Evolution Notes Part 1: Natural Selection and Adaptation

What is evolution? the process in which inherited characteristics within a population change over generations such that new species arise.

History of evolution- Jean Baptiste de Lamarck proposed the first known theory of evolution. He believed that altered behavior leads to greater or lesser use of a given structure or organ; use would cause the structure to increase in size over several generations, whereas disuse would cause it to shrink or even disappear. This theory has since been disproved by modern genetics.

History of Evolution- Charles Darwin Charles Darwin set out his theory of evolution by natural selection. He defined natural selection as the "principle by which each slight variation, if useful, is preserved". Darwin defined evolution as "descent with modification," the idea that species change over time, give rise to new species, and share a common ancestor.

Natural Selection Natural selection is the way that evolution happens! The process in which organisms better adapted to their environment tend to survive and produce more offspring. https://www.brainpop.com/ science/cellularlifeandgenet ics/naturalselection/

Natural Selection The process of natural selection has four parts. Each part is simply a variable that CAN contribute to the “why” of the organism being successful in its environment.

Adaptation An adaptation is a structure, behavior or physiological process. These help an organism to survive and reproduce in particular environment.

Types of Adaptation Mimicry versus Camouflage Both mimicry and camouflage are forms of defense for a species. Camouflage is when a species can change their colors or patterns to match its environment to blend in, like a chameleon! And mimicry is when a harmless creature makes itself look dangerous. Camouflage Mimicry

Evolutionary Timelines Punctuated equilibrium: theory that species can remain unchanged for millions of years and then have a sudden, drastic change in response to sudden environmental changes. This can also lead to speciation. The idea of quick bursts of evolutionary change is supported by a lack of transitional fossils in the fossil record. Gradualism: theory that changes in species occur slowly and steadily over thousands of years.

Speciation the formation of new and distinct species in the course of evolution. https://www.youtube.com/watch?v=udZUaNKXbJA