Paper 2 Ecology (Recap) Flashcards
(21 cards)
Habitat
Environment where the organism lives
Population
Total number of organisms of the same species living in the same geographical area
Community
Populations of all different species in the same habitat
Ecosystem
Both biotics and abiotic parts of the environment and how they interact with each other
What do plants compete with each other for?
Light, Space, Water and Mineral ions in soil
What do animals compete with each other for?
Food, Water, Mates, and Territory
Interdependence
All of the different species in a community depend on each other
Biotic factors
- Food (Availability)
- Arrival of new predators
- Competition between species
- New pathogens (Illness)
Abiotic factors
- Light intensity
- Temperature
- Water
- Soil pH + Mineral content
- Wind intensity + direction
- CO2 (Plants) and O2 (Aquatic life) levels
Factors of adaptation
- Structural (Body shape/Fur)
- Functional (Body temp. regulations)
- Behavioural (Nocturnal)
Producer
A green plant/Algae that synthesizes complex molecules (glucose from photosynthesis or biomass)
Primary consumer
A organism that eats producers (e.g herbivore)
Secondary consumer
Animal that eats primary consumers (Predators)
Explain how the populations of predators and prey change over the years
As the population of prey is high, the population of predators increases as there is more food. However, this results in a decline of the prey population, which causes the predators to starve so they too follow a decrease in population. The low number of predators allows the prey to repopulate and grow again in numbers, causing the cycle to repeat. HOWEVER! This type of system only works in a stable community where biotic and abiotic factors are in balance.
What is a quadrat and how is it used in random sampling?
A square frame which is placed on the ground, then the number of organisms inside are counted to sample plants or slow-moving animals
What is a transect and how is it used in random sampling?
A line made of either measuring tape or rope, which detects how populations change across a habitat. Place the transect across the investigated habitat before using a quadrat to count the number of organisms at intervals on the transect.
How to calculate total population size?
Total pop. size = (Total area/Area sampled) x No. of organisms of that species counted in sample
Explain the carbon cycle
Plants absorb CO2 in the atmosphere to use it for photosynthesis, leaving carbon. Some of the CO2 is respired by the plant and sent back to the atmosphere. Prey feed on the plants, and predators feed on the prey, passing the carbon to each other while respiring and returning CO2 to the atmosphere. When the animals release carbon in waste or death, some is decomposed by decomposers which release CO2 back to the atmosphere. However, some of the carbon waste is turned into fossil fuels and used by humans, which send CO2 back to the atmosphere through combustion.
Explain the water cycle
In the ocean, some of the water evaporates due to heat, forming water vapour in the air, which rises to form clouds. These clouds precipitate onto the ground. This rainwater either passes back to the ocean through rivers, evaporates into the air to form new clouds, or aquifers into the ground
Transpiration
Transfer of water in the plant, through the xylem tube in the plant’s stem
What are the factors for decay and why?
- Temperature (Energy is released when decomposers carry out aerobic respiration. A compost should not get too hot as enzymes can denature + decomposers die)
- Water (Many chemical reactions in decay require water, so a moisture is ideal)
- O2 Levels (Aerobic respiration requires oxygen, when not present, Anaerobic respiration occurs which releases a mixture of gases including methane, aiding global warming)
