Evolution

Descent with Modification

Living organisms share a common ancestry and evolve through modification over long periods.

Natural Selection

Evolutionary mechanism where individuals with advantageous traits are more likely to survive and reproduce.

Common Ancestry

All organisms are connected through a tree of life, sharing common ancestors.

Gradualism

Evolution occurs slowly, with small changes accumulating over time.

Fossil Evidence

Transitional forms in fossils show gradual species changes.

Biogeography

Species distribution explained by evolutionary history and continental movement.

Homology

Similarities in anatomy and genetics indicate common ancestry.

Variation

Differences in traits among individuals within a population.

Genetic Variation

Differences in inherited traits and alleles.

Phenotypic Variation

Observable differences in physical characteristics influenced by genetics and environment.

Morphological Variation

Differences in physical structure within a population.

Behavioral Variation

Differences in behaviors within a species.

Geographic Variation

Trait differences in different geographic regions.

Temporal Variation

Changes in traits over time.

Cultural Variation

Differences in behaviors within human populations.

Intraspecific Variation

Variation within a single species.

Interspecific Variation

Differences between different species.

Fossil Record

Collection of fossils showing the history of life on Earth.

Homologous Body Structures

Similar structures in different organisms indicating common ancestry.

Vestigial Organs

Body parts that have lost their original function through evolution.

Embryology

Study of embryo development showing common patterns in different species.

Biochemical Evidence

Comparisons of genetic material supporting evolutionary relationships.

Charles Darwin

Proposed evolution by natural selection in "On the Origin of Species" in 1859.

Evolution by Natural Selection

Darwin's theory of species evolving through advantageous traits.