Genetics and Variation - Competition and Succession Flashcards
what are examples of abiotic factors?
temperature - can denature enzymes
light - source of energy for most ecosystems
pH - affects enzyme action
water + humidity - affects transpiration rates
what are some examples of biotic factors?
competition
predators
parasites and disease
what is competition?
striving to win or gain something by establishing superiority over others
when does competition occur?
when the niche of any two species overlaps
what are the 2 types of competition?
intraspecific and interspecific
what is intraspecific competition?
competition between organisms of the same species
how does variation affect intraspecific competition?
variation in the population means that some organisms can compete better than others
what is interspecific competition?
competition between different species
when does interspecific competition occur?
when individuals of different species occupy the same niche
what will happen during interspecific competition?
one species will have a competitive advantage over the other, so that population will grow while the other shrinks
what is the competitive exclusion principle?
where populations of 2 species initially occupy the same niche, one will normally have the competitive advantage
what is predation?
the preying of one animal on others
what are the stages of the predator-prey cycle?
- predators eat prey so population of prey decreases
- fewer prey alive to predators in greater competition with each other
- predator population reduced as some cannot catch enough prey to survive or reproduce
- fewer predators alive so less prey eaten so more survive and reproduce
- population of prey increases
- with more prey available, predator population increases
what is succession?
the process by which an ecosystem changes over time
what are the 2 types of succession?
primary and secondary
when does primary succession occur?
on land that is inhospitible or newly formed with no organic material
what is a pioneer species?
the first species to colonise an area
what features do pioneer species usually have?
asexual reproduction
production of seeds/spores
photosynthesis
tolerance to extremes
what is the climax community?
an ecosystem that remains stable and supports the largest and most complex community of animals and plants as it can
what are the stages of primary succession?
- pioneer species colonise area
- they die and microorganisms decompose the dead organic material forming a basic soil
- conditions less hostile as basic soil can retain water so more species move in
- organisms that are better adapted outcompete previous species
- climax community reached
when does secondary succession occur?
when land has been altered in some way eg fire, disease, grazing, agriculture
what is the main difference between primary and secondary succession?
there’s already a soil layer for secondary succession so it starts at a later stage than primary
what is conservation?
the management of the Earth’s natural resources by humans in such a way that maximum use of them can be made in the future
what are the reasons for conservation?
personal - maintains our planet
ethical - other species were here before us
economic - there is a huge gene pool with capacity to make millions of useful substances
cultural + aesthetic - enrich our nature
why is succession managed?
because in the climax community, species that were present in earlier stages of succession will have often died out due to habitat disappearing or being outcompeted
