What is Evolution?

85 million people x .08 ha/person= 7 million ha Let’s Do Some Math If 85 million Americans have an averaged sized lawn that is .08 ha, how much total land area is composed of lawns in the U.S.? 85 million people x .08 ha/person= 7 million ha 2.2 billion liters (.6 billion gallons) of gasoline are used annually for lawn mowers. If gas costs $.80/L ($3.00/gal), how much money could be saved annually if each lawn owner stopped mowing 10% of their lawn? 2,200,000,000 liters x $0.80/liter x .1 (10%) = $176, 000, 000 or ~$180 million

Evolution of Biodiversity Dung of the Devil- plant extracts combat H1N1 Flu virus Chapter 5 Evolution of Biodiversity

Earth is home to a tremendous diversity of species ~ 2 million species that have been officially named. Unidentified species (5 mil to 100mil???)

Cladograms/Phylogenetic Trees Show evolutionary relationships- common ancestry

Measure of Biodiversity Species richness (N) - the number of species in a given area. Species evenness (n)- distribution of species – Is ecosystem dominated by 1 species or equal distribution of species. Species richness is the same for both; Com 1 has greater species evenness= more diverse

Evolution is the mechanism underlying biodiversity Evolution- Changes in ALELLE FREQUENCY (genetic characteristics) over time. Populations gradually evolve over time. Microevolution- small changes; Ex: insects resistant to pesticides. Macroevolution- New species created LARGER SCALE

Charles Darwin’s TWO Main Conclusions 1. Species evolved from their ancestoral forms. DESCENT WITH MODIFICATION. 2. Natural Selection (SURVIVAL of the Fittest/SEXIEST) is the mechanism for evolution.

Evolution By Natural Selection FIT= survive and reproduce NOT strong 1.Individuals with favorable traits have an advantage over others. 2.When environmental conditions change POPULATIONS: * Adapt (traits coded for by genes that improve an organism’s fitness.) * Migrate * Become extinct

Evolution By MUTATION Mutations- Random or environmental factors (excess UV, chemicals) NOT ALL MUTATIONS ARE BAD!!!!!!!!! Antibiotic resistance in bacteria Sickle cell resistance to Malaria

EVOLUTION BY ARTIFICIAL SELECTION when humans SELECT which individuals breed.

Evolution by Random Processes- NOT BASED ON FITNESS 1. Genetic drift- change in the genetic composition of a population over time as a result of random mating. “BY CHANCE”

Evolution by Random Processes 2. Bottleneck effect- loss of genetic diversity. population size due to natural disaster, disease, overhunting, etc.

Evolution by Random Processes 3. Founder effect- new colony is started by a few members of the original population. Reduced genetic variation.

Founders, Bottleneck, and Genetic Drift https://www.youtube.com/watch?v=Q6J EA2olNts

Speciation When two species arise from one species. Causes: 1. Geographic isolation- physical isolation for long periods. 2. Reproductive isolation- mutation or behavioral changes make separated populations unable to breed with each other.

Speciation and extinction determine biodiversity Allopatric speciation- when new species are created by geographic or reproductive isolation.

Sympatric speciation- through the process of polyploidy (doubling of chromosome #. Common in flowering plants that are dioecious.

Factors that determine the pace of evolution 1.GRADUAL ENVIRON. CHANGE 2. HIGH GENETIC VARIATION 3. SMALL POPULATION 4. SHORT GENERATION TIME

Fundamental niche- the IDEAL conditions for a species. vs Realized Niche- Actual conditions (abiotic & biotic) that a species lives in

Niches Niche generalist- species that live under a wide range of conditions. Niche specialist- species that live only in specific habitats.

The Sixth Mass Extinction Scientists feel that we are in our sixth mass extinction, occurring in the last two decades- ANTHROPOGENIC CAUSE Estimates of extinction rates vary widely, from 2 % to 25% by 2020.