Evolution of Biodiversity Evolution of Biodiversity The Dung

Evolution of Biodiversity

Evolution of Biodiversity The Dung of the Devil • 1918 -20 Spanish flu wiped out 20 -100 million people worldwide. • H 1 N 1 virus • The “Dung of the Devil” is a plant that fights the flu. • Many other examples of plants and animals that fight illnesses. • 70% of new drugs are first discovered in plants and animals

Species: a group of organisms distinct from others and can successfully breed.

Biodiversity on 3 Separate Scales Ecosystem Diversity: variety of ecosystems. Species Diversity: variety of species. Genetic Diversity: variety of genes. All three scales of biodiversity contribute to the overall biodiversity of the planet

How Many Species? ? • 2 million have been named. • Estimates average around 10 million.

Species Richness and Evenness Species Richness: The number of species in a given area. Species Evenness: Relative abundance of each species. Both together make up biodiversity! Declines after a human disturbance.

Determining Evolutionary Relationships Phylogenies: branching patterns of evolutionary relationships.

Evolution is the Mechanism Underlying Biodiversity Evolution: change in genes over time within a population. Microevolution: at the species level. Macroevolution: giving rise to new species.

Genes: sections of DNA that code for proteins. Genotype: genetic make up. Phenotype: physical characteristics.

Genetic Change Mutation: random change. Recombination: meiosis and random fertilization.

Evolution!! Can happen by. . 1. Artificial Selection 2. Natural Selection 3. Random Processes

Artificial Selection • Picking particular traits and breeding those individuals. • Agriculture and livestock. Unintended Consequences: • Resistant weeds. • Resistant antibiotics.

Evolution by Natural Selection • Environment determines what will survive.

Darwin: The Father of Evolution Darwin’s 5 Premises: 1. 2. 3. 4. 5. Individuals produce an excess of offspring. Not all offspring can survive. Individuals differ in their traits. Organisms give birth to like organisms. Differences in traits are associated with differences in the ability to survive.

Fitness: ability to survive and reproduce. Adaptations: traits that improve an individual’s fitness.

Evolution by Random Processes 1. Mutation

2. Genetic Drift: Change in the genetic composition of a population over time as a result of random mating.

3. Bottleneck Effect: drastic reduction in the size of a population resulting in a reduction of the genetic diversity.

4. Founder’s Effect: change in population from a small number of colonizing individuals.

Speciation and Extinction Determine Biodiversity Speciation: making a new species. Moving from microevolution to macroevolution.

Geographic Isolation: separate due to a geographical barrier. Allopatric Speciation: geographic isolation forces two species to adapt differently. Eventually they cannot breed.

Sympatric Speciation: evolution of one species into two species without geographic isolation. Polyploidy: more than two sets of chromosomes.

Pace of Evolution • 1 new species every 3 million years. Four Factors Influence Successful 1. 2. 3. 4. Rate of Environmental Change Genetic Variation Population Size Generation Time

Genetic Engineering: directly manipulating genes. Genetically Modified Organisms (GMOs): Organisms with inserted genes.

Evolution Shapes Ecological Niches and Determines Species Distributions Range Tolerance: limits to the abiotic conditions they can tolerate. Niche: the role an organism plays in the environment. Fundamental Niche: ideal conditions. Realized Niche: where the organism actually lives.

Environmental Change and Species Extinctions • 99% of all species that have ever lived on Earth are now extinct. Why? • No favorable habitat.

Fossil Record • Fossils: remains of organisms that have been preserved in rock. • Oldest are found on the bottom.

The Five Global Mass Extinctions • Revealed through the fossil record. • Greatest: 251 million years ago: 90% of marine organisms and 70% of land organisms died off. • Most recent: 65 million years ago at the end of the Cretaceous period. • ½ of the Earth’s species including dinosaurs went extinct. • Possibly a meteorite.

The Sixth Mass Extinction • • Currently within the 6 th mass extinction. 2 -25% of species could be lost by 2025. Due to human causes. Include but not limited to: habitat destruction, invasive species, overharvesting, climate change, and emerging diseases.