BIOLOGY EOCT REVIEWDay 5: Evolution

CHARLES DARWIN

Traveled on the Beagle to the Galapagos Islands Studied 13 species of finches on the islands Hypothesized that all originated from 1

ancestor Explained his theory of NATURAL

SELECTION Published in On the Origin of Species Influenced by Lyell and Wallace Strayed from Lamarck’s “inherited traits”

theory

NATURAL SELECTION

Survival of the Fittest Fit = best adapted to environment for survival

Mice will display gray coloring rather than white

THEORIES OF EVOLUTION

Adaptations Changes in response

to the environment and becomes a new species

Required to survive in the changing world

Reproductive Isolation A species is

separated and becomes two separate species

EVOLUTIONARY TERMS

Speciation Creation of a new

species A species can mate

and produce viable offspring

Extinction A species ceases to

exist Can occur gradually

(rainforest plants) or as a mass extinction (dinosaurs)

Biodiversity Number of different

species/organisms

Biodiversity inside a classroom is much lower than the biodiversity outside

Inside: humans, insects

Outside: humans, insects, plants, animals, etc.

GENES

Gene Pool Genes available for

reproducing

Gene Flow Introducing genes

from one gene pool into another gene pool

SPECIATION

Gradualism Punctuated Equilibrium

FOSSILS AND PHYLOGENY

Radioisotope Dating Provides EXACT age

of fossils

Uses the half-lifes of radioactive isotopes (Carbon-14)

Relative Dating Provides

APPROXIMATE age of fossils

Generally, older fossils are found in rock layers beneath younger fossils

FOSSILS AND PHYLOGENY

Analogous Structures

Vestigial Structures Used by common ancestor but no longer

necessary

Homologous Structures

FITNESS AND SELECTION

Stabilizing Selection Selects for the central trait

Directional Selection Selects for one extreme trait

Disruptive Selection Selects for both extreme traits

PRINCIPLES OF NATURAL SELECTION

Variations exists within populations.

Organisms compete for limited natural resources.

Organisms produce more offspring than can survive.

Individuals with variations suitable for their habitat survive and reproduce.

BIOLOGICAL RESISTANCE

Natural selection allows for the resistant bacteria and pests to survive and reproduce offspring that are also resistant

Antibiotic resistance The overuse of antibiotics leads to “superbugs”

Pesticide resistance Farmers must increase the use of pesticides on

crops as pests become immune/resistant to doses