Unit 2 - Biodiversity

human activity leads to disruptions of natural processes, having economic and ecological consequences
^^environmental worldviews^^: anthropocentric or ecocentric (balance is biocentric)
^^sustainable development^^: using resources in a way that fulfills human needs but does not deplete their quantity for future generations (profitable)

==Provisional==: resources directly derived from sources in nature
- most basic of all ecosystem services
- ex. water, food, plants, fuels, timber, herbal medicine
==Regulating==: processes that maintain natural phenomena to be clean, functional, and resilient
- essential for human survival; costly to replace
- ex. air/soil quality, pollination, water flow, carbon sequestration
==Cultural==: abstract concepts/ideas that contribute to the cultural/theoretical development of human society
- not a necessity for basic human survival
- ex. knowledge, sports, sense of place, aesthetics, art
==Supporting==: basic natural processes that sustain life on Earth
- the foundation of all other processes
- ex. photosynthesis, water cycle, nutrient cycle

study of ecological relationships and distributions of organisms on islands + their community structure
- created by Caral Linnaeus (1707 - 1778) Charles Darwin (1809 - 1822), Alfred Russel Wallace (1823 - 1913)
@@species richness@@: # of species in an area
@@species evenness@@: comparison of pop. of species
Robert McArthur & EO Wilson (1967)
- @@Highest species richness@@: large islands near the mainland
- @@lowest species richness@@: small islands far from the mainland

physical and geographical disruption of various environments caused by human activity
- → l^^oss of apex predators^^ (ie. wolves, bears, etc.) and more specialist feeders
- → ^^increase in # of organisms of generalist feeder species^^ (can easily adapt to changes in food sources and other resources)
- limits %%migration%% for isolated species in different biomes
- human activity (agriculture and societal development) → increase in habitat fragmentation → separation of species
solution: ^^habitat corridors^^ (connecting fragmented habitats through animal-friendly tunnels or bridges = easier migration & greater diversity)

range of %%abiotic conditions%% (temperature, sunlight, salinity, etc.) that an organism can %%endure%%
- measured on a bell curve
- %%> range%% (below avg range of ecological tolerance) = reduced fitness; inability to thrive/reproduce

ecological impact of ^^natural^^ disruptions >= ecological impact of ^^human^^ disruptions
^^natural processes^^: quick vs short-term
- periodic: one event → long-term effect/event
- episodic: sudden event → greater effects/events over time
- random: sudden, w/o leading cause

has changed over time thru %%geological shifts%%, including:
- amount of solar radiation reaching the Earth
- changes in atmospheric composition (ie. greenhouse gases, ozone layer depletion)
- rising sea levels due to melting glacial ice

^^seasonal movement^^ of animals from one habitat → another habitat
- adaptative response for %%better opportunities for resources and matin%%g
- varies greatly by the organism
- ex. birds migrate from the Northern Hemisphere → Southern Hemisphere annually

organisms adapt to their environment over time (short & long-term scales) through ^^incremental genetic changes^^, leading to:
- %%physical changes in appearance%%
- ex. peppered moths (lighter body tones → darker body tones)
- %%biochemical changes%%
- ex. pesticide resistance (mutations in the genes of pests cause pesticides to become ineffective), natural selection
adaptations persist in an organism species if it is advantageous to their survival in the environment → reproduction to pass similar genes to offspring
gene must be present BEFORE the environmental change

sudden or gradual environmental changes → endangering lives of different species in habitat:
- changes in behavior (adaptation)
- migration
- extinction
- ex. climate change → extinction of dinosaurs, deforestation → dislocation of species
organisms with a %%selective advantage%% will be better at adapting and surviving in a new environment

a gradual process where %%community structure changes%% (typically replacement of community)
- affects the total biomass, species richness, and net productivity
- ex. changes in predominant plant community → habitat/wildlife change
- ^^biomass^^: larger plant species have more biomass than smaller plant species (material & weight)
- ^^richness^^: greater in previously distributed species; less in recently distributed species
- ^^productivity^^: more biomass → higher rates of photosynthesis (a measure of productivity)
primary succession: a new area is dominated by pioneer species (lichens)
- rock → soil formation & initiating plant growth
- caused by human or natural disruptions
- primary succession + adaptation over time = origin of new species
pioneer species: ^^broad range^^ of ecological tolerance to survive ecological disturbances
- adaptable; can quickly pass on genetic traits; supports the emergence of new species
secondary succession: new species take over old land (still filled with soil)
- also caused by human or natural disruptions
keystone species: plays a significant role in ^^determining^^ community structure
- ex. otter, sea urchin, kelp
ecosystem engineers: organisms that alter habitat beneficially
- ex. beavers
mutualists: two organisms interact for mutual benefit
indicator species: represents aspect or quality of an ecosystem is present
- has a ^^narrow range^^ of ecological tolerance
- ex. amphibians