Causes of Diversity and Evolution of Life on Earth Charles Darwin Alfred Russell Wallace

Causes for Diversity of Life 1.All populations have the potential to increase in size 2.Many populations retain a constant size Many individuals die young 3. Individuals in a population differ in their abilities Some of these abilities affect survival 4.Best adapted individuals are most likely to survive and produce offspring (Natural Selection) “Abilities” are passed on to offspring (Genetics) 5.Over time the “abilities” of the population shift to include advantageous traits (Evolution)

Note: Natural Selection Affects Individuals Evolution Affects Populations

Net Result: Populations change with time to become better adapted to their environment (Evolution)

Example: Microbe Resistance Apply Antibiotic Survivor’s with Resistance Reproduce

How does it Work? Variation in the Gene Pool of a Population

How does it Work? Variation is a result of (1) Mutations and (2) Sex Errors occur in DNA Replication On average 1:10, ,000 genes per individual per generation Increased by exposure to radiation, etc. Most Mutations are bad or at least neutral What is “good” depends on environmental conditions

Evidence for Evolution

Evidence for Evolution: Fossils & Faunal Succession

Evidence for Evolution: Analogous Structures

Evidence for Evolution: Homologous Structures

Evidence for Evolution: Embryology

Evidence for Evolution: Biochemistry of Life

Evidence for Evolution: Gene Sequencing

Evidence for Evolution: Artificial Selection

Evidence for Evolution: Modern Examples

Some Interesting Effects of Evolution

Evolution & Psuedoextinction Species A Species B Through time Species A evolves into Species B In effect, Species A goes extinct

Extinction Species A Sometimes a species cannot adapt fast enough to environmental change or competition

Moa No moa, no moa, In old Ao-tea-roa. Can’t get ‘em. They’ve et ‘em. They’ve gone and there ain’t no moa!

Extinctions through time

Evolution & Speciation Species A Species B Species C Species A is separated into 2 isolated populations, each affected by different environmental conditions In effect, Species A goes Extinct

Speciation of Hawaiian Honeycreepers

Diversity Increases

Convergent Evolution

Coevolution: Plants and Pollinators

Coevolution: Predator/Prey

Relationships Between Living Things - Phylogony

Phylogony is Related to Classification Species Genus Family

Phylogony = Evolutionary History

Pseudo and True Extinction

Cladistics = Tool for Understanding Phylogony Based on Derived Traits NOT the present

SharkTuna Frog Dimetrodon Human Whale Crocodile Saurischian Bird Ornithoschian Time Phylogentic Tree

SharkTuna Frog Dimetrodon HumanWhaleCrocodileSaurischianBird Ornithoschian Cladogram

Horse Cladogram

“Unrooted” Phylogony of the Domains of Life

Major Steps in the Precambrian Evolution of Life 1.Origin of Life ( Gyrs) 2.Photosynthesis (3.5 Gyrs) 3.Aerobic (Oxygen-based) Respiration (3-2 Gyrs) 4.Eukaryotes / Endosymbiosis ( Gyrs) 5.Sex / Death (1 Gyrs) 6.Multicellular Life (800 Myrs) 7.Skeletons & Shells (600 Myrs) * All dates are approximate

Evolvovision Evolvovision (Ray Troll)