Species Interactions

Population

a group of organisms of the same species living in the same area at the same time, and are capable of interbreeding

Ecosystem

A community of interdependent organisms and the physical environment with which they interact.

Biotic factors

all the living components of an ecosystem such as plants, animals, fungi, bacteria and viruses, and all the interactions between the living components.

Producers

Plants that produce eat their own food

Consumers

animals that eat plants and other animals

Decomposers

organisms that break down the waste of other organisms

Abiotic factors

non-living factors that affect organisms (temperature, sunlight, water, salinity)

Niche

the particular set of abiotic and biotic conditions and resources on which an organism or a population depend

the ecological role of a species in an ecosystem.

Niches cannot overlap —> competition

Graph of environmental gradient

• optimal range —> where organisms are abundant

• tolerance range (range of physiological stress) —> less organisms

• range of intolerance —> organisms absent

Types of species interactions (6) -

• Predation

• Herbivory

• Parasitism

• Mutualism

• Disease

• Competition

Predation (3 points)

• When an organism acts as the predator and feeds on another organism, called the prey

• The predator depends on the prey for its own survival.

• The population size of the prey is controlled by the predators (negative feedback)

Herbivory

An interaction between species, where organisms, often animals, feed on plants.

Parasitism

a one-way relationship between two species where one, the parasite, takes resources from the host within giving anything in return. —> the parasite does not want the host to die

Mutualism

an interaction where both species benefit from one another and neither suffers. Mutualism is needed for ecosystems functioning and regeneration

Disease

• a departure from the normal state of functioning of any living organism and is marked by symptoms of illness

• Can be caused by other organisms: pathogens: An organism or substance that causes disease in another organism.

Competition

where organisms compete for a resource that is in limited supply

Intraspecific competition  

occurs when members of the same species compete for limited resources

Interspecific competition

occurs when members of different species compete for limited resources

Symbiotic relationships

relationships between organisms that live together

Ectoparasites

parasites living on the outside of the host (tick)

Endoparasites

parasites living on the inside of the host (tapeworm)

Competitive exclusion

interspecific competition can result in one species outcompeting the other

Selective pressure

an evolutionary force that causes a particular phenotype to be more favorable in certain environmental conditions

Community

A group of interacting populations of different species living within an ecosystem

Ecosystems obtaining energy

• Producers supply energy to consumers in ecosystems

• Energy is neither created nor destroyed —> producers get energy get, CO2, create glucose, consumed by consumers, then produce out CO2.