Topic 7 - Ecology Flashcards
What is the difference between a population, community and ecosystem ?
Population = one species
Community = many populations interacting in same habitat
Ecosystem = interaction of community with abiotic factors of the environment
What might organisms compete for ?
Plants : light, space, water, mineral ions
Animals : space, food, water, mating partners
What are 7 abiotic factors which affect a community ?
Light intensity, temperature, moisture levels, soil pH, wind intensity and direction, carbon dioxide levels, oxygen levels
How does light intensity affect a community ?
- light is required for photosynthesis
- which affects the rate at which plants grow
- organisms use plants for food sources or shelter
How does soil pH and mineral content affect a community ?
- soil pH affects the rate of decay and therefore how fast mineral ions return to soil
- different species thrive in different nutrient concentration levels
How does wind intensity and direction affect a community ?
- wind affects the rate of transpiration which affects the temp of a plant, and the rate of photosynthesis
What are some biotic factors that affect communities ?
- food availability - more food means organisms can breed more successfully and population can increase
- new predators
- new pathogens - population has no resistance and it can be wiped out quickly
- competition - if one species is more adapted to an environment it will outcompete the other until it’s insufficient to breed
What are the 3 types of adaptions and give some examples ?
Structural :
Shape or colour of a part of an organism
- sharp teeth on a carnivore
- camouflage
- thick layer of fat for insulation
Behavioral :
- playing dead
- basking in sun to absorb heat
- courting behavior to attract a mate
Functional :
- late implantation of embryos
- conservation of water through producing little sweat
What are extremophiles and give an example of?
- organisms which live in environments with extreme conditions such as high temps, pressures or salt concentrations
- bacteria which live deep in sea vents where the pressure is very high
Give some examples of adaptions in cold climates ?
- smaller surface area to reduce heat loss
- insulation such as blubber or fur
Give some adaptions for dry climates ?
- adaptions of kidneys so they retain lots of waters
- being active in mornings and evenings
- resting in shady places
Give some examples of plant adaptions ?
- curled leaves to reduce water loss
- extensive root systems to take up lots of water
- waxy cuticle to stop water evaporating
- water storing tissue in stem
What are the parts of the food chain ?
- producer
- photosynthesis to make glucose
- primary consumer
- secondary consumer
- Tertiary consumer
What is the difference between predators and prey ?
- predators kill and eat other animals
- those who are eaten are killed prey
What tools can be used to work out the distribution and abundance of species ?
- transects
- quadrates
What will happen if the population of prey increases ?
- population of predators will also increase
- number of prey would then decrease as they’re consumed by the predators
- when there isn’t enough prey to feed all the predators the population of predators will decrease
- this allows the population of prey to once again increase
Describe the carbon cycle ?
- CO2 is removed through photosynthesis of green plants and algae
- these plants are consumed and the carbon moves up the food chain
- CO2 is returned to the air during respiration
- Decomposers additionally respire while they return mineral ions to the soil
- CO2 is returned to the air when wood and fossil fuels are burned (combustion)
Describe the water cycle ?
- the sun causes water to evaporate from the sea and lakes causing water vapor
- water vapor is additionally formed as a result of transpiration of plants
- water vapor then rises and condenses to form clouds
- water is returned to land by precipitation and this runs into lakes to provide water for plants and animals
- this also runs into the sea and the cycle continues
What factors affect the rate of decomposition ?
- temperature (warmer conditions are better but if too hot enzymes can denature and stop decomposition)
- water (water needed for respiration)
- availability of oxygen (most respire aerobically
What do biogas generators produce and what conditions ?
Methane gas
Requires a constant temperature of 30 degrees so microorganisms keep respiring
Needs to be used immediately as it cannot be stored as liquid
How can you investigate the effects of temp on decay by measuring the pH change of milk in the presence of Lipase ?
- make a solution of milk and phenolphthalein indicator
- add sodium carbonate which will cause the solution to become alkaline and therefore pink
- place the tube in a water bath at a specific temperature
- add the lipase enzyme and begin stopwatch
- time how long it takes for the pink color to disappear
- repeat this at different temperatures to see at which temperature the pink temperature disappears the quickest indicating the quickest decomposition
What environmental changes affect the distribution of species ?
Temperature, climate change may lead to insects migrating to places in the world becoming warmer
Water availability, populations migrate to find water
Atmospheric gas composition, certain pollutants affect the distribution of organisms
Biodiversity definition ?
The variety of different species of organism on earth or within an ecosystem
How have humans decreased biodiversity ?
- more land being used for houses, farming, shops, factories which destroys habitats
- pollution killing plants/animals such as sewage, fertilizer polluting water or landfill and toxic chemicals polluting land
- we are using up raw materials faster than they’re being produced
