Studied by 3 people
What is a species?
A group of organisms sharing common characteristics that interbreed and produce fertile offspring
What is a habitat?
An environment which a species lives. This consists of abiotic (non-living) and biotic (living) factors
What is a niche?
Where, when and how an organism makes a living
NOTE: there are differences between what niche the species occupies (fundamental niche) and what it actually occupies (realised niche).
What is a fundamental niche?
The full potential of what can be occupied
What is a realised niche?
What the species actually occupies
What is a population?
Group of organisms of the same species living in the same area at the same time and are capable of interbreeding
What are abiotic factors?
Non-living factors that influence the organisms and ecosystems
What are biotic factors
Living components of an ecosystem that directly or indirectly affect another organism
What are ecosystems?
Made up of organisms and the physical environment and the interactions between the living and non-living components between them.
Examples of abiotic factors
sunlight, temperature, salinity, pH, pollutants
Why are abiotic factors important?
They determine ecosystems and their adaptations
examples of biotic factors
organisms, their interactions or their work
INCLUDES: predation, herbivory, parasitism, mutualism, disease and competition
What is the carrying capacity?
The maximum number of a species that can be sustainably supported by a given area
What are limiting factors?
Factors that slow down growth of a population as it reaches its carrying capacity
What are population dynamics?
The study of factors that cause changes to population sizes.
All interactions result in one species having an effect on the population dynamics and the carrying capacity of the environment.
What is symbiosis?
A relationship where two organisms live together
symbiosis
what is parasitism?
A relationship between two species where one (the parasite) lives in or on the other (the host) gaining its food from it.
e.g. ticks, tape worms
Two types of parasites are…
Endoparasites: live inside the host
Ectoparasites: live on the surface of the host
symbiosis
What is mutualism?
Relation between two or more species where all benefit and none suffer
Example of mutualism
i.e. lichen
= fungus on top of lichen benefits by obtaining sugars from algae
= algae benefits from minerals and water fungus absorbs and passes onto algae
symbiosis
What is commensalism?
When one partner is helped and the other is not significantly harmed
Example of commensalism
i.e. fern growing halfway up a tree trunk
What is competition?
when resources are limited, populations compete in order to survive
Two types of competition
intraspecific competition: Within species
interspecific competition: between different species
no two species can occupy the same niche so the degree to which niches overlap determines the degree of interspecific competition
What is competitive exclusion?
One species out-competes the other
What is predation?
When one animal, the predator, eats another animal, the prey
includes plants eating plants
can be beneficial since it strengthens the breeding pool by eliminating weaker organisms
What is herbivory?
Animals that feed on plants
(some plants have defence mechanisms against this)
What are S and J population curves?
Describe a generalised response of populations to a particular set of conditions
What are S curves?
start with exponential growth (no limiting factors affect the growth at first)
above a certain population size, the growth rate slows down resulting in a population of a constant size
Numbers stabilise at the carrying capacity
What are J curves?
Shows a boom and bust pattern
rapid growth continues well past carrying capacity
Then suddenly collapses (dieback)
Does not show gradual slow down of population size
Controlled by abiotic factors
Note 
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