Unit 3 - Life on Earth Flashcards
The variety of life forms in a particular area. The higher it is the better
Biodiversity
Organisms which produce their own food source
Producers
Organisms which require to eat other organisms to survive
Consumer
Organism which only eats plant material
Herbivore
Organism which eats both plant and animal matter
Omnivore
Organism which only eats animals
Carnivore
Define the word:
Species
Organisms that can reproduce to have fertile offspring
The number of one species of organism in a habitat
Population
All the different species in a habitat
Community
Define the word:
Ecosystem
All the living organisms and non-living components in a particular habitat
Define the word:
Niche
The role an organism plays within a community
Intraspecific competition occurs between …
Members of the SAME species
Interspecific competition occurs between …
Members of different species
Give an example of something organisms would compete for
Sunlight (plants)
Habitat
Food
Mates
Why is intraspecific competition more intense than interspecific?
Organisms of the same species all require the exact same resources
Non-living factors that affect biodiversity.
Abtiotic factors
Examples of abiotic factors
Temperature OR Light intensity OR pH OR Oxygen concentration
Examples of biotic factors
Predation OR Grazing OR Food availability OR Disease
The place an organism lives
Habitat
A relationship between animals in which one hunts, kills and eats the other
Predation
A feeding relationship between two organisms in which one organism benefits and the host is harmed
Parasitism
Percentage of energy lost at each level of a food chain
90%
Percentage of the energy in food used for growth
10%
Ways in which energy is lost at each level in a food chain
Heat OR Movement OR Undigested food
A diagram with the width of each bar representing the number of organisms at that feeding level in a food chain
Pyramid of numbers
A diagram with the width of each bar representing the total mass of organisms at each stage of a food chain
Pyramid of biomass
A method for sampling ground living invertebrates in an area by placing concealed pits for them to fall into
Pitfall traps
A square placed on the ground before counting the plants inside
Quadrat
Ways to reduce sampling error with quadrats or pitfall traps
Place randomly
Take many samples
Reason for sampling several times with a quadrat
Increase reliability
Instruments used to measure abiotic factors
Light meter OR Moisture meter OR pH meter OR Thermometer
Helped to identify organisms
Biological keys
Their presence or absence indicate environmental quality/levels of pollution
Indicator species
Number of stages in photosynthesis
2
First stage of photosynthesis in which water is split
Photolysis
Molecule which traps light energy from the sun
Chlorophyll
Leaf organelle which contains chlorophyll and is the site of photosynthesis
Chloroplast
Energy rich molecule synthesised during the light reaction
ATP
Type of energy in ATP
Chemical energy
Required to synthesis ATP
ADP + Pi + energy
Produced when water is split
Hydrogen and Oxygen (and energy)
A by-product of water splitting that diffuses out of the leaf
Oxygen
Carries hydrogen from the first to the second stage
Hydrogen Acceptor
Second stage of photosynthesis where glucose is synthesised
Carbon fixation
Controls the series of photosynthesis reactions
Enzymes
Produced by water splitting and combines with carbon dioxide to produce glucose
Hydrogen
Molecules required to produce glucose
Hydrogen, Carbon dioxide and ATP
Product of photosynthesis that can be used in respiration or converted to other molecules
Glucose
Structural carbohydrate used to make cell walls
Cellulose
Storage carbohydrate in plants
Starch
Word equation for photosynthesis
Water + Carbon dioxide —–> Glucose + Oxygen
Term for an essential input in short supply that reduces the rate of photosynthesis
Limiting factor
Limiting factor on a cloudy day in summer
Light intensity
Limiting factor on a sunny day in winter
Temperature
Three factors that may limit the rate of photosynthesis
Light intensity & temperature & carbon dioxide concentration
Nitrate rich substances used by farmers to grow crops
Fertilisers
Chemicals use by farmers to eradicate insects and weeds
Pesticides
Process of fertilisers leaching into fresh water
Eutrophication
Define the process of eutrophication
- Fertilisers wash into rivers and lakes
- Algal blooms grow and block out light
- Plants in water die and eaten by bacteria
- Bacteria use up available oxygen in water
- Animals may die due to lack of oxygen
Technique involving gene alteration to reduce fertilisers
Genetic modification
Term given to pesticides accumulating in food chains, causing increased toxicity
Bioaccumulation
Random changes to genetic material that are the only source of new alleles
Mutation
Environmental factors that increase the rate of mutation
Radiation OR UV light OR X-rays OR Some chemicals
An inherited characteristic that makes an organism well suited to survive in its environment
Adaptation
Biological term for a group of organisms that can interbreed and produce fertile offspring
Species
Biological term for an organism best adapted to its environment surviving and passing on its favourable alleles to its offspring
Natural Selection
Biological term for an organism best adapted to its environment surviving and passing on its favourable alleles to its offspring
Natural Selection
OR
Survival of the fittest
Factors in the environment which make the survival of certain
individuals more likely than others
Selective pressures
The process by which a new species can arise as a result of the isolation of a part of a population in an environment with different selection pressures
Speciation
When part of a species is separated from the rest so that they cannot interbreed for a long period of time
Isolation
A reason for different alleles arising in two isolated sub-populations
Mutations
Biological term for the gradual change in the genetic make up of a population as a result of natural selection over many generations.
Evolution
What results when different selection pressures select for
different mutations in two isolated sub-populations over a long period
of time?
Two different species
