edu290 part 1 evolution and biodiversity
TRANSCRIPT
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