Evolution and Bio-Diversity

•Survival and Extinction

• Theory of Evolution

•Natural Selection

Survival and Extinction

Extinct Species•Baji Dolphin

Endangered Species•Siberian Tiger•West African Black Rhino

Species – A group of living organisms consisting of smaller individuals capable of interbreeding and exchanging genes.

MDPettitt, Siberian Tiger, July 17, 2008, Creative Commons License

Survival and Extinction

Population – A group of organisms of one species that interbreed and live in the same place at the same time.

Example:

Deer PopulationLoneTown, Deer ‘White Tail Deer’, February 20, 2011, Creative Commons License

Survival and Extinction

Removal of genes from gene pool

Survival and Extinction

Fossil Records

Majority of species are extinct

Give us insight to Earth’s history

Survival and Extinction

Fossil Records Continued

Displays how species have evolved

IvanWalsh, Fossils and Dinosaurs from Beijing Museum, December 5, 2009, Creative Commons License

EvolutionEvolution DefinitionAny change across successive

generations in the heritable characteristics of biological populations

EvolutionCharles Darwin

Created his own theory of evolution

All species from common ancestry

Branching pattern of evolution - natural selection

EvolutionDarwin’s Theory of Natural

Selection

Differential Survival

Essential to Darwin’s theory

Limited quantities of space and resources

Those most fit will survive

EvolutionBest displayed through

comparisons of:

Fossils

Modern species

Changes are displayed in different ways

EvolutionNatural Selection

Provides a mechanism for evolution

Process to explain evolution

Natural SelectionThe gradual non-random process through which biological traits become more or less common in a population

Natural SelectionHow it works

Traits are passed down generations

Beneficial traits are passed on

Negative traits disappear

Important traits are traits that:

Benefit reproduction and/or survival

Natural SelectionMutations

Some diversity comes from mutations

Beneficial mutations are passed on

Mutations can become part of genes

Example: Giraffes’

long necks

JRobertMoore, Giraffe, January 13, 2007, Creative Commons License

Natural SelectionGeographic Isolation

A species is physically separated

Plays important role in evolution

Two diverse groups form

Natural SelectionEnvironmental Factors

New predators or prey

Low food supply

Finite resources