Species and Population Flashcards
Define species:
A group of organisms sharing common characteristics that interbreed and produce fertile offspring.
Define habitat:
The environment in which a species normally lives.
What is a niche?
A particular set of abiotic and biotic conditions and resources to which an organism or population responds. How an organism makes a living.
Define fundamental niche:
What an organisms niche would be if it had no predators in the environment
Define realised niche?
The actual conditions in which a species exists due to biotic interactions.
What are abiotic factors?
Non-living, physics factors that influence the organisms and ecosystem.
Example of abiotic factors?
Temperature, sunlight, pH, salinity, precipitation.
What are biotic factors?
The living components of an ecosystem
What are examples of interactions between organisms?
Predation, her victory, parasitism, mutualism, disease and competition.
What is an interaction?
When one species has an influence on the population dynamics of another.
What is a population?
A group of organisms of the same species living in the same area at the same time that are capable of breeding.
What are limiting factors?
Things that slow population growth as it approaches the carrying capacity of the system.
What is the carrying capacity of an ecosystem?
The maximum number of a species that can be sustainably supported by a given area.
What is a habitat?
The environment in which a species normally lives.
What three factors affect population size:
Natality (birth rate) Mortality (death rate) Migration
What are the two types of migrations
Immigration (moving into the area) Emigration (moving out of the area)
What is population density?
The average number of individuals in a stated area.
Can two species have the same niche?
No two species can inhabit the same ecological niche at the same time. If many species live together they must have slightly different needs and responses and so are not in the same niche.
When does competition take place?
All organisms in any ecosystem have some effect on each other and when any resource is in limited supply.
What is intraspecific competition?
Between members of the same species.
What is interspecific competition?
Individuals of different species could be competing for the same resource.
What is competitive exclusion?
When one species totally out competes the other.
How does competition effect carrying capacity of species?
It negatively effects BOTH species as they both use the same resources.
What is predation?
When one animal, the predator, eats another animal, the prey.
Can predation only occur with animals?
No plants can prey on plants/animals.
How does predation effect the organisms involved?
Positive for predator, negative for prey
What is herbivory?
An animal (herbivory) eating a green plant.
How does herbivory effect the organisms involved?
Positive for animal, negative for plant
What is parasitism?
The relationship between two species in which one species (the parasite) lives inside another (the host).
How does parasitism effect the organisms involved?
Positive for parasite, negative for host.
What is mutualism?
The relation between two or more species in which all benefit and none suffer.
What is commensalism?
When one partner is helped and the other is not significantly affected.
Give an example of mutualism:
Clown fish and sea anemones. The clown fish provide food in the form of their feces. The anemone’s stinging tentacles protect the clown fish from predators, but do not affect the fish.
Example of parasitism?
Vampire bats and intestinal worms
What is exponential growth?
When there are no limiting factors.
Why are top carnivores threatened?
Low numbers because it gets less efficient as you move up the food chain. They also have a limited diet so a change in their food prey has a knock on effect.
What in an s curve?
They start with exponential growth. No limiting factors effect growth at first.
However above a certain population size, the growth rate slows down gradually, finally resulting in a population of a constant size.
Where this levels off is called the carrying capacity
What is a j curve?
‘Boom and bust’
Exponential growth then sudden collapse.
