AP Environmental Science: Unit 2 Review - Biodiversity

Introduction to Biodiversity

• biodiversity - the variety of life in the world or in a particular habitat or ecosystem
• the more genetically diverse a population is, the better it can respond to environmental stressors
• species richness - the number of different species found in an ecosystem

Generalist and Specialist Species

• generalist - advantages in habitats that are changing, broad ecological tolerance, variety of food and environments (ex. raccoons)
• specialist - advantages in habitats that remain constant, narrow ecological tolerance, specific habitat and diet (ex. pandas)

K- and r- Selected Species

• K - selected species - usually large, few offsprings, mature after many years, long life span and life expectancy
• r - selected species - usually small, have Manu offsprings, mature early, short life spans
• biotic potential - maximum reproductive rate of a population in ideal condition

Ecosystem Services

• four types- provisioning, regulating, cultural, supporting
• provisioning - benefits to people, extracted from nature (ex. food, raw material, freshwater, medicinal)
• regulating - benefits provided by ecosystem (ex, pollination, air quality, biological control)
• cultural - non material benefit, development of people (ex. ecotourism, hiking)
• supporting - natural processes (all three services)

Ecological tolerance

• ecological tolerance -   range of conditions such as temperature, salinity, flow rate, and sunlight that an organism can endure before injury or death results

Island Biogeography

• island biogeography - study of the ecological relationships and distribution of organisms on islands, and of these organisms’ community structures
• highest species richness - near mainland
• lowest species richness - far mainland
• habitat fragmentation - a large expanse of habitat is transformed into a number of smaller patches of smaller total area isolated from each other (possible solution - habitat corridors)

Ecological Succession

• ecological succession - change in a community overtime
• primary succession - begins with lifeless area, bare rock, no soil, pioneer species (lichens) real rock to form soil
• secondary succession - disturbance alters community, soil already exists
• pioneer species - first specie to move into an unoccupied habitat during succession
• keystone species - significant role in the community (ex. otter)
• ecosystem engineer - organism that creates/destroys habitat (ex. beaver)
• indicator species - demonstrates the quality of an ecosystem with presence or absence (ex. corral)