Biodiversity 1 and 2 - T Flashcards
The biosphere
all biodiversity and biological functions, interactions with other Earth systems
has evolved over time and altered other components of the Earth system
functional definition of life (4)
carry out metabolic reactions
defend itself against injury
respond to stimuli
reproduce itself
minimum criteria for defining life
able to acquire nutrients
metabolize energy (waste), reproduce, evolve
what does life need (3)
constant input of energy (From sun or hydrothermal vents)
water needed for metabolism
carbon and 5 other elements
impact of evolution of oxygen-producing life on the atmosphere (2)
oxygen increased CO2 reduced further
developed the ozone layer which screens out UV radiation
Impact of an oxygenated atmosphere on the evolution of life
4
ozone layer allowed life to flourish on land
reduced dominance of anaerobic bacteria
evolution of more efficient types of energy use (mitochondria)
development of larger animals which required more oxygen
what controls the distribution of biomes? (3) what biome doesn’t exist
temperature, precipitation, seasonality
cold and rainy
Actual evapotranspiration
combines effects of temperature and precipitation
high = warm and wet (tropical rainforests)
low = dry or cold
strongly correlated with NPP
NPP differene between tropical and temperate forest
daily vs yearly
daily is similar but the yearly NPP is much higher for tropical, meaning the growing season is much longer a big factor here
Biodiversity definition + components (6)
variety of life at all levels and the ecological and evolutionary processes that sustain it
species, genetic diversity, population structure, communities, ecological processes, ecosystems
species richness
number of species within a habitat
increases with area, towards tropics, and declines with elevation
why does species richness increase toward the topics (5)
1) greater land mass (more area means more species)
2) less harsh of a climate
3) more stable climates
4) species-energy hypothesis: greater exposure to solar energy means greater productivity means more species can be accommodates in food webs
5) causes more higher speciation rates
facts about extinctions
extinctions are common (0.1% are extant today)
species with small populations or small ranges are easy to kill
widespread species are hard to kill, need widespread stressor that are not normally experienced
to kill many species, the stress must be applied over a wide area
why do small populations have high extinction risk (4)
demographic stochasticity (minor glitches)
small gene pool
population is spread too thinly
vulnerable to small-scale environmental stresses
causes of prehistoric mass extinctions (3)
think natural disasters
asteroid –> wildfires, tidal waves,
volcanic activity
fall in sea level (reduces marine habitat area)
global climate change
