat Isolation

Species live in different habitats or continents.

Behavioral Isolation

Different mating calls occur.

Mechanical Isolation

Physical differences prevent mating.

Hybrid Infertility

Hybrid offspring is sterile.

Microevolution

Changes in allele frequency in a small period of time from one generation to the next.

Bottleneck Effect

A catastrophic event that greatly reduces the variety in a population, decreasing allele frequency.

Founder Effect

When a species moves to a new area and takes a portion of the gene pool.

Gene Flow

Entering alleles bring alleles, and leaving alleles take alleles.

Development of Resistance in Microorganisms

Roaches that didn't die in an extermination reproduce and create immune offspring.

Gradualism

Very small changes over a long period of time.

Punctuated Equilibrium

Sudden drastic change and then no change for a long time.

Population

Members of the same species that live in the same area, can interbreed, mate, and create viable offspring.

Stabilizing Selection

Selection that favors intermediate variants by acting against extreme phenotypes.

Directional Selection

Selection that favors one extreme phenotype over the others, causing the allele frequency to shift over time in the direction of that phenotype.

Disruptive Selection

Selection that favors both extreme phenotypes over intermediate phenotypes, leading to a divergence in allele frequencies.

Conditions for Hardy-Weinberg Equilibrium

No mutations, random mating, no natural selection, and no gene flow.