Module 3 Flashcards
What is a selection pressure
Factors that exist in an environment that make it easier for some organisms to survive
What are the two types of selection pressures
Abiotic and biotic factors
Give example of abiotic factors
Availability of food, climate, water
Give examples of biotic selection pressures
Predators, competition of mate, food , disease
State a type of selection pressure
Directional selection
Define directional selection
Natural selection that favours one extreme of the population for that trait
Abundance refers to
The numbers of a population
Distribution refers to
The spread of a population
Formula for abundance
Number of individuals/ size of area
What is the carrying capacity
The maximum equilibrium number of individuals of a species that can be supported indefinitely in a given population
What causes a carrying capacity
Resources becoming limited
Define symbiosis
Relationship between 2 species living in close proximity in which at least 1 of them benefits
State the three types of symbiosis
Mutualism, Parasitism and Communalism
Explain mutualism
Both species benefit from the interaction
Example of mutualistic relationship
Honey eater and grevilla (flower)
Explain parasitism
One species (parasite) benefits from the interaction while the host is harmed but not killed
Example of parasitism
Tick and dog
Explain commensalism
One species benefits from the interaction while the other neither benefits or is harmed
Example of commensalism
Cattle and egret
Define intra specific competition
Between same species
Interspecific competition is and an example is
Between different species
Cheetah and lion 🦁
Define disease
A condition that adversely affects the normal functioning of an organism
What factors influence the distribution and abundance of populations in ecosystems
Predation, competition, climate
Calculate estimated abundance formula for plants
(Total number of plants/(area of each quadrant * number of quadrants)) X total area