Life on earth Flashcards
abiotic factors
non-living factors present in an ecosystem such as temperature, soil moisture, light intensity and pH
abundance
the quantity of species in an area
acclimatise
adjust or become accustomed to new surroundings- for example when using a choice chamber it is important to allow time for the organism to acclimatise before recording results
adaptation
is an inherited characteristic (physical, physiological r behavioural) of an organism which enables it to survive successfully in its habitat
advantageous mutation
a random change to an organism’s genetic material that is beneficial and increases the organism’s chance of success
algal bloom
rapid growth of algae (simple, aquatic plants) in water
allege
each of two or more alternative forms of a gene that arise by mutation
ATP (Adenosine triphosphate)
adenosine molecule with three phosphate groups attached which can release energy when one phosphate group is removed
atypical
unusual results- usually the result of not taking enough samples, for example when throwing quadrats
bioaccumulation
the build-up of toxic substances in living organisms
biodiversity
total variation in an ecosystem including the variety that exists within a species and between different species
biological control
the control of a pest by the introduction of a natural enemy or predator
biotic factors
factors affecting a species that are directly related to, or are the result of, activities of living things
by-product
a substance made when another substance is being produced e.g. oxygen is a by-product of photosynthesis
carbohydrate
a molecule made of carbon, hydrogen and oxygen e.g. glucose, starch, cellulose
carbon fixation
the second stage of photosynthesis in which ATP, hydrogen and carbon dioxide are used to produce glucose (and oxygen)
carnivore
organism which only eats other consumers
cellulose
structural carbohydrate of which plant cell walls are composed
chlorophyll
green pigment in chloroplasts that absorb light energy for the process of photosynthesis
chloroplast
organelle containing chlorophyll; the site of photosynthesis
community
all the populations of all species in a habitat
competition
when two organisms require the same resource and that resource is in short supply
consumer
an organism that eats other organisms
DDT
example of pesticide which can build up in the body f pests. its concentration increases as it is passed along the food chain leading to lethal concentrations in top predators
decomposers
organisms (mainly bacteria fungi) which obtain energy by decomposing (breaking down) waste materials
disadvantageous mutation
a random change to an organism’s genetic material that us harmful and decreases the organism’s chance of success
distribution
the way in which something is spread over an area
ecosystem
( ecosystem = community + habitat). a natural unit made up of one or more habitats and the community or communities of plants and animals there
energy flow
the transfer of energy through food chain
environment
the sum total of all surroundings of a living organism
evolution
the change in genetic makeup of a population over successive generations, which may be caused by natural selection
fauna
animal life
fertiliser
a chemical or natural substance, containing nitrogen that is added to soil to increase crop yield
food chain
diagram which shows how energy is passed from organism to organism
food web
a network of food chains
glucose (C6H12O6)
simple sugar used as the respiratory substrate in respiration and produced by photosynthesis
GM crops
genetically modified plants which have had foreign genes (genes from other plants or animals) inserted into their genetic codes by genetic engineering to improve their characteristics
grazing
when animals eat green plant material where only part of the (plant) structure is removed e.g. horse/cow/sheep eating grass
habitat
the place where organisms live
herbivore
organism which only eats plants
humidity
the quantity of water vapour present
indicator species
species that by their presence or absence or abundance indicate environmental quantity/ levels of pollution in an ecosystem
interbreed
to sexually reproduce
interspecific competition
occurs between organisms of different species competing for the same resource (which has limited supply)
intraspecific competition
occurs between organisms of the same species competing for the same resource (which has a limited supply)
leaching
when fertilisers are washed out of the soil by rainwater
light intensity
a measurement of the brightness of light
light meter
an instrument used to measure light intensity
light reactions
first stage of photosynthesis (also known as photolysis) which needs light to occur. water is split into hydrogen and oxygen during this stage
limiting factor
a variable that, when in short supply, can limit the rate of a chemical reaction
moisture meter
an instrument used to measure the level of moisture
mutagenic agent
are things (such as radiation) which can increase the frequency of mutations
natural selection
a process where organisms possessing certain characteristics that make them better suited to a environment are selected and survive to reproduce. therefore, they pass on their advantageous characteristics to their offspring
neutral mutation
a random change to an organism’s genetic material that does not affect the survival of an organism
niche
the niche of a species is its role in its habitat
nitrate
nitrogen compounds which are taken by plants
omnivore
organism which consumes both plants and animals (to obtain energy)
paired key
a set of statements which cane be used to identify an organism
pesticides
a chemical used to kill pests (organisms-insects/animals/plants- which damage crops)
pitfall trap
a device used to trap invertebrates which are active on the ground surface
pollution
the introduction into the environment of a substance which has harmful or poisonous effects. it can affect the air, fresh water, sea and land.
population
the total number of living things of one species living in a a habitat
predation
when one organism (predator) hunts and eats another (prey) as food
predator
organisms which hunts and eats another animal
prey
organisms which is hunted and eaten by predators
producer
organisms which produce their own food (usually green plants by photosynthesis)
protein
compound containing carbon, hydrogen, oxygen and nitrogen which are an essential part of living organisms
