Ecosystems Flashcards
Habitat
A place where an organism lives
Population
All organisms of one species living in a habitat
Community
Populations of different species living in a habitat
Abiotic factors
Non living factors of environment
Biotic factors
Living factors of environment
Ecosystem
The interaction of a community of living organisms (biotic) with the non-living (non-biotic) parts of their environment
Where do organisms interact?
Within an ecosystem. Organisms compete for food, water, mate, reliance, mineral ions, etc.
What is interdependence?
When one organism relies on another
An example of interdependence
Pollination and seed dispersal
What does it mean if an area is biodiverse?
Lots of species. The community and ecosystem are stable.
What is a stable ecosystem?
Populations do not fluctuate and are more resistant to human activities and environmental change
How are feeding relationships represented in communities?
Food chains
What is a trophic level?
A part of the food chain
State the order of the food chain
Producer
Primary consumer
Secondary consumer
Tertiary consumer
Producer
Green plants and algae
Makes glucose via photosynthesis
Herbivore
Eats plants and algae
Primary consumer
Carnivore
Eats herbivore
Secondary consumer
Carnivore (2)
Eats other carnivores
Tertiary consumer
What is a predator?
A consumer that kills and eats other animals
What are prey?
Those eaten by predators
What is an apex predator?
A carnivore which has no predators
How does the predator-prey cycle look in a healthy, balanced ecosystem?
The numbers of each remain fairly constant.
Describe what happens when prey population increases.
- Prey increases due to more producers and less predators
- Predator population begins to increase (delayed, as it takes time for predators to catch prey and then reproduce)
Describe what happens when predator population increases
- More prey hunted, prey population decreases
- Predator population decreases as there is less prey to hunt
What is biomass?
The mass of living material. Pyramids of biomass represent relative amounts of biomass in each level of a food chain.
Describe a pyramid of biomass
Producers are at the bottom
Primary consumers above
Secondary consumers above
Tertiary consumers
How do you calculate biomass lost
Lower trophic level biomass - Higher trophic level biomass
How do you caluculate efficiency of biomass
Higher / Lower * 100
Biomass is ** between each trophic level
Lost
Approximately 10% of the biomass from each trophic level is transferred to the level above it
Why is biomass lost between trophic levels
- Not all of organism is edible
- Some absorbed material egested as faeces
- Lost as waste e.g. CO2, H20, urea
- Used for respiration
What is a transect?
Measures the distribution of a species over a distance
Why would a transect be performed
Seeing if environmental factors affect where species lie along the transect
What can we measure along the transect
Light intensity (lightmeter)
Temperature (thermometer)
Soil pH (Indicator)
Width of leaves (ruler)
Method of transect
1) Lay out a tape measure of (desired) area
2) Place a quadrat continuously along the tape measure or every other metre
3) Count or identify species in the quadrat
4) Use a meter to measure an abiotic factor (if measuring how that factor affects distribution of a species, e.g. temperature)
Always measure at the same height/direction e.g. light meter placed in same direction facing upwards
Repeat by completing another transect further along the habitat
Repeat transect at different times of the day/year/seasons
What is random sampling?
Estimate the population of a species in an area / investigate biodiversity (variety of species) in an area
Quadrats are placed randomly, using random coordinates
to reduce bias
How do you random sample
1) select a sample area within a habitat
2) create a grid/axis using tape measures to create a sample area
3) use random coordinates to place a 1m x 1m quadrat if investigating plants or animals that dont move
3) for animals, you can use traps, e.g. pitfall traps (insects) sweep nets (flying insects) camera traps, etc.
4) identify number of species within the quadrat and count number of organisms
5) repeat minimum 10 times
6) repeat in a different location within the same habitat / other times of the day or year or seasons to improve reliability (spot anomalous results)
What is an adaptation
Enables an organism to survive in their natural environment
What is a a structural adaptation
Shape or colour
e.g. Scales / Skin for camouflage to avoid being spotted by predators OR to sneak up on prey
What is a behavioural adaptation
The way organisms behave
- Remain in a herd = Less likely to be eaten
- Hunting in packs = Increased hunting success
Functional adaptation
Internal adaptation
- Adrenaline in fihgt or flight = More likely to survie a confrontation w a predator
- Immune system prevents illness caused by pathogens
- enzymes break down food
- poison in skin deters predators
Extremophiles
Organims adapted to extreme environments e.g. volcanic vents, nuclear reactora
What is black smoker bacteria
Found on deep sea volcanic vents. Heat resistant enzymes that dont denature
Adaptations to cold environments
Reduce heat loss =
- Thick furs to insulate heat
- Thick layers of fat to insulate heat
- Small surface area : volume ratio to reduce heat los
Adaptations to cold environments
Increase heat loss =
Plant adaptations
Structural behavioural functional
Structural in plants
Waxy cuticle = prevents water loss
Less stomata = Less transpiration = Less holes for water to diffuse throughOth
Other plant adaptations
- Poisonous to prevent eaten
- Large flowers attract pollinators
What is competition
Plants and animals compete with each other for resources
What do plants compete for
Light, mineral ions in salt and water
e.g. Weeds removed by farmers using herbicides
Why do farmers remove weeds
Results in lower crop yield
What do animals compete for
Space, food, water, mates
e.g. Male robins compete for territory in English gardens
Intraspecific competition
Between the same species
Interspecific competition
Between different species
What happens if one organism outcompetes another
Species becomes extinct e.g. grey squirrels outcompeting red
Why do populations fluctuate
Organisms eat each other
Photosynthesis in carbon cycle
- Plants remove CO2 from the atmosphere through their stomata
- Plants use CO2 for photosynthesis to make glucose (carbon compound)
- Glucose can be used to make other carbon based compounds (e.g. carbs, proteins, lipids, cellulose)
- Some glucose is stored as starch
Feeding in carbon cyclr
- Animals eat plants
- C passed along food chain
- Animals use some C compunds consumed to make other C compounds
(carbs protein lipids)
Decay in carbon cyclr
- Plants and animals are decayed by microorganisms
- Microorganisms use the C compounds to make other C compounds
- Microorganisms respire to release CO2
Respiration in carbon cycle
- Plants animals microorganisms respire
- Release CO2 back into atmosphere
Fossil fuels in carbon cycle
- Remains of decayed plant and animal matter become fossil fuels
- Combustion of fossil fuels releases Co2 into the atmospherw
Nutrient cycle
- Plants and animals die to produce organic matter
- Microorganisms cause decay in warm and moist conditions
- These produce nitrates and other mineral ions
- Roots of plants absorb the nitrates
Repeat
Decay by microorganisms
- Microorganisms break down (decay) plant and animal material waste for energyhat
What affects the rate of decay
a) High oxygen levels
b) High moisture levels
c) Warm conditions
Why is decay important
Farmers provide optimum conditions for the rapid decay of biological material
Compost (full of mineral ions) is used as a natural fertiliser for growing garden plants and crops
What is biogas
Anaerobic decay produces methane gas
Methane gas used as fuel
