1. Ch.5 - Evolution and Biodiversity
“Each species here today represents a long chain of evolution and plays a unique ecological role (niche) in the earth’s communities and ecosystems.”

2. 5-1 Origins of Life HOW DO WE KNOW???
Chemical Evolution – organic compounds and systems of chemical reactions formed the first cells. (took about 1 billion years!)
Biological Evolution – change from single celled prokaryotes
single celled eukaryotes
multicellular organism
HOW DO WE KNOW???
Most left behind fossil records that give us physical evidence of past organisms and their internal structures. Records are incomplete, however, and actually only represent about 1% of all species ever lived.

3. 5-2 Evolution and Adaptations
Evolution – change in a POPULATION’S genetic makeup over successive generations (not individuals!)
Theory of Evolution- all species descended from earlier, ancentral species
Macroevolution Microevolution
Long-term, large scale changes from 1
ancestral species to another where older
species is lost through extinction. Small genetic changes in a population’s gene pool that are past on to offspring.

4. Past organisms’ fossil records

5. 5-2 Changes in a Gene pool Basics of Genetics- Alleles
Mutations – environmental or random; harmful or beneficial
Create genetic diversity and new combinations of alleles

6. Beneficial and Lethal Mutations

7. Natural Selection
When individuals in a population have certain genetic traits that enhance their ability to survive and pass on these advantageous traits to their offspring.
Adaptation- heritable trait that enables the organisms to better survive under environmental conditions.
When faced with changing environmental conditions a species will either:
1) adapt through natural selection
2) migrate to areas with more favorable conditions
3) become extinct!

8. Coevolution
Interactions between 2 populations of different species over a long period of time can lead to changes in their gene pools, like a evolutionary contest of who can produce the most offspring.
Example: Bats and moths (echolocation)

9. 5-3 Ecological Niches & Adaptations
Niche– specific role in an ecosystem (occupation)
Includes:
adaptive traits
range of tolerance for physical/chemical conditions (temperature/H2O availability)
Types/amount of resources specie uses (food, space,etc)
How it interacts with nonliving/living components in the ecosystem
Role specie plays in energy flow and matter cycling in the ecosystem.
HABITAT- physical location where organism lives (address)

10. 5-3 Ecological Niches & Adaptations
Fundamental Niche – full potential range of physical, chemical, and biological conditions and resources a species could theoretically use if there was no t direct competition from other species.
Realized Niche- specie only occupies part of its fundamental niche to survive and avoid competition
Broad vs. Narrow niches = Generalists vs. Specialists

11. Coastal wetlands- specialized feeding niche

12. Fitness = reproductive success, not strongest!
Limits to Adaptations
Genetic trait that leads to an adaptation to changes in the environmental condition must already be present in the gene pool.
If present, adaptation is limited by reproductive rate. (humans would take thousands to millions of years to adapt!)
Fitness = reproductive success, not strongest!

13. 5-4 Speciation, Extinction, and Biodiversity
Allopatric speciation
Geographic isolation Reproductive isolation (Physical barrier) (no longer produces fertile offspring)
Sympatric Speciation
Mutation or changes in behavior no longer allows interbreed in close living species (insects)

14. Extinction 99.9% of all species that ever existed are now extinct.
Background extinction- species disappear at a low rate
Mass extinction and mass depletion
Extinctions create new opportunities for other species. Adaptive radiation sets in as new species adapt to fill vacated ecological niches in changed environments.

15. Human Activities are Decreasing Biodiversity
Richest areas of biodiversity- tropical forests, coral reefs, and wetlands

16. 5-5 What is the future of evolution?
Artificial Selection
Selective breeding
Genetic engineering
Genetically modified organisms (GMO’s) or transgenic organisms
Gene splicing
Biopharming- using genetically engineered animals to produce a product for human use
(hormones, vaccines, antibodies, etc.)
Bioethics- governmental regulations and control

17. Genetic Engineering

18. Why Humans Thrive as a Species
Strong opposable thumbs
Complex brains
Extra credit! (5 points)
See p. 100 Project #1 submit written assignment to me through by Monday!