EcoEvo Unit 1: History of Evolutionary Thought

evolution

change in allele frequency in a population across generations

homologous structures

presence of structures in organisms that share the same basic form

vestigial structures

structures that exist in organisms that have no apparent function at all, and appear to be residual parts from a past common ancestor

Plato and Aristotle

Believed that species are static and unchanging, and represent perfect “types” that are independent and form a hierarchy

Georges Louis Leclerc de Buffon

Observed that various geographic regions have different plant and animal populations, even when the environments are similar

James Hutton and Charles Lyell

Proposed that geological change occurred gradually over long periods of time from processes like erosion and uplift

Jean-Baptiste de Lamarck

Proposed a mechanism for evolutionary change: inheritance of acquired characteristics \`

Charles Darwin

Proposed natural selection as a mechanism for evolutionary change

Zhuang Zhou

Ancient Chinese scholar that wrote about the struggle for survival among individuals and how organisms change over time

Nicholas Steno

The first to recognize fossils were remains of organisms.

Baron Georges Cuvier

First to recognize the concept of extinction; observed that fossils resemble but are not exactly the same as modern species

Thomas Malthus

Socio-economist; wrote relationship between population size and resources

Alfred Russel Wallace

Proposed natural selection as a mechanism of evolutionary change

Al-Jahiz

Ancient Islamic scholar that wrote about the struggle for survival among individuals and how organisms change over time

Malthusian catastrophe

Occurs when population size exceeds resource availability, leading to intense competition and crash of population size

fossil

Preserved remains or traces of organisms from prehistoric time

permineralization

process of fossilization in which minerals enter dead organic material and form internal cast

transitional feature

trait in a fossil that is intermediate between ancestral (older) and derived (newer) species

adaptation

a heritable trait that helps an organism’s survival and reproduction in its present environment

variation

genetic differences among individuals in a population

Steno’s Law of Superposition

time sequence of rock layers; as you go deeper into the ground, the older the layers and fossils are

body fossil

Bones, skin, eggs, etc… must be part of an organism

trace fossil

footprint

Evidence of evolution at different levels

Morphology: ex) bones in forelimbs of vertebrates

Embryology: ex) tail in developing embryos of vertebrates

Molecular: ex) similarity in genes of fruit flies and mammals

Law of succession

extinct species were succeeded by similar species

Tiktaalik

fossil that shows the transition between a fish and a tetrapod (four-legged animal); shows transitional features