ecology Flashcards
define ecology:
the study of ecosystems, and how/why they change.
what is a habitat?
the environment in which an organism lives.
what is a population?
the total number of organisms of the same species living in the same geographical area.
what is a community?
the populations of all of the different species that live in the same habitat.
what do the words biotic and abiotic mean, and give examples of each:
living (animals, plants) and non-living (soil, climate, water, minerals).
what is an ecosystem?
the biotic and abiotic parts of an environment, and how they interact.
what resources do plants compete with each other for, in order to stay alive?
plants compete with each other for light, space, water and mineral ions in the soil.
what resources do animals compete with each other for, in order to stay alive?
animals compete with each other for food, water, mating partners and territory.
why is competition important?
in the long run, it can increase species diversity, by acting as a force for specialisation and divergence.
what is interdependence?
the idea that all different species in a community depend on each other. e.g. for food, shelter.
- therefore if a species would disappear from a community, it could affect the entire community.
what is a stable community?
a community in which the populations of organisms are in balance with each other, and with the abiotic resources (e.g. water).
- in these communities, the numbers of predators and prey fall and rise in cycles.
what are the four different biotic factors, and explain them:
- food availability: all sources of food, which are relied on by animals, whether animals or plants, are a biotic factor. if the availability of food falls, the number of organisms in the community will also fall.
- predators: could cause the population of a prey species to fall. can also affect existing predators (e.g. when competing for the same prey).
- interspecies competition: if a species is outcompeted then its population can fall so much that numbers are no longer sufficient to breed and the species becomes extinct.
- new pathogens: if an infectious disease emerges and then spreads, it can wipe out a population of a species.
describe light intensity as an abiotic factor:
- can majorly affect plants.
- all plants need light to carry out photosynthesis.
- if the light intensity is too low, the rate of photosynthesis falls and plants will grow more slowly.
- therefore, animals which feed on these plants may not have enough food.
describe temperature as an abiotic factor:
- if the temperature of an environment changes, then this could cause the distribution of species to change.
- e.g. animals might migrate, and plant species would simply disappear.
describe water as an abiotic factor:
- both plants and animals require water to survive.
- without water, their populations would decrease massively.
describe pH and mineral content of soil as an abiotic factor:
- important abiotic factor for plants.
- many plants can’t grow on soil which is too acidic or alkaline.
- plants also need certain minerals in the soil, such as nitrate ions, which are used to make amino acids for proteins.
describe wind intensity and direction as an abiotic factor:
- an important factor for plants.
- strong winds blowing inland from the sea can cause plants to lose water, which is essential to their growth and development.
describe carbon dioxide and oxygen supply as an abiotic factor:
- carbon dioxide is needed for plants to photosynthesise, and if carbon dioxide levels fall, then the rate of photosynthesis also decreases.
- oxygen is needed for aerobic respiration. oxygen levels in the air are fairly constant, but oxygen levels in the water can fall, especially on hot days. this can be harmful to aquatic organisms.
to recap, what are the seven abiotic factors?
light intensity, temperature, water, soil pH, soil mineral content, wind intensity and direction, and carbon dioxide and oxygen supply.
what is the difference between quantitative and qualitative data?
- quantitative data gives a specific measure (e.g. there are 502 daisies).
- qualitative data gives a rough idea (e.g. there are lots of daisies).
what factors can affect the abundance of a plant in a field?
- light intensity
- the presence of other organisms (e.g. humans)
- natural chemicals
- soil fertility
define competition:
animals and plants have to compete for limited resources. the best adapted species will win and survive.
what is the difference between interspecific and intraspecific competition?
interspecific: competition between animals of different species.
intraspecific: competition between animals of the same species.