1. Population Changes and Natural Selection

2. Biodiversity
Biodiversity, or biological diversity, is the sum of an area’s organisms, considering the diversity of species, their genes, their populations, and their communities.
A species is a particular type of organism; a population or group of populations whose members share certain characteristics and can freely breed with one another and produce fertile offspring.

3. Biodiversity
Costa Rica’s Monteverde Cloud Forest is home to many species and possesses great biodiversity.
Figure 5.1

4. Abiotic Factors Biotic Factors
All of the living organisms within an ecosystem
Examples:
Plants
Animals
Fungi
Any other living things
All of the non-living things in an ecosystem
Directly affect how organisms survive
Examples:
Amount of Water
Temperature
Acidity of Water
Weather
Natural Disasters

5. Limiting factors
Environmental factors that limit population sizes in a particular environment
Examples:
Food
Water
Predators
Temperature

6. How Population Changes Happen
Charles Darwin
Developed the theory of evolution
Different birds had different beaks – They each adapted to a different island environment.
Speciation
Formation of a new species as a result of change over time

7. Natural Selection
The process by which individuals that are better adapted to their environment survive and reproduce
Individuals who do NOT adapt are less likely to survive and reproduce

8. Natural selection
Fitness = the likelihood that an individual will reproduce
and/or
the number of offspring an individual produces over its lifetime
Adaptive trait, or adaptation = a trait that increases an individual’s fitness

9. Natural selection Evidence of natural selection is all around us:
In nature …
Diverse bills have evolved among species of Hawaiian honeycreepers.
Figure 4.23a

10. Beak Types Resulting From Natural Selection
Unknown finch ancestor
Insect and nectar eaters
Fruit and seed eaters
Greater Koa-finch
Kona Grosbeak
Akiapolaau
Maui Parrotbill
Kuai Akialoa
Amakihi
Crested Honeycreeper
Apapane
Beak Types Resulting From Natural Selection

11. Natural selection
Evidence of natural selection is all around us:
… and in our domesticated organisms.
Dog breeds, types of cattle, improved crop plants—all result from artificial selection (natural selection conducted by human breeders).
Figure 4.23b

12. 4 Steps of Natural Selection
Overproduction
Inherited variation
Struggle to survive
Successful reproduction

13. It’s been said that every person on the planet, around 6,2 billion of us, could fit into the state of Texas.
How would life be if everyone lived in TX? Describe what you believe it would be like. Explain.
Cougar Hunt