YR9 core questions-ecology and genetics Flashcards
(40 cards)
What are the levels of organisation of an ecosystem?
Individual organism, population, community, ecosystem
What is a population?
A group of individuals of the same species living together
What is a community?
All the living organisms in a habitat
What is an ecosystem?
The interaction of a community with the non-living parts of their environment
What is an abiotic factor?
A non-living factor affecting a community
Give seven examples of abiotic factors
Light intensity, temperature, moisture levels, soil pH, wind strength/direction, carbon dioxide levels (plants), oxygen levels (aquatic animals)
What is a biotic factor?
A living factor affecting a community
Give four examples of biotic factors
Food availability, new predators, new pathogens, competition between species
What is interdependence?
Each species in a community depends on another for survival
Give four examples of interdependence
One species depends on another for food, shelter, pollination, seed dispersal
What is a stable community?
Where all species and abiotic factors are in balance, population sizes remain fairly constant
In a stable community, what happens to the population size of predators and prey?
They rise and fall in cycles
What are extremophiles?
Organisms living in very extreme environments
Give three examples of extreme environments.
High temperature, high pressure, high salt concentration
Give one example of an extremophile
Bacteria living in deep sea vents
How can population sizes and distributions be measured?
Using transects and quadrats
What is a line transect?
A line marked with a measuring tape which can be sampled at regular intervals
How can quadrats be used to estimate the number of organisms in an area?
They allow the numbers of organisms in a small sample of an area to be counted
What is variation?
Differences in characteristics of individuals in a population/species?
What factors can cause variation?
Genetic causes, environmental causes or a combination of both
What are genes?
Instructions for cells
What are genes made of?
DNA
How are genes passed on?
From parent to offspring through reproduction
What are genetic causes of variation?
The genes an individual inherits
