ecology

• The Sun is a source of energy that passes through ecosystems
• Materials including carbon and water are continually recycled by the living world, being released through respiration of animals, plants and decomposing microorganisms and taken up by plants in photosynthesis.
• a population is the total number of organisms of a species in a habitat at a given time
• a community is the populations of all of the different species that live in the same habitat
• biotic = living
• abiotic = not living
• an ecosystem is both the biotic and abiotic parts of an environment and how they react
• plants compete with eachother for light and space
• plants also compete for water and mineral ions in the soil
• animals compete with eachother for food and water and mating partners and territory
• all of the different species in a community depend on each other, scientists call this interdependence
• in most communities the populations of different species remain constant, scientists call this a stable community
• in a stable community the population of organisms are in balance with each other and with the abiotic resources for example water
• there are 4 different biotic factors: availability of food, arrival of a new predator, competition between species, new pathogens
• there are 7 different abiotic factors: light intensity, temperature, water, ph and mineral content of the soil, wind intensity and direction, carbon dioxide and oxygen
• structural adaptations are adaptations of body shape of body structure.
• functional adaptations are adaptations to the body functions of an organism
• behavioural adaptations are adaptations to the animals lifestyle or behaviour
• organisms which are adapted to live in extreme conditions are called extremophiles
• every food chain starts with a producer
• producers synthesise complex molecules (green plants make the molecule glucose by photosynthesis)
• scientists call molecules such as glucose, biomass
• biomass molecules now pass down the food chain to other organisms
• the producers are the source of all the biomass in a community
• organisms that eat the producer are called primary consumers
• animals that eat the primary consumers are called secondary consumers
• the animal that eats the secondary consumer is called the tertiary consumer
• consumers that kill and eat other animals are called predators
• the animal that is being killed and eaten by another animal is called the prey
• random sampling is used to compare the number of organisms in different areas, to do this we use a quadrat.
• a quadrat is a square
• to use a quadrat we place it on the ground and count the number of organisms in the square
• total population size = (total area/area sampled) x number of organisms of that species counted in sample
• sampling along a transect is used to determine whether the number of species change as we move across a habitat.
• a transect is a line such as a rope and we place the transect so it runs across the habitat that we are looking at. we then use a quadrat to count the number of organisms at intervals along the transect.
• the carbon cycle starts with carbon dioxide in the atmosphere, carbon enters the carbon cycle through photosynthesis where it is made into glucose, carbon is released back into the atmosphere via aerobic respiration
• Carbon dioxide in the atmosphere is a product of photosynthesis, which adds carbon to plants and algae, where it is used to make carbohydrates, fats and proteins that make up the cells of plants and algae.
• Carbon can go 2 ways after it is used in photosynthesis: it can be returned to the atmosphere via respiration, the plant can be eaten by and animal and then another animal
• The carbon in plants is eaten by animals, and these animals can be eaten by other animals.
• The carbon in plants becomes part of carbohydrates, fats and proteins in the cells of animals.