ESS General Session 3 Revision, Biodiversity and Mass Extinctions

Biodiversity

Refers to the variety of life forms within a given ecosystem, biome, or the entire Earth, encompassing species diversity, genetic diversity, and ecosystem diversity.

Define Species diversity:

Outline why it is important:

The variety of a species within an ecosystem:

• Increases ecosystem inertia

• More species can serve as natural capital for humans

Define Genetic Diversity:

Outline why it is important:

The variation of genes within a species:

• Important to reduce inbreeding within populations that lead to birth defects

• Important to allow species to adapt to new environments/ecosystems or to survive extinction events

Explain the relationship between Natural Selection and Speciation:

Natural selection is the process in which isolation, or environmental stress causes species to accumulate genetic differences over time. The genetic differences which are caused by natural selection, isolate populations reproductively so that certain genetic information and traits which carry over to the next generation do not allow these populations to interbreed.

Biodiversity hotspots

Regions with a high concentration of endemic (unique) species which are under threat from humans.

Mass extinctions links:

They are linked to natural factors such as climate shifts, volcanic activity, meteor impacts, and sea-level changes.

Adaptive radiation

The process in which the populations of surviving species from a mass extinction begin to reproduce in depopulated areas, resulting in speciation or that species filling in new ecological/niche roles within that particular ecosystem.

Briefly outline Human-induced threats to biodiversity (HIPPO)

• Habitat destruction→ Loss of habitats for a variety of species from deforestation or agriculture

• Invasive species→ External species that outcompete the native species which may result in trophic collapse

• Pollution→ Contamination of ecosystems (Bioaccumulation, Biomagnification) interfering with energy systems/productivity

• Population growth→ Increased human populations require more resources

• Overexploitation→ The rapid harvesting of resources or a particular species that is faster than the rate at which it can reproduce, causing extinction/rapid depopulation

Define Fragmentation:

Outline why it has a negative effect on the environment:

The division of habitats into smaller, isolated pockets of species

• Reduced biodiversity (especially genetic and species)

• Reduced natural services from ecosystem

• Reduced wildlife interconnectivity

Vulnerability factors for a species:

Narrow range (geographical, population), specialized diet, small population, low reproductive rate.

Effects of climate change on Biodiversity:

Alters migration, breeding patterns, and distribution of species.