Nat 5 - Unit 3 Flashcards
Food Chain
The sequence of what eats what in a community
Food Web
A network of interrelated food chains
Carnivore
An organism that eats animals
Herbivore
An organism that eats plants
Omnivore
An organism that eats plants and animals
Producer
Plants that produce chemical energy, through photosynthesis.
(to produce their own food)
Primary consumer
An organism which eats a producer
Secondary consumer
An organism which eats primary consumers
Tertiary Consumer
An organism which eats secondary consumers
Quaternary Consumer
An organism which eats tertiary consumers
Predetor
An organism which hunts its food
Prey
An organism which is hunted
Population
The number of organisms of the same species in an area
Community
The number of different species of organisms in an area
A group of interdependant organisms that contain different species
Ecosystem
All the organisms (community) living in a particular habitat and all the non-living components (abiotic factors) which affect them.
Abiotic
A Non-living factor that can affect organisms
Biotic
A living factor that can affect organisms
Species
A group of similar species that can interbreed to produce fertile offspring
Biodiversity
The variety of species in an area
Interspecific competition
occurs when when members of different species compete for the same resources.
Intraspecific competition
occurs when members of the same species compete for exactly the same resources
Why is intraspecific competition more intense than interspecific competition?
Because in intraspecific competition because the competing organisms have identical needs
What do animals compete for
food, shelter, territory, mates
What do plants compete for
Light, water, nutrients, space to grow
Consumers
Organisms which rely on eating other organisms for their food.
Mutation
A random change to genetic material: the only source of new alleles.
Natural Selection
The process by which those with favourable alleles (best adapted to the environment), survive and reproduce, passing on their genes.
Evolution
A change in the inherited characteristics of a population which overtime through a process of natural selection. Which may result in the formation of a new species.
What needs to be present in a population for evolution to occur
Variation within a population
Mutations may be..
neutral, advantageous or disadvantageous (to survival)
Types of isolating barriers
Ecological, geographical or behavioural
Environmental factors which increase the rate of mutation
Radiation and some chemicals
When does natural selection occur?
When there are selection pressures
New alleles from mutations can result in..
Plants and animals becoming better adapted to their environment
Natural Selection occurs when..
- More offspring are produced than the environment can sustain
- There are selection pressures
- Only the best adapted individuals survive to reproduce
- They pass on their favourable alleles that give the selective advantage
- These alleles increase in frequency in the population
Speciation occurs when…
- Part of the population becomes isolated by an isolation barrier
- Different mutations occur in each subpopulation
- Natural selection selects for different mutations in each group
- Due to different selection pressures
- Each sub-population evolves until their genetic differences make them two different species.
Show the sequence of antibiotic resistance in bacteria as an example of evolution
Mutation -> use of antibiotic -> natural selection
What is Speciation?
The process by which two distinct species evolve from a single original species by natural selection
Would the best organism within a species to survive and reproduce be:
a) the strongest?
b) the one which reproduces the fastest?
c) the best adapted to the environment?
c) the best adapted to the environment
Why is variation important to the survival of a population?
Because it allows the population to adapt to changing environmental conditions.
