Population Ecology & Succession, Nutrient Cyles , Pollution Flashcards
When the number of organisms rises at an ever -increasing rate
Exponential growth
Number of organisms that a particular environment can support over an indefinite period of time ( births will exceed deaths until carrying capacity is reached )
Carrying capacity
What are the four types of growth graphs ?
-exponential (aka unrestricted growth)
- boom and bust
+ logistic (restricted growth )
+predator /prey
Have an increasing effect as population increases
E.g., disease, parasites, competition, crowding, and stress
Density dependent
Affects all population, regardless of their density . Usually abiotic facts
E.g., storms, floods, temp, fire
Density independent
Species living in an area to which they are not native. Can be introduced accidentally or on purpose
E.g., sika from Asia brought to south TX
Exotics
Name 3 negatives effects of exotics
Not native to an ecosystem
No natural predators
Can outcompete native species for resources
The predictable changes that an environment goes through as its being established or redeveloping
E.g., competition for light / any nutrients
Succession
Occurs in areas where no ecosystem or biological activity has existed previously, without any soil ( can take 100s and 1000s of years )
Primary succession
What are the 5 stages of primary succession?
- Pioneer species -lichens
- Mosses and ferns
- Grasses
- Shrubs and small softwood trees
- Large hardwood trees (climax community )
Pattern of change in areas where logical activity or an ecosystem has previously existed; already has soil and was once the home of living organism . Is faster and only stages 2-5
E.g., forest fires, floods, deforestation
Secondary succession
Is this primary or secondary succession ?
Begins with no life
Primary
Is this primary or secondary succession ?
Follows removal of existing biota
Secondary
Is this primary or secondary succession ?
No soil present
Primary
Is this primary or secondary succession ?
Soil already present
Secondary
Is this primary or secondary succession ?
New area
Primary
Is this primary or secondary succession ?
Old area
Secondary
Is this primary or secondary succession ?
Lichen and moss come 1st
Primary
Is this primary or secondary succession ?
Seeds and roots already present
Secondary
Is this primary or secondary succession ?
Biomass is low
Primary
Is this primary or secondary succession ?
Biomass is higher
Secondary
Critical to homeostasis
E.g., top predators (sharks,mountain lions ), hummingbirds, pollinates
Keystone species
Stable ecosystem in equilibrium or steady state
Climax community
Matter and nutrients recycled through an ecosystem
Energy, however, is replenished by the sun
Nutrient cycles
Occurs on Earth as a solid, liquid, and gass
Precipitation →accumulation → evaporation →condensation
Water cycle
-Is found in all living things -organic molecules
-CO2 is taken up by photosynthetic organisms that travel through the food chain
- carbon is released through CO2 in respiration and burning of fossil fuels (combustion)
Carbon cycle
- makes up almost 78% of air
- every living organism needs it to make proteins and nucleic acids (DNA/RNA)
- nitrogen fixation by lighting and bacteria
Nitrogen cycle
-Many organism cannot direct use nitrogen to make protein and DNA .
- bacteria living o rocks and legumes concert N to NH3 (ammonia)
- NH3 is then passed from consume to consumer along the food chain
Nitrogen fixation
Bacteria produce nitrogen gas
Denitrifying
Predation
Keeps population size within limits (density dependent )
