Life On Earth Flashcards
What is an adaptation?
A feature of an organism that helps it survive eg thick, hollow fur for insulation in Polar Bears
What is an Abiotic factor?
Refers to a physical (non-living) factor that affects an ecosystem eg temperature, light intensity, pH etc
What is an algal bloom?
A rapid growth in population of algae in ponds/lakes caused by an increase in inorganic nutrients from fertilisers.
What is an allele?
A particular form of a gene.
Where is ammonia found in the Nitrogen cycle?
After death and decomposition and before nitrite.
What is bio accumulation?
Build up of toxic substance in an organism because it is hard to break down. Toxin absorb from the environment or thought food.
The definition of biodiversity.
It is the number and abundance of different species within an ecosystem.
What is a biological control?
A natural control of pests using natural predators, parasites or disease.
What is a biome and what can influence there distribution?
A biome is a region of the plant with characteristic climate, plants and animals. It is influenced by temperature and rainfall.
What is a Biotic factor?
A biological (living) factor that affects an ecosystem eg predication or competition.
What is a carnivore?
A consumer that gets its energy from eating other animals.
What is the definition of a community?
All the populations of different species living in a habitat.
What is intraspecific competition?
Competition for resources between individuals of the SAME species.
What is interspecific competition?
Competition for resources which occurs between individuals of DIFFERENT species.
What is the more severe form of competition intraspecific or interspecific?
Intraspecific because because the requirements for individuals are identical.
What is a consumer?
An organism which gets its energy by feeding on other organisms.
What is a decomposer? Name one.
A decomposer is an organism involved in the breakdown of dead organic material and waste. Examples are bacteria or fungi.
Definition of deforestation?
Large scale removal of trees from an area.
What do denitrifying bacteria do?
They convert nitrates in the soil into nitrogen gas, which is released into the atmosphere.
What is desertification?
The process by which arid land becomes desert. May be a result of climate change.
What is an ecosystem?
An ecological system consisting of a habitat and it’s community of organisms.
What is evolution?
The change in inherited characteristics of an organisms from generation to generation. It leads to gradual change in the characteristics of a species and the divergence into a new species.
What is a fertiliser?
A chemical added to soil to improve plant growth and crop yield. Contains nitrogen, potassium and phosphorus.
What is a food chain?
A linear sequence of organisms showing the feeding relationship between them. Starts with a producer and ends in the top predator.
What does Genetically Modified (GM) mean?
An organism/cell that has had its genetic code altered by the addition of a gene from another organism. Gives it a new characteristic.
What is a habitat?
An area in which a population of organisms live.
What is habitat destruction?
Human destruction of natural habitat by activities such as deforestation/over grazing.
What is a herbivore?
An animal that gets its energy by eating plants.
What is an indicator species?
Organisms (eg lichen) that by the presence, abundance or absence give information such as pollution levels in the environment
What is a monoculture?
Large scale growing of a single crop. Good economic benefits due to large yields BUT can cause soil depletion and disease.
What is a mutation?
A random or spontaneous change of a gene, chromosome or number of chromosomes. The only source of new alleles!
What is a mutagen?
Something that increase the rate of mutation. Example include UV light, radiation, x-rays, nicotine, etc
What is a niche?
The ROLE an organism has within its community in an ecosystem.
What do nitrifying bacteria do?
Convert ammonia into nitrite. Then convert nitrite into nitrate.
What does nitrogen fixing bacteria do?
Bacteria free living in the soil or root nodules of some plants that covert nitrogen gas into nitrate.
What is natural selection?
Process when variation may increase or decrease in frequency in a species because the variation affect the chance of survival of individuals that possess them.
Advantageous variations are selected due to living organisms surviving and reproducing.
What is a pesticide?
A pesticide is a chemical used to kill pests.
What is a pitfall trap?
A sampling technique used to catch ground-living invertebrates.
The definition of a population.
All the members of a single species in a given area.
What is a producer?
Green plants that produce their own food through photosynthesis. First organism in a food chain.
What is parasitism?
An interaction between 2 organisms in which one benefits and the other is harmed.
What is a pyramid of numbers?
Diagram that shows the relative numbers of organisms at each level in a food chain.
What is a pyramid of biomass?
A diagram that shows the relative total masses of the organisms at level in a food chain.
What is a pyramid of energy?
Diagram that shows the relative quantities of energy at each level in a food chain.
What is best a pyramid of numbers, biomass or energy.
A pyramid of energy gives a truer picture because it is scaled to equivalent units of area and time for each level in a food chain.
What is a quadrat and what is it used for?
A sampling tool used to measure the abundance and distribution of slow or non-moving organisms.
Definition of radiation.
An energy wave form such as light, sound, heat, x-rays, gamma rays. Can cause mutations.
What is a root nodule?
Small swelling on the roots such as peas, beans and clover that contains nitrogen fixing bacteria.
What is selection pressure?
Factors such as predication or disease that affects a population, resulting in the death of some individuals and survival of others.
What is speciation?
The formation of 2 or more species from an original ancestral species due to isolation of the 2 or more species. Leading to a point where the new species are unable to interbreed.
What is a species?
Organisms with similar characteristics and with the ability to interbreed to produce fertile offspring.
What is a transect?
A sampling technique which involves taking samples at regular intervals along a straight line. Can be used to study the effect of a variable (eg light intensity) in a given area.
