Ecology Flashcards
Steady state is reached when…
Number of organisms in a population is just less than the carrying capacity
Abiotic factors that effect populations
- light
- temp
- chemical environment
Biotic factors that affect the population
- food
- number of predators
- diseases
- ability to compete
Biotic potential
Max number of offsprings that a species could produce if resources were unlimited
4 important factors of biotic potential
- birth potential
- capacity for survival
- procreation
- length of reproduction life
Formula for growth rate
births-deaths+immigration -emigration
Divided by initial population size
Density dependant factors
Those that have an increase or decrease depending on the number of organisms in an area
Ex: predation, disease, food
Density independent factors
Those that affect the population regardless of the population density
Ex: climate, human intervention, natural disasters
Population size changes due to:
Natality (births)
Mortality (deaths)
Immigration (move INTO a population)
Emigration (move OUT of population)
Bio accumulation
Some pesticides are insoluble in water. These toxins cannot be released from the body in sweat or urine. Toxins build up in fatty tissue.
Bio amplification
Pesticides in organisms in the lower food chain pass their toxins to their consumers
Types of pesticides
Herbicide
Insecticides
Fungicides
Pesticides are useful because…
- Prevent damage to crops
- top spread of disease
- prevent disintegration of products
Biosphere
Where life exists
- biomes create biosphere
Organic substances
Always contain atoms of carbon and hydrogen
Occasionally oxygen and nitrogen
Water cycle
Transpiration -water vapour from trees
Evaporation-water vapour from bodies of water
Respiration- water vapour from breathing
Carbon cycle
- plants use carbon dioxide in photosynthesis
- cellular respiration releases carbon dioxide back in to environment
- decomposition
- fuel burning
Reservoirs for inorganic carbon
Atmosphere
Ocean- co2 reacts with sea water to form carbonates
- combine with calcium to form shells
Earth’s crust - sediments
Reservoirs for organic carbon
- in bodies of living things
- decomposition
Human impact of carbon
- mining
- burning fossil fuels
- burning forests
- clearing vegetation
Nitrogen cycle
Nitrogen in atmosphere (N2)
Useful nitrogen is in form of nitrate ion (NO3) called Nitrogen fixation
Absorbed by plants
Decaying plants and animals (ammonia)
Denitrification
Nitrogen fixation occurs in
Lightning and bacteria
Soils are…
- Essential in ecosystem
- part of
Lithosphere - depended by animals and plants
Soil profile
Top soil
Sub soil
Bed rock
Water table
Top soil contains
Humas
Rocks
Organisms
Sub soil is
Compact
Little organic matter
Large rocks