CH4: Evolution History and Evidence

Organic Evolution

Proposed by Charles Darwin, it refers to "descent with modification" where plants and animals originate from earlier forms, leading to generational changes.

Pre-Darwinian Theories

The ideas about evolution that existed before Darwin's theory, including various perspectives from philosophers and scientists.

Empedocles

Proposed that the first creatures were disembodied organs and that all matter was composed of four elements:fire, air, water, and earth.

Aristotle

Believed species were fixed and unchanging, with a natural tendency to develop towards a final, perfect state known as telos.

Georges-Louis Buffon

Suggested that species undergo changes and that all animals might have evolved from a single breeding pair.

Erasmus Darwin

Argued that the strongest and most active animals should propagate the species, leading to improvement, coining the phrase “survival of the fittest.”

Jean Baptiste Lamarck

Proposed that evolutionary change occurs depending on the needs of the species.

Artificial Selection

The process where humans breed plants or animals for specific traits.

Natural Selection

The process through which populations of living organisms adapt and change over time.

Theory of Evolution by Natural Selection

States that organisms better adapted to their environment are more likely to survive and pass on advantageous genes.

High Reproductive Potential

A characteristic of organisms that can produce many offspring, contributing to natural selection.

Inherited Variations

Differences in traits that are passed down from parents to offspring, crucial for evolution.

Constant Struggle for Limited Resources

The competition among individuals for resources, leading to survival challenges.

Adaptive Traits

Traits that enhance an organism's chances of survival and reproduction, becoming more common in future generations.

Adaptation

A heritable change in phenotype that increases an animal's reproductive success, arising from chance mutations and perpetuated by natural selection.

Relative Dating Techniques

Methods for estimating time relationships between events based on their position in rock strata without assigning absolute dates.

Stratigraphy

A relative dating technique that correlates strata around the world based on their position.

Absolute Dating Techniques

Methods like radiometric and molecular dating that assign specific dates to rock strata and past events.

Mass Extinction

A significant event where a large number of species become extinct in a relatively short period.

Asteroid Impacts with Earth

A hypothesis for mass extinction that could create an "impact winter," leading to global cooling and death of photosynthetic organisms.

Volcanic Event

A hypothesis for mass extinction involving deadly emissions of sulfur and CO2 that could spread globally.

Microevolution

Changes in the frequency of alleles in a population over time.

Macroevolution

Large-scale evolutionary changes that result in the extinction and formation of new species.

Biogeography

The study of the geographic distribution of plants and animals, revealing distinctive evolutionary histories.

Paleontology

The study of the fossil record, providing evidence of the appearance and disappearance of organisms.

Fossils

Remains of plants and animals from the past that have become part of the earth's crust.

Homology

Resemblance due to common ancestry, indicating evolutionary relationships among different species.

Homology-Comparative Anatomy

The study of structures in living and fossilized animals that indicate evolutionary relationships.

Convergent Evolution

The evolution of similar structures in unrelated organisms due to similar environmental pressures.

Phylogenetic Trees

Diagrams that show lines of descent among species.

Branches

Represent evolutionary connections in phylogenetic trees.

Nodes

Branch points in phylogenetic trees where changes occur in genes, populations, or species.