Interactions Within Ecosystems Flashcards
what is ecology?
study of interactions of organisms with one another, or between organisms and physical factors of the environment
what is an ecosystem?
formed when different communities of organisms interact with one another and their environment
what are communities?
all populations of organisms living and interacting with one another in a particular habitat
what are populations?
group of organisms of the same kind living together in a habitat
what are the 6 factors of the physical environment?
(amount of) light
temperature
(availability of) water
air
mineral salts and salinity
pH
how does the amount of light affect the biotic environment? (2 points)
affects rate of photosynthesis and growth in plants (some grow better in moist, shaded areas though)
amount of light available determines the kind of plants, and hence, the kind of animals found in a habitat
how does temperature affect the biotic environment? (2 points)
low temperatures slow down rate of photosynthesis and stunt plants’ growth, and slow down blood circulation in animals, making them sluggish
most plants and animals can survive 0°C to 45°C
how does the availability of water affect the biotic environment? (3 points)
all organisms need water to survive
amount of water in any place depends on the rainfall it receives
generally, more organisms found where water is available
4 points
how does air affect the biotic environment?
plants need carbon dioxide for photosynthesis
most organisms needs oxygen for respiration (land organisms from air, aquatic organisms from water)
polluted water usually contains less dissolved oxygen
many fishes cannot survive in polluted water (but some organisms have adapted to)
how do mineral salts and salinity affect the biotic environment? (4 points)
mineral salts important in production of many essential substances (e.g. proteins, vitamins, chlorophyll)
plants obtain mineral salts from soil, animals from food
salinity affects water potential of solutions
some aquatic organisms adapted to live in very salty water, others in streams/fresh water ponds
how does pH (acidity/alkalinity) affect the biotic environment? (4 points)
land plants/aquatic organisms pH-sensitive as pH affects rate of enzyme reactions
most organisms cannot survive in extreme-pH environments
freshwater organisms tolerate pH ~7, marine organisms pH ~8
pH of water varies during day as photosynthesis uses up dissolved carbon dioxide in water, making it more alkaline
what are 3 relationships in the biotic environment?
parasitism
mutualism
predator-prey relationship
what is parasitism?
relationship between 2 organisms in which 1 (parasite) benefits at the expense of the other (host)
parasite normally does some harm to host
what is mutualism?
relationship between 2 organisms with both benefitting from each other
what is a predator?
animal that lives by killing and eating other animals
what is a prey?
animal that is killed and eaten by another animal
what are producers?
organisms that make their own food by photosynthesis (not just plants), contain chlorophyll
why do producers need chlorophyll?
traps light energy to synthesise with glucose from carbon dioxide and water
what are consumers?
organisms unable to make their own food and feed on other organisms
primary consumers: feed on producers
secondary consumers: feed on primary consumers
tertiary consumers: feed on secondary consumers
what are decomposers and their use?
organisms (fungi & bacteria) that break down complex nutrients in faeces/dead organisms with the help of enzymes
return carbon dioxide into atmosphere, soluble mineral salts into soil
what are scavengers and their use?
organisms (e.g. earthworms) that feed on dead/decaying matter
help decomposers break down dead organisms into simple substances faster
what is a food chain?
sequence of organisms, each being a source of food for the next, through which energy is transferred from one organism to the next
each feeding stage: trophic level
arrows go from food to feeder (goes into the mouth of)
what is a food web?
made of inter-linked food chains
what is an ecosystem’s ultimate source of energy?
the sun
how do producers get energy?
they synthesise their own organic food molecules through photosynthesis, using light energy from the sun
how do consumers get energy?
when consumers feed on producers/other consumers, energy is transferred
how is energy lost along the food chain?
~90% of energy may be lost as heat released during respiration, passed out as undigested materials (only transferred to decomposers) and excretory waste products (e.g. urea) by consumers
total amount of energy decreases along food chain
why is the energy flow in ecosystems non-cyclical?
~90% of energy lost as heat
energy lost cannot be recycled
what are ecological pyramids?
diagrams showing relationship between producers and consumers at different trophic levels within an ecosystem
how are ecological pyramids drawn? (2 important points)
drawn using horizontal bars
producers at bottom, tertiary consumers at top
what is the use of a pyramid of numbers?
allows us to compare number of organisms in each trophic level at a particular time
how are pyramids of numbers drawn? (2 points)
length of bars represent number of organisms
each bar to be labelled with names of organisms (in bars) or trophic levels (right of bars)
what is the use of a pyramid of energy?
shows total energy at each trophic level (amount of energy decreases from one trophic level to the next)
how are pyramids of energy drawn?
drawn upright (longest bar at bottom, shortest at top) as the amount of energy decreases from one trophic level to the next
what are the differences between aerobic respiration and photosythesis? (conditions needed, energy conversions, equation)
aerobic respiration:
1) requires foods molecules (glucose), oxygen
2) chemical energy stored in food released and converted into other forms in animals, respiration occurs in all living cells
3) glucose + oxygen –> carbon dioxide + water + energy
photosynthesis:
1) requires light energy, chlorophyll, carbon dioxide, water
2) light energy converted into chemical energy and stored as complex nutrients (e.g. glucose)
3) carbon dioxide + water –(light + chlorophyll)–> glucose + oxygen
what does the cycle of nutrients involve? (types of processes and environments)
brought about by physical, chemical, and biological processes
involves both abiotic (physical) and biotic environments
(carbon is one of the many nutrients cycled in the environment)
how is carbon dioxide removed from the atmosphere? (2 points, plant and animal)
photosynthesis, carbon becomes part of glucose in plants
when consumers feed on these plants, glucose become part of their bodies
how is carbon dioxide returned into the atmosphere? (3 ways)
released during:
1) respiration of organisms
2) combustion of wood and fossil fuels
3) decomposition
why is the carbon cycle important? (2 points)
ensures continuous supply of carbon dioxide for photosynthesis
understanding carbon cycle helps us study effects of man’s activity on environment, and then taking steps to maintain equilibrium in atmosphere
what is conservation?
protecting and preserving of the environment
why reduce global warming and prevent disruption of natural cycles?
air pollution harmful to health and contributes to global warming
why and how to protect different kinds of plants and animals (including marine life)? (3 points)
water pollution threatens land/aquatic organisms that depend on water to survive
marine ecosystems protected by law in some countries as fishes make up important part of food supply
prevents over-fishing by banning drift nets, regulating fishing ships/periods, raise endangered species of fish in hatcheries
why preserve tropical rainforests?
overuse of land and deforestation leads to barren, unproductive land
tropical rainforest have sources of food and raw materials for medicinal drugs
what is sustainable living?
lifestyle that aims to meet present needs without damaging environment and depleting resources that future generations may need
how to live sustainably? (4 ways)
wind turbines
terrace farming (slows down water run-off, prevents erosion)
ban trade in animal parts
protect endangered animal species
