1. Biodiversity

2. Biodiversity and Conservation
Variation in three levels:
Genetic – the variety of genes within a species
Species – the number of species per area
Habitat –the variety of places where life exists

3. Genetic Diversity Range of genes for a particular trait
May be different from another population of the same species
Definitely different from another species
Cause – sexual reproduction and mutations

4. Why is genetic diversity important?
Allows for survival from disease, changes in climate or other local environmental conditions
Provides the basis for evolution by natural selection
A healthy population has a high genetic diversity.

5. Habitat Diversity The range of different habitats
Includes microhabitat or a major community
Cause – Atmospheric circulation

6. Why is habitat diversity important?
Provides different niches
Provides a variety of services
CO2 Fixation
Pest Control
Nitrogen Fixation
Soil Binding
Air Pollution Absorption
Oxygen Production
Water Purification
Nutrient Storage
Pollination

7. Species Diversity
Species – organisms that interbreed and produce fertile offspring
How many different species are there?
~ 1.75 million known
Many more unknown
5 – 50 million or more

8. Interconnection of Diversity
Increases in types of habitat leads to increase in different species which in turn increases genetic variation.

9. Natural Selection Natural Selection
Darwin proposed that population changes are based on natural differences.
“Survival of the fittest”

10. Five main propositions for the theory of evolution by natural selection
More offspring are produced than will survive and reproduce.
There are more individuals than can be supported by resources of the habitat
There is competition for resources among offspring.
Struggle for survival based on environmental pressure

11. Five main propositions for the theory of evolution by natural selection
There is variation of traits within populations of organisms.
There is variety between individuals
Some of these traits are more helpful than others.

12. Five main propositions for the theory of evolution by natural selection
Because organisms with certain traits have greater chance of reproducing, there offspring will make up a larger part of the population
Those more fit (able)to survive, do and pass their genes on to the next generation
Changes in gene frequency lead to changes in population over time.
Over long periods of time consistent selective pressure along with reproductive isolation can lead to speciation (new species

13. Example of Natural Selection
Black and gray peppered moths in 19th century England