Year 9 Science - Ecology

//included: week 1 content

biosphere

(ecosphere) made up of parts of Earth where life exists, extends to upper area of atmosphere and to deepest parts of the ocean (hydrosphere). characterised by continuous cycling of matter.

ecosystem

includes all living (biotic) things (plants, animals, organism) in given area, interacting with each other and also with their non-living (abiotic) environments (weather, earth, sun, soil, climate, atmosphere)

ecology

study of ecosystems

habitat

type of natural environment where a particular organism lives and has is needs met in order to survive and reproduce

community

group of populations of two or more different species occupying same geographical area in a particular time, consists of species that interact with each other and their environment

population

group of organisms of same species that live in a particular place in particular time, interact with each other and environment

ecosystem ecology

cycling of energy and matter

biome

distinct biological community that is formed in response to shared physical climate
5 major biomes in Australia - desert, forest, grasslands, aquatic, tundra

desert biome

- 20% of total land cover on earth
- high temperatures - little vegetative cover
- less cloud cover, low atmospheric moisture and land's exposure to sun
- humidity is low, few events of very little rain in a year

tundra biome

- 20% of total land cover on earth
- coldest of all terrestrial biomes
- least biodiversity capacity
- types - alpine tundra, arctic tundra

aquatic biome

- 73% of total land cover on earth
- life forms depend on abiotic factors - sunlight entering waters, temperature pressure, salt content etc.
- important as is home to millions of water animals, form basis of water cycle, help atmospheric moisture, cloud formation and preciptation
- types - freshwater and marine aquatic

grassland biome

- massive areas dominated by one or few species of grass, sparsely distributed tress
- tress prevented from growing because of rainfall, soil and/or human activity
- thin layer of soil -> don't hold water
- rainfall is moderate -> don't cause floods
- types - savannah and temperate grasslands

forest biome

- 30% of total land cover on earth
- store of carbon, play important role in climate control
- high temperatures throughout year, high humidity throughout year
- most biodiversity

environment

- includes all natural materials and living and non-living factors organisms can interact with

environment vs habitat

habitat - defined place/area of environment according to requirements of particular life form
- a habitat is always an environment (not vice versa)
- environment governs habitat (not vice versa)

abiotic factors

- non-living chemical or physical components of the environment
- includes climatic, soil, water and land factors

biotic factors

- living components of the environment
- impact on organism's survival or ability to reproduce
- e.g. predator-prey, infection by disease causing organisms, competition for mates

interactions in ecosystem

- relationships between organisms, interact with each other
- includes competition, predation, symbiosis

interactions in ecosystem - competition

interaction between organisms of same population/species in which chance of survival of one is affected by presence of another
- usually compete for limited resources (e.g. food, water, shelter, mates)
- one of many interacting biotic and abiotic factors that affect community structure

interactions in ecosystem - predation

- animal predated upon by another larger animals as source of energy for survival

interactions in ecosystem - symbiosis

- association between two species of organisms resulting in at least one of them benefiting from other, other species is harmed or unaffected
- includes commensalism, mutualism and parasitism

symbiosis - commensalism

one organism benefits, other is unaffected

symbiosis - mutualism

both organisms benefit from each other

symbiosis - parasitism

one organism benefits at expense of other (host), host is harmed

biodiversity

- blend of biological (life) and diversity (variety)
- variability of life on earth
- measures genetic, species, ecosystem level

adaptation

characteristics (adaptations) of an organism that help them to survive and reproduce in their natural habitat

structural adaptation

- features of an organism’s physical construction that help it to survive
- e.g. the long neck of a giraffe which enables it to eat the leaves of tall trees

behaviour adaptation

- deliberate actions of organism which help it to survive
- e.g. desert hopping mouse sleeps during the heat of the day and feeds when it is cooler

physiological/functional

- unconscious ways in which organism’s body works to help it to survive
- e.g. dogs pant to cool down body temperature

population dynamics

study of the changes in population numbers within ecosystems

population size

- number of individual organisms in population
- factors: bushfire, weather conditions, drought, severe storm and flooding, food supply, habitat limitation, earthquakes and volcanic eruptions

population density

- number of organisms per one unit area
- factors: birth rate (natality), death rate (mortality), immigration, emigration