Environmental Science FIRST EDITION Andrew Friedland Rick Relyea © 2012 W. H. Freeman and Company CHAPTER 5 Evolution of Biodiversity

F. assafoetida – Dung of the Devil

Nature’s Pharmacy Rosy periwinkle

Species Diversity …in a healthy forest

Plantation -v- Forest

Ecosystem Diversity Genetic Diversity Species Diversity

Species: A population of organisms With shared characteristics Capable of interbreeding, and Producing fertile offspring In nature

How diverse are insect populations in the rainforest? What group of insects is most abundant? Where do most insects reside within the rainforest?

Species Richness -v- Evenness

Derived Trait

Environmental pressures affect phenotype

Artificial Selection

A mechanism to explain how evolution works Principles of Natural Selection

Over-reproduction Producing more offspring than can possibly survive in nature Why would an organism waste all of this energy? Because many will not survive, (life’s hard!!), having many offspring ensures that at least some will survive

Variation Organisms have differences in the their phenotypes, their characteristics. We’re not all identical!! Sources of variation: 1.mutation 2.meiosis: a.Crossing over b.Independent assortment 3.Sexual reproduction

Struggle for Survival Organisms must compete for limited resources What do they compete for? 1.Food 2.Water 3.Mates 4.Territory 5.Shelter

Survival of the Fittest Only those organisms best adapted to their environment can survive (and pass on their DNA!) What will happens to populations of organisms over time? A population becomes better suited to its environment.

What makes an organism/population/species fit? Adaptation: –A structure, behavior or internal process that makes an organism better suited to its environment Evolution: –Occurs to a population (species), not an individual

Hardy Weinberg Equation p 2 + 2pq + q 2 = 1 What does this mean? A population is comprised of the sum of its various genotypes, and this should remain constant. But it doesn’t remain constant. Ever. It does give us a baseline from which to evaluate change. What factors cause the frequencies of genotypes to change?

Allopatric Speciation

EURASIA AFRICA SOUTH AMERICA INDIA 135 million years ago Present 65 million years ago 225 million years ago 120° 80° 0° 120 ° 80° 40° 120° GONDWANALAND 120 ° LAURASIA PANGAEA ANTARCTICA AUSTRALIA NORTH AMERICA

Sympatric speciation through polyploidy

Ability of a Species to Adapt to Change

……R and K strategists, coming soon

Range of Tolerance for a Species Just one of many factors

Is it better to be a generalist?

…or a specialist?

How do we collect this data?

Predicting Future Species’ Distribution

The Fossil Record

Mass Extinctions & Explosions of Life

An FRQ, to ponder.