Ecology

• HABITAT- the place where an organism lives
• POPULATION- all the organisms of one species living in habitat
• COMMUNITY- the populations of different species living in a habitat
• ABIOTIC FACTORS- nonliving factors of the environment
• BIOTIC FACTORS- living factors of the environment
• ECOSYSTEM- the interaction of a community of living organisms with the nonliving parts of their environment
• Organisms need things from their environment and other organisms to survive and reproduce
• Plants need light and space, and water and mineral ions from the soil
• Animals need space (territory), food, water and mates
• Organisms compete with other species (and members of their own species) for the same resources
• In a community, each species depends on other species for things- interdependence
• The interdependence of all the living things in an ecosystem means that any major change (such as one species being removed) can have far-reaching effects
• Blackfly larvae-less competition for algae-increase
• Water spider-less food-decrease
• Stickleback-less food (if the other numbers decrease)-decrease
• In some communities, all the species and environmental factors are in balance so the population sizes are roughly consistent
• These communities are called stable communities-stable communities include tropical rainforests and ancient oak woodlands
• Abiotic factors are nonliving factors such as moisture level, light intensity, temperature, carbon dioxide level, wind intensity and direction, oxygen level, soil pH and mineral content.
• Sometimes poor soil is the main reason crops fail, so even GM ones won’t survive.
• There are fears that countries may become dependent on those who sell GM seeds.
• Biotic factors are living factors such as new predators, competition, new pathogens, availability of food.
• A change in the environment could be an increase or decrease in abiotic factors, which can affect the size of populations, so can affect the populations size of dependent organisms.
• A decrease in light intensity, temperature or CO2 can decrease the rate of photosynthesis, which can affect plant growth and cause a decrease in population size.
• A decrease in the mineral content of the soil can cause nutrient deficiencies, which can affect plant growth and cause a decrease in population size.
• Organisms, including microorganisms, are adapted to live in different environmental conditions, these features or characteristics that allow them to do this are adaptations.
• Structural adaptations can be features of an organism's body structure (shape or colour), such as the white fur of arctic animals to camouflage against the snow, or the thick layer of blubber and low surface area to volume ratio of animals that live in cold places to retain heat.
• Behavioral adaptations are ways that the organism behaves, such as migration to warmer climates during the winter to avoid the problems of living in cold conditions.
• Biogas can’t be stored as a liquid (pressure needed is too high), so it has to be used straight away.
• The rate of decay can be calculated using the formula:RATE=1000/TIME.
• These materials are returned to the environment in waste products.
• CO2 is removed from the atmosphere by green plants and algae during photosynthesis.
• The combustion (burning) of food and fossil fields also releases CO2 back into the air.
• The carbon (and energy) is constantly being cycled-from the air, through food chains and eventually back out into the air again.
• You can also calculate the efficiency of biomass transfer between trophic levels: EFFICIENCY=BIOMASS TRANSFERRED TO THE NEXT LEVEL/BIOMASS AVAILABLE AT THE PREVIOUS LEVEL x100.
• Living things are made of materials they take from the world around them.
• Net size is a limit of mesh size depending on what’s being fished, to reduce the number of fish accidentally caught-using a bigger mesh size means smaller, unwanted fish aren’t caught, and younger fish can be left to breed.
• Materials decay because they’re broken down by microorganisms.
• You can work out how much biomass has been lost at each level by taking away the biomass that is available at that level from the biomass that was available at the previous level.
• Farmers and gardeners try to provide the ideal conditions for quick decay to make compost.
• Overfishing is a threat to food security as fish stocks are declining, meaning there’s less fish to eat, food chains are disrupted and some species may disappear, so sustainable food production is needed.