Biology- unit 3 (ecosystems) Flashcards
What is a species
Group of organisms that interbreed to produce fertile offspring
What is biodiversity
The variety of organisms on earth
What is population
Number of particular species
- SAME species
What is a producer
Green plant
Photosynthesises to make food
What are consumers
Eat other plants or animals for energy
What is a carnivore
Eats animals
What is a herbivore
Eats plants
Omnivore ?
Eats both plants and animals
Predator ?
Hunts for animals for food
Prey?
Is hunted for food
What is a food chain
Shows feeding relationships and energy flow
What is a ecosystem
Consists of all the organisms living in a particular area and the non-living components which the organisms interact
What is a habitat
Where an organism lives
Community?
All the plants and animals in the ecosystem
What is a niche
The role that an organism plays within a community
What is competition
When resources are in short supply
Intraspecific competition?
SAME SPECIES
ALL RESOURCES REQUIRED
Interspacific competition
DIFFERENT SPECIES
ONE OR FEW RESOURCES
List examples of biotic factors
Competition
Disease
Grazing
Predation
List abiotic factors
Light intensity
Soil moisture
pH
Temperature
List two ways to sample plants or animals and say how they are suitable
Quadrats- growing plants and slow moving insects
Pitfall traps - small surface dwelling intervertebrates
What is an indicator species
Species that indicate environmental levels of pollution
Write the word equation for photosynthesis
Carbon dioxide + water ââ-> sugar + oxygen
Light energy
Name the 2 stages
Light reaction
Carbon fixation
Describe the steps of stage 1
Light energy trapped by chlorophyll in the chloroplasts
Converted into chemical energy - to generate ATP [used in stage 2]
Water is then split to produce hydrogen and oxygen [ oxygen diffuses from cell]
Describe stage 2
Enzyme controlled reaction
Uses hydrogen and ATP with carbon dioxide to produce sugar - glucose
What does the plant do with the sugar
Available for respiration
Starch (storage)
Cellulose (structural)
What are limiting factors
Anything that when in short supply can limit/reduce the rate of reaction
List the limiting factors in photosynthesis
Temperature
Light intensity
Carbon dioxide concentration
What do fertilisers provide
Nitrates
What is a fertiliser
Add extra nutrients to soil to increase crop yields
Name negative impacts of fertilisers
Bacteria uses up large amounts of oxygen
Can leach into water - adding unwanted and extra nitrates
What is a pesticide
Chemicals sprayed on crops to prevent damage from pests
Animals and plants can be killed
What are nitrates used for
Produce amino acids which are synthesised into plant proteins
What is a mutation
A random change to genetic material
What environmental factors can increase the rate of mutation.
Radiation and chemicals
Describe mutations
Spontaneous and the only source of new alleles
What does variation do within a population
Make it possible to evolve overtime
What is natural selection
Species produce more offspring than a environment can sustain
The best adapted individuals will survive to reproduce- eg moths
What can variation and adaptation result in
Plants and animals becoming better adapted to their environment
What does variation in a population make possible
Population to evolve overtime
What is adaptation
A characteristic that makes an organism well suited to survival in its environment
What is speciation
When part of a population becomes isolated by a barrier
What will an isolation barrier prevent
Organisms reproducing and sharing genes
Give 2 geographical examples
River
Mountains
Give 2 ecological examples
pH
Temperature
What does a sub-population do
Evolve until they become so genetically different that they are two different species - no longer reproduce
