Chapter 18–19 Evolution, Microevolution, and Macroevolution.

What is the "fixity of species" belief?

Species were individually created by God and do not change.

What did Plato believe about the world?

A real, perfect world and an illusory, imperfect world.

What was Aristotle's "Scale of Nature"?

Life forms are arranged on a ladder, each occupying a specific rung.

What is Linnaeus known for?

What is Linnaeus known for?

What is catastrophism, proposed by Cuvier?

Local catastrophes wipe out life; new species repopulate areas.

What is uniformitarianism by Hutton and Lyell?

Earth changes slowly and continuously by the same processes as today.

What is Malthus’ Principle of Population?

Population size is limited by available resources.

What did Lamarck propose about evolution?

Inheritance of acquired characteristics.

What is Darwin’s definition of evolution?

Accumulation of inherited differences over time.

What did Darwin observe on the Galápagos Islands?

Related species adapted traits to different environments.

What mechanism did Darwin and Wallace propose?

Natural selection.

What are the components of natural selection?

Inheritable variation, overpopulation, adaptive advantage.

What does "survival of the fittest" mean?

Individuals with favorable traits survive and reproduce.

What is artificial selection?

Humans breed organisms for desirable traits.

What is fossil evidence of evolution?

Fossils show succession and transitional forms between groups.

What is biogeography?

Study of organism distribution; supports common descent.

What are homologous structures?

Similar structures from a common ancestor.

What are analogous structures?

Structures with similar function but different ancestry.

What are vestigial structures?

Reduced or nonfunctional structures inherited from ancestors.

What embryological features show common ancestry?

Postanal tail, pharyngeal pouches, notochord, dorsal neural tube.

What is molecular evidence for evolution?

Shared DNA, codons, and proteins among living organisms

True or False: Evolution explains the origin of life.

False

What is microevolution?

Change in allele frequencies within a population over time.

What is a gene pool?

All alleles in a population.

What is Hardy-Weinberg Equilibrium (HWE)?

Allele and genotype frequencies remain constant without evolution.

What are the 5 conditions to maintain HWE?

No mutation, random mating, no gene flow, no genetic drift, no natural selection

What causes violation of HWE and leads to evolution?

Mutation, nonrandom mating, gene flow, genetic drift, natural selection.

What is genetic drift?

Random change in allele frequencies, especially in small populations.

What are the two types of genetic drift?

Bottleneck effect and founder effect.

What are the three patterns of natural selection?

Stabilizing, directional, and disruptive selection.

What is stabilizing selection?

Intermediate phenotype is favored over extremes, leading to reduced variation in a population.

What is directional selection?

One extreme phenotype is favored.

What is disruptive selection?

Two or more extreme phenotypes are favored over intermediate forms.

What is macroevolution?

Large-scale evolution forming new species.

What is speciation?

Formation of new species from an existing one.

What is the morphological species concept?

Based on physical traits.

What is the evolutionary species concept?

Species share an evolutionary pathway.

What is the phylogenetic species concept?

Defined by ancestry between two speciation events.

What is the biological species concept?

Based on reproductive isolation.

What is prezygotic isolation?

Prevents fertilization (habitat, temporal, behavioral, mechanical, gamete isolation).

What is postzygotic isolation?

Zygote mortality, hybrid sterility, reduced hybrid fertility.

What is allopatric speciation?

Speciation due to geographic separation.

What is sympatric speciation

Speciation without geographic separation.