TOPIC 7C - POPULATIONS IN ECOSYSTEMS Flashcards
Give the definition of a habitat.
The place where an organism lives.
e.g. a rocky shore or a field
Give the definition of a population.
All the organisms of one species in a habitat.
Give the definition of a community.
Populations of different species in a habitat make up a community.
Give the definition of an ecosystem.
A community, plus all the non-living (abiotic) conditions in the area in which it lives. Ecosystems can be small, e.g. a pong, or large, e.g. an entire ocean.
Give the definition of abiotic conditions.
The non-living features of the ecosystem.
e.g. temperature and availability of water.
Abiotic factors include the amount of light, water or space available, the temperature of the surroundings or the chemical composition of the surroundings. When abiotic conditions are ideal for a species, organisms can grow fast and reproduce successfully.
Give the definition of biotic conditions.
The living features of the ecosystem.
e.g. the presence of predators or food.
Give the definition of a niche.
The role of a species within its habitat.
e.g. what it eats, where and when it feeds.
Give the definition of an adaptation.
A feature that members of a species have that increases their chance of survival and reproduction,
e.g. giraffes have long necks to help them reach vegetation that’s high up. This increases their chances of survival when food is scarce.
Explain a niche and give two examples of one.
(see page 170 in the revision guide)
What are physiological adaptations?
Processes inside the organism’s body.
What are behavioural adaptations?
The way an organism acts.
What are anatomical adaptations?
Structural features of the organism’s body.
What is natural selection?
Organisms with better adaptions are more likely to survive, reproduce and pass on the alleles for their adaptations, so the adaptations become more common in the population.
Give 3 examples of organisms that have adapted to abiotic conditions.
(see page 171 in the revision guide)
Give 3 examples of organisms that have adapted to biotic conditions.
(see page 171 in the revision guide)
Give the definition of population size.
The total number of organisms of one species in a habitat.
Give the definition of carrying capacity.
The maximum stable population size of a species that an ecosystem can support.
Carrying capacity varies as a result of both abiotic and biotic factors.
How does the ideal temperature of a mammals surroundings affect their population size?
When the temperature of a mammal’s surroundings is the ideal temperature for metabolic reactions to take place, they don’t have to use up as much energy painting their body temperature. This means more energy can be used for growth and reproduction, so their population size will increase.
How does the temperature when its not ideal of a mammals surroundings affect their population size?
When the temperature os a mammals surroundings is significantly lower or higher than their optimum body temperature, they have to use a lot of energy to maintain the right body temperature. This means less energy will be available for growth and reproduction, so their population size will decrease.
What is interspecific competition?
When organisms of different species compete with each other for the same resourced.
e.g. red and grey squirrels compete for the same food sources and habitats in the UK.
In interspecific competition, what happens to the population size of both species competing?
Decrease.
or
If one is better adapted, the other will be out-competed.
(see page 172 in the revision guide)
What is intraspecific competition?
When organisms of the same species compete with each other for the same resources.
(see page 172 in the revision guide)
How are predator and prey population sizes linked?
(see page 173 in the revision guide)
What is predation?
Where an organism (the predator) kills and eats another organism (the prey)
e.g. lions kill and eat (predate on) buffalo.
