1. pH level
1.1. most organisms cannot survive in environments that are too acidic or have too much alkaline
2. the physical environment (non-living)
2.1. depends on an organism's habitat (place they live)
3. water
3.1. * every organism needs water to survive *
3.2. amount of water in a place depends on amount of rainfall throughout the year
4. mineral salts & salinity
4.1. mineral salts are important in the manufacture of many important substances such as
4.1.1. proteins
4.1.2. vitamins
4.1.3. chlorophyll
4.2. lack of mineral salts in animals affects the growth of animals & plants
4.2.1. animals obtain them from food they eat
4.2.2. plants obtain them from soil solution
4.3. amount of salt present in water is important for aquatic organisms
4.3.1. some organisms live in very salty water (sea) while others in freshwater ponds
5. air
5.1. plants need carbon dioxide for photosynthesis
5.2. most organisms need oxygen for respiration
5.2.1. land organisms
5.2.1.1. take in oxygen from air
5.2.2. aquatic organisms
5.2.2.1. take in dissolved oxygen in water
5.2.2.1.1. polluted water = less dissolved oxygen
5.2.2.1.2. fresh, clean water = more dissolved oxygen
6. temperature
6.1. affects activities of all living oganisms
6.2. most plants & animals can survive between 0 to 45 degrees celsius
6.3. to survive under more extreme temperatures, organisms must have
6.3.1. special adaptive features or behaviours
7. light
7.1. needed for plants to make food
7.2. some animals require this to see in order to
7.2.1. move around
7.2.2. find food
7.2.3. avoid danger
7.3. some animals are sensitive to it
7.3.1. eg. owls or earthworms
8. the biotic environment (living)
9. study of various relationships between living organisms and their enviroment
9.1. group of organisms of the same kind = population
9.2. different populations living in same habitat = community
10. biotic environment
10.1. predator-prey relationship
10.1.1. predator = animal that kills and eats other animals
10.1.2. prey = animal that is killed and eaten by other animals
10.2. parasitism
10.2.1. a relationship between a parasite and a host & the parasite usually benefits from the host
10.3. mutualism
10.3.1. a relationship between two organisms & both benefit from it
11. ecosystems
11.1. consists of communities of organisms interacting with one another & their physical environment
11.2. living organisms can be classified under
11.2.1. producers
11.2.1.1. green plants that manufacture food substances from simple nutrients such as carbon dioxide & water.
11.2.2. consumers
11.2.2.1. animals that obtain energy and nutrients from other organisms they feed on. there are 3 types of consumers,
11.2.2.1.1. primary consumers
11.2.2.1.2. secondary consumers
11.2.2.1.3. tertiary consumers
11.2.3. decomposers
11.2.3.1. fungi & bacteria that break down the complex nutrients in excreta & dead bodies of organisms
11.3. some types of ecosystems
11.3.1. tropical rainforests
11.3.2. grasslands
11.3.3. mountains
11.3.4. deserts
11.3.5. sea shores
11.3.6. earth = biosphere
11.4. transfer of energy in a ecosystem
11.4.1. food chains and food webs
11.4.1.1. a series of organisms through which energy & food are transferred from one organism to another
11.4.1.1.1. eg. tree ➞ aphid ➞ ladybird ➞ small bird