1. study of various relationships between living organisms and their enviroment
1.1. group of organisms of the same kind = population
1.2. different populations living in same habitat = community
2. biotic environment
2.1. predator-prey relationship
2.1.1. predator = animal that kills and eats other animals
2.1.2. prey = animal that is killed and eaten by other animals
2.2. parasitism
2.2.1. a relationship between a parasite and a host & the parasite usually benefits from the host
2.3. mutualism
2.3.1. a relationship between two organisms & both benefit from it
3. ecosystems
3.1. consists of communities of organisms interacting with one another & their physical environment
3.2. living organisms can be classified under
3.2.1. producers
3.2.1.1. green plants that manufacture food substances from simple nutrients such as carbon dioxide & water.
3.2.2. consumers
3.2.2.1. animals that obtain energy and nutrients from other organisms they feed on. there are 3 types of consumers,
3.2.2.1.1. primary consumers
3.2.2.1.2. secondary consumers
3.2.2.1.3. tertiary consumers
3.2.3. decomposers
3.2.3.1. fungi & bacteria that break down the complex nutrients in excreta & dead bodies of organisms
3.3. some types of ecosystems
3.3.1. tropical rainforests
3.3.2. grasslands
3.3.3. mountains
3.3.4. deserts
3.3.5. sea shores
3.3.6. earth = biosphere
3.4. transfer of energy in a ecosystem
3.4.1. food chains and food webs
3.4.1.1. a series of organisms through which energy & food are transferred from one organism to another
3.4.1.1.1. eg. tree ➞ aphid ➞ ladybird ➞ small bird
4. pH level
4.1. most organisms cannot survive in environments that are too acidic or have too much alkaline
5. the physical environment (non-living)
5.1. depends on an organism's habitat (place they live)
6. water
6.1. * every organism needs water to survive *
6.2. amount of water in a place depends on amount of rainfall throughout the year
7. mineral salts & salinity
7.1. mineral salts are important in the manufacture of many important substances such as
7.1.1. proteins
7.1.2. vitamins
7.1.3. chlorophyll
7.2. lack of mineral salts in animals affects the growth of animals & plants
7.2.1. animals obtain them from food they eat
7.2.2. plants obtain them from soil solution
7.3. amount of salt present in water is important for aquatic organisms
7.3.1. some organisms live in very salty water (sea) while others in freshwater ponds
8. air
8.1. plants need carbon dioxide for photosynthesis
8.2. most organisms need oxygen for respiration
8.2.1. land organisms
8.2.1.1. take in oxygen from air
8.2.2. aquatic organisms
8.2.2.1. take in dissolved oxygen in water
8.2.2.1.1. polluted water = less dissolved oxygen
8.2.2.1.2. fresh, clean water = more dissolved oxygen
9. temperature
9.1. affects activities of all living oganisms
9.2. most plants & animals can survive between 0 to 45 degrees celsius
9.3. to survive under more extreme temperatures, organisms must have
9.3.1. special adaptive features or behaviours
10. light
10.1. needed for plants to make food
10.2. some animals require this to see in order to
10.2.1. move around
10.2.2. find food
10.2.3. avoid danger
10.3. some animals are sensitive to it
10.3.1. eg. owls or earthworms