B4 - ecosystems Flashcards
what is a habitat
a place where plants, animals and microorganisms live
what does abiotic mean
non living elements of an ecosystem such a climate, temperature, water and soil type
what is an ecosystem population
all the members of a single species that live in a particular habitat
what is an ecosystem community
all the organisms that live in a habitat (plants and animal)
what is an ecosystem
the living organisms in a particular area, together with the non living components of the environment
what does biotic mean
living elements of an ecosystem, such as plants and animals
what are some examples of biotic elements
organic matter, living things, oysters, jellyfish, zooplankton
what are some examples of abiotic elements
climate, non living things, sunlight, temperature, humidity, soil
how do you measure temperature
with a thermometer or temperature probe
what effect does temperature have on living organisms
in low temperatures, chemical reactions happen too slowly, meaning all metabolic reactions slow down
how do you measure nutrients/soil pH
chemical analysis/ indicator paper
what effect do nutrients/ soil pH have on living organisms
plants and microorganisms need nutrients to make other chemicals they need to grow
how do you measure the amount of light
with a light meter or light sensor
what effect does light have on living organisms
plants need light for photosynthesis
how do you meausure water
with a rain gauge/ dehydrate soil sample
what effect does water have on living organisms
needed by all organisms for living processes
how do you meausure oxygen
with a gas probe
what effect does oxygen have on living organisms
needed by all organisms for aerobic respiration
how do you meausure carbon dioxide
with a gas probe
what effect does carbon dioxide have on living organisms
needed by plants for photosynthesis
what is a quadrat
a square frame of know area used for sampling abundance and distribution of slow or non moving organisms
what are transects used for
transects are used to investigate changes in population from one area to another, for example down a rocky seashore or along sandunes or marshland
what is used for transects
a measuring tape or chord is marked at regular intervals is laid out across the area
how are organisms samples when using transects
organisms are sampled by placing a quadrat at regular intervals along the line
what is distribution
the spatial arrangement of a population across an area
what are the 3 different types of distribution
uniform, random, clumped
what does a pitfall trap do
traps small invertebrate animals living on soil
what does a pooter do and what is the fine mesh used for
collects insects
the fine mesh is used to prevent inhalation of organisms in the container by the user
what does a tullgren funnel do
collects insects
how is a pooter used
1) insects are pulled into the container through a metal tube
2) inhale through the flexible tube
what is a tullgren funnel
an apparatus for collecting small organisms from soil or leaf litter
what is a net (kick sampling) used for
used to sample invertebrates living on the bottom of flowing water, using a net to capture organisms which can then be identified
what are decomposers
organisms that gain their energy by feeding on dead or decaying material
what is a detritivore
a small animal which breaks down organic matter into small pieces. they can help speed up decomposition
what are some examples of decomposers
bacteria, fungi, snails, some insects
how is temperature a factor affecting rate of decomposition
too high - denatured enzymes.
prevents decomposition.
death of microorganism.
how is water content a factor affecting rate of decomposition
little water would slow down reactions
reduces/stops decomposition
how is oxygen availability a factor affecting rate of decomposition
oxygen needed for respiration.
anaerobic conditions prevent most decomposition.
microorganisms cannot survive in anaerobic conditions
what is the equation to calculate the rate of decay
rate of decay (g/day) = change in mass (g) ÷ time (day)
what is the water cycle
the continuous journey water takes from the sea, to the sky, to the land and back to the sea
why is the water cycle important
because it ensures the availability or water for all living organisms, and regulates weather patterns on our planet
what is transpiration
the loss of water from a plant. transpiration is caused by the evaporation and diffusion of water from a plant’s surface. most transpiration happens at the leaves
what is evaporation
the process where liquid changes to a gas
what is condesation
the process where gas changes to a liquid
what is precipitaion
any form of moisture that falls to the ground. this includes rain, snow, hail and sleet. precipitaion occurs when water vapour cools
what are some key facts about carbon
the atmosphere contains 0.04% of carbon.
carbon is a material in photosynthesis.
animals eat plabts, therefore absorbing carbon
how is carbon dioxide returned to the atmosphere
by plants, animals and decomposers respiring.
by combustion of fossil fuels and wood.
by volcanoes as they release carbon dioxide from the earth’s core into the atmosphere
what is the process of the carbon cycle
1) photosynthesis and eating of plants
2) death of plants and animals and excretion
3) respiration
4) decay and respiration
5) combustion
what are some key facts about nitrogen
atmospher contains 78.09% nitrogen (also in soil).
plants take in nitrogen and store it.
animals need it for proteins.
bacteria can decompose plants and animlas
what is the role of decomposers
to return the nitrates in plants and animals to the soil
how do decomposers return nitrates in plants/animals to the soil
1) when plants and animals die and decay, decomposers break their proteins down, releasing ammonia
2) animal wastes, urea and faeces, contain nitrogen. they convert it to ammonia
what is the role of denitrifying bacteria
are in the soil and break down nitrates, releasing nitrogen into the air
what is the role of nitrogen fixing bacteria
convert nitrogen gas into a useable form by the plants
what is the role of nitrifying bacteria
convert the ammonia (in urine) to nitrates
why must nitrogen in the air be turned into
nitrogen in the air must be turned into a form that plants can use by nitrogen fixation
what does lightning do in the nitrogen cycle
lightning fixes nitrogen in the air and turns it into nitrates in the soil
what is decomposition
the process by which dead animals and plants are turned into nitrates by putrefying bacteria
how are ammonia compounds turned into nitrates
ammonia compounds are turned into nitrates by nirtifying bacteria
what are producers
plants that begin the food chain by making energy from carbon dioxide and water
what is the role of primary consumers
eat producers for example plants and algae
what is the role of secondary consumers
eat the primary consumers to obtain energy
what are omnivores
animals that eat plants and animals
what is an example of a food chain
sun-grass-grasshopper-shrew-owl
what does energy do in a food chain
energy moves through (along) food chain
what do trophic levels describe
trophic levels describe the feeding positions in the food chains. energy is transferred from one trophic level to the next, along the food chain
what does parasitism mean
when one organism benefits but the other is harmed by the relationship
what does mutusalism mean
where 2 organisms of different species exist in a relationship, where each species benefits from the activity of the other
what does predatation mean
a biological interaction where a predator (an organism that is hunting) feeds on prey (the organism that is attacked)
what are the 3 different stages of decomposers releasing nutrients
1) enzymes released by fungus
2) enzymes digest the dead matter and make it soluble
3) soluble products absorbed by the fungus
Why aren’t food chains long
Energy is lost at all levels in food chains
Animals at the top of a long food chain would not have enough energy to survive
What does the area of each bar represents in a pyramid of numbers
The number of organisms at each trophic level in a specified area
What does the area of each bar represent in a pyramid of biomass
The amount of organic matter,biomass, at each trophic level in a specified area
What happens at each trophic level in a pyramid of biomass
At each trophic level the amount of biomass and every available is reduced, giving a pyramid shape
What are 4 disadvantages of pyramids of biomass
1) organisms need to be collected and killed to measure dry mass
2) it is difficult to catch and weigh the organisms
3) biomass varies
4) some organisms are omnivores and feed at more than one level
Why is biomass lost
Some plant material, which cannot be digested, leaves the body as faeces.
Some animal material cannot be digested e.g. bone,horn, hooves, claws and teeth.
Biomass eaten by animals is also used in respiration to release energy, and leaves the animal as carbon dioxide and water
What is the equation for energy efficiency
Efficiency of energy transfer =
(Energy transferred to next level (output) ÷ energy in the previous level (input)) X 100
