Biodiversity ENVS141

What is biodiversity

the variety of life in the world or in a particular habitat or ecosystem.

Short for biological diversity
Genes/life/ecosystem on the planet
The complete variety of species and genes within all of the ecosystems on earth

Three levels of biodiversity are:

Genetic, species, ecosystem diversity

Ecosystem

The interaction between living and non-living things within an area.

Species diversity

All of Earth's species

- Reflects evolutionary history of life
- Each species plays a unique role in the ecosystem
Ex. food web
- Provides resources for people
- Pollinators - allow agriculture to thrive/bring food
- Forest helps - soil stability, lumber,

genetic diversity

Variation in genes within a species, for all species

- Ex. rabbits with different genetic traits (breeds)
- Reflected in variation among individuals
- Determines evolutionary potential and species' ability to adapt to new environmental conditions
- Reflects adaptations/natural selection
- Ensures resources for people in the future
- Disease resistance within species used for food and other resources

ecosystem diversity

All of the different biological communities on Earth result from their associations with the non-living components (geology, chemistry...) in their local environments

- Provides ecological services for people
- Clean air, clean water, climate control, storm protection
- Ex. salt marshes, mangroves

Speciation

Evolution of new species
Increases biodiversity by adding new species

Extinction

- Loss of species (or genus, family, or other higher taxonomic group)
- Decreases biodiversity by eliminating species
- (1) Kingdom; (2) Phylum or Division; (3) Class; (4) Order; (5) Family; (6) Genus; (7) Species

How many mass extinctions have there been?

5 mass extinctions

Late Ordovician Extinction

- 447-443 million years ago
- 49% of genera went extinct
- Global cooling, glaciation, and sea level decline are associated with the major land mass movement

Late Devonian Extinction

- 375-360 million years ago
- 50% of all genera went extinct
- Cause is unclear but related to environmental changes (Climate, air composition)

Late Permian Extinction

- 252 million years ago
- Largest known extinction
- 83% of all genera went extinct
- Cause is unclear but likely includes meteor impact/s, increases in greenhouse gases leading to climate change, and sea level rise
- Similar to now, We are increasing the rate, making this the fastest mass extinction known
- This happened over a very long time period

Late Triassic Extinction

- 201 million years ago
- At least 50% of all species went extinct
- Cause unclear
- Ushered in the age of the dinosaurs

Late Cretaceous

- 66 million years ago
- >75% of all species went extinct including all non-flying dinosaurs
- Astroid collision
- Ushered in the age of the mammals

Current mass extinction event

- biodiversity crisis
- 60% decline in animals on Earth in the last 40 years
- Cause: people

Species extinction rates

> 1000 times background rate

Major drivers of wildlife decline

Exploitation - 37%
Climate change - 7%
Habitat degradation/change - 31%
Habitat loss - 13%
Other - 11%

3 goals of conservation biology

1. Document biodiversity
2. Determine our impacts on biodiversity
3. Determine how to protect and conserve biodiversity

Conservation biology

Value-driven, multidisciplinary science

Ethical principals of conservation biology

- Biodiversity should be conserved
- Human-driven extinctions should be prevented
- Maintain ecological complexity
- Maintain evolutionary capacity
- Biodiversity has intrinsic value

Human population growth

- Rapid growth
- More people = more resource consumption
+ Ecological footprint
- Biodiversity loss = bad for people
- We can't survive without other species
- Poorest people hurt the most
+ Environmental justice