Populations and Environment Flashcards
What is an ‘ecosystem’?
all of the living and non-living components of a particular area
What is meant by the term ‘abiotic factors’?
an ecological factor that makes up part of the non-biological environment
What is meant by the term ‘biotic factors’?
an ecological factor that makes up part of the living environment
What is meant by the term ‘population’?
a group of individuals of the same species that occupy the same habitat at the same time
What is meant by the term ‘habitat’?
the place where an organism normally lives and which is characterised by the physical conditions and the types of organism present
What is meant by the term ‘species’?
a group of similar organisms that can breed to produce fertile offspring
What is meant by the term ‘community’?
all of the living organisms present in an ecosystem at a given time
What is meant by the term ‘niche’?
describes how an organism fits into its environment. (includes: what the species is like; how it responds; how it behaves; where it occurs)
NO 2 SPECIES CAN OCCUPY THE SAME
Give 4 things that can impact population size
- intraspecific competition
- interspecific competition
- predation
- abiotic factors (e.g, water, pH, temp.)
Give 3 things that can be competed for between different species
- water
- food (nutrients if talking about plants)
- space/territory
Give 3 things that can be competed for between organisms of the same species
- mates/breeding sites
- food
- space
- water
Why might a correlation not show the causal effect (on a graph showing time and population size)?
correlation ≠ causal effect
it could be caused by other biotic factors, such as interspecific competition.
One species could have outcompeted the other for (a specific resource)
Why does interspecific competition take longer to influence population size?
- lots more factors involved
- death and birth rates
How might an increase in intraspecific competition drive natural selection?
if caused by change in environment, may lead to one species having a selected advantage for a particular species
In relation to competition, how would less resources impact population size?
less resources (food, space, water)
means more competition
would reduce population size if the species which is outcompeted
How is temperature a limiting factor of the carrying capacity of a population?
- enzymes in plants, bacteria and reptiles will denature (no thermoregulation)
- in mammals; more energy is needed to maintain body temperature so less energy is available for growth and reproduction
What biotic factors could limit carrying capacity?
- diseases
- predation
- intra and interspecific competition
What is meant by the term ‘carrying capacity’?
the maximum stable population size of a species that an ecosystem can support
Why is the population size of predator and prey limited in stable communities?
as the numbers of prey are increasing and decreasing in cycles
Why might nutrients leaking into lakes cause fish populations to decrease?
- algal bloom blocks sunlight
- reduced photosynthesis causes plants to die
- saprobionts respire aerobically
- less oxygen for fish to respire
How might digesting other organisms allow plants to grow in places with little nutrients available?
- nutrients such as proteins can be broken down
- provides amino acids that can be used to make proteins in the plant
disease X is caused by an insect. How would introducing infertile insects reduce the transmission of disease X?
- intraspecific competition for mates, food and space
- insects do not reproduce
- fewer insects
disease X is caused by an insect. Why might introducing infertile insects NOT reduce disease X?
- impacts courtship behaviour
- affects survival
