Biodiversity
The total sum of all living organisms that exist on earth.
Genetic diversity
- diversity within species
- differences in DNA and traits
- Humans are species and all different in
- Blood type
- Hair, eyes, skin, color
- More genetic diversity=more biodiversity
Species diversity
- variety of species in a given area
- This map shows many different species in a given area.
- More species diversity= more biodiversity
Ecosystem diversity
- variety of habitats, ecosystems, and communities.
- Large areas of land with lots of different habitats or biomes.
- More ecosystem diversity=more biodiversity
Evenness
How close in number each species in an environment is
Richness
The number of different species in an ecosystem.
Evaluating richness and biodiversity
# closer to 0 is bad/low biodiversity # closer to 1 is good/higher diversity
Richness (total # of different species)
________________= biodiversity index
Total number of individuals at that site
Habitat Loss
- Habitat loss can include any reduction in habitat.
- # 1 threat to biodiversity.
- Land use changes (loss of habitat)
- Altering the land for a new purpose e.g. urbanization
•Habitat degradation (habitat may still be present but less habitable). Loss of quality.
Invasive Species
Introduced by humans intentionally or inadvertently.
- Harm human health, harm the environment and harm the economy.
- Can outcompete native (natural) species for resources.
- Are often less edible and provide little to no habitat or food resources to native species.
- Carry diseases
Pollution
Pollution contributes to habitat degradation and can poison species, as well as inhibiting growth and reproduction.
•Reduces air, soil and water quality.
Population growth of humans
- The human population is so large, we are displacing native species when we populate a new area.
Climate Change
Results from human caused increases in greenhouse gases.
- Seasonal timing problems (phenology)
- For example- species migrate but when they arrive their food source is unavailable or climate conditions are not suitable
Overexploitation/Overharvesting
Includes:
•over-hunting,
•over-fishing,
•poaching
Population
All members of the same species live together in the same place
Why do populations grow?
*more births than deaths
What increases birth?
*more individuals in a given area
Limiting factors-
prevent populations from experiencing unlimited growth
- predators
- food availability
- mate availability
- disease
Biotic factors
Climate
Natural disasters
Space
Abiotic factors
Exponential growth
- unlimited growth
- more births than deaths
- J-curve
Limited growth or logistic
*births eventually equal deaths
Carrying capacity:the most individuals a space can comfortably
*plateau on graph
