Evolution - ACT Biology

Evolution

Change in inherited traits of a population over generations, leading to new species and diversity.

Population

Group of organisms of the same species living in the same area and capable of interbreeding.

Gene Pool

Total collection of genes and alleles in a population, subject to change over time.

Microevolution

Small changes in gene pool affecting a few genes over a short period.

Macroevolution

Formation of new species through speciation.

Mutations

Changes in genetic material, providing raw material for evolutionary change.

Gene Flow

Movement of alleles in/out of a population due to migration.

Genetic Drift

Random change in allele frequency over time, leading to loss of genetic variation.

Bottleneck Effect

Severe reduction in population size, resulting in loss of genetic diversity.

Founder Effect

Small population colonizes new area, leading to differences in allele frequencies.

Reproductive Isolation

Inability of individuals from same/species to interbreed, leading to speciation.

Prezygotic Barriers

Prevent mating or fertilization before zygote formation.

Postzygotic Barriers

Occur after mating, result in non-viable or infertile offspring.

Biogeography

Study of where organisms live now and where ancestors lived.

Continental Drift

Theory of continents moving over time, influencing biogeography.

Fossil Record

Reveals extinct and evolving species, provides evidence of evolution.

Prokaryotic Cells

Oldest fossils, first organisms to develop on Earth.

Homologous Structures

Similar in structure but different in function; evidence of common ancestry and divergent evolution.

Analogous Structures

Different in structure but similar in function; evidence of convergent evolution.

Vestigial Structures

Non-functional remnants from ancestors, such as the human appendix or snake limbs.

Comparative Biochemistry

Study of common biochemical pathways among different organisms.

Comparative Embryology

Study of similarities in embryonic development among different species.

Molecular Biology

Comparing amino acid sequences among organisms to determine relatedness.

Divergent Evolution

Population isolation leads to new species; examples include homologous structures.

Convergent Evolution

Unrelated species adapt similarly; examples include analogous structures.

Parallel Evolution

Related species adapt similarly after divergence.

Coevolution

Mutual evolutionary adaptations between closely associated species; examples include pollinator-plant relationships and predator-prey dynamics.

Adaptive Radiation

Numerous species emerge from a common ancestor; examples include Darwin's Finches.

Lamarck's Theory (Use and Disuse)

Traits change based on individual usage; experiment by Weisman disproved this theory.

Hardy-Weinberg Principle

Describes allele frequency constancy in stable populations.

Characteristics of a Stable Population

Large size, isolation, random mating, absence of selection, no mutations.

Darwin's Theory (Natural Selection)

Traits aiding survival and reproduction become more common; survival of the fittest.

Directional Selection

Extreme traits favored.

Stabilizing Selection

Intermediate traits favored.

Disruptive Selection

Extremes favored, intermediates disadvantaged.

Phyletic Gradualism

Evolution occurs gradually over long periods from a common ancestor; disproved.

Punctuated Equilibrium

Long periods of stability with short bursts of rapid change; accepted.

Spontaneous Generation

Living organisms emerge from non-living matter; disproved by Redi and Pasteur.

Francesco Redi's Experiment (1668)

Disproved spontaneous generation of maggots on decaying meat using covered and uncovered jars.

Louis Pasteur's Experiment (1864)

Sterilized broth in swan-necked flask to disprove spontaneous generation of microorganisms.

Origins of Life

Likely began in ancient environment with lack of oxygen but abundant methane, ammonia, and water vapor.

Miller-Urey Experiment

Showed organic molecules for life could form from inorganic components under early Earth conditions.

Theory of Endosymbiosis

Some organelles in eukaryotic cells were once prokaryotic microbes; supported by DNA and ribosomes.

Cladogram

Shows relationships based on common ancestor without evolutionary time.

Phylogenetic Tree

Depicts relationships based on characteristics, genetic background, and evolutionary time.