Evolution: Evidence, Theories, and Mechanisms in Biology

Evolution

A theory that fits evidence.

Age of Earth

4.5 billion years.

Radiometric dating

Calculates an age in years for geologic materials by measuring the presence of a short-life radioactive element.

Geologic column

Layers of the earth that give an idea of how long a layer has been living for.

Biogenesis

Origins of life.

Redi/Spallanzani

Conducted experiments to test the idea that life spontaneously existed.

Miller-Urey experiment

An experiment that caused random molecules to form into amino acids using original elements and a power source.

Fossils

Not easy to make; one in a billion.

Direct evidence

A piece of something from the past like a bone that's been petrified.

Indirect evidence

The idea of footprints or when the fossil gets molded into mud.

Lamarck's idea

Species change over time based on fossil evidence.

Acquired traits

The idea that traits could be acquired and passed on, which was incorrect.

Darwin's theory

Evolution is caused by natural selection; animals share a common ancestor.

Descent with modification

Descendants have a slightly different look than their parents.

Overproduction

Most creatures make more babies than they need.

Genetic variation

More kids lead to more genetic variety.

Struggle to survive

Genetic adaptation leads to survival of the fittest.

Differential reproduction

Reproduction selectivity where those who survive reproduce.

Natural selection pillars

Genetic variation, struggle to survive, differential reproduction, overproduction.

Homologous structure

Structures that are the same in different creatures, indicating a common ancestor.

Analogous structure

Structures that serve a similar function but do not share a common evolutionary origin.

Vestigial structure

Biological feature that has lost its original function during evolution.

Embryology

Development of an embryo from a fertilized egg into a fetus.

Biogeography evidence

Evolution occurs in populations due to geographical separation.

Gene pool

The total genetic diversity found within a population.

Sources of variation

Mutation, independent assortment, non-random mating, crossing over.

Reproductive isolation

Prevents different species from mating due to various isolating mechanisms.

Convergent evolution

Different species evolve similar traits due to similar environmental pressures.

Divergent evolution

Species evolve different traits due to reproductive isolation.

Coevolution

When two species evolve together for mutual benefit.

Gradualism

Evolution occurs through small, gradual changes over time.

Punctuated equilibrium

Long periods of stability interrupted by sudden changes.

Catastrophism

Natural disasters can cause rapid changes in ecosystems and evolution.

Phylogeny

The study of branching evolutionary histories.

Linnaean taxonomy

System of categorizing organisms based on shared traits.