chapter 8.2: Community Ecology & Species Interactions 🌿 Knowt Import Ready

Intraspecific competition

Competition over resources among individuals of the same species.

Community ecologists

Scientists who study the interaction of species with one another and recognize that competition over a resource may define which species survive and which ones do not.

Competitive exclusion principle

The principle stating that two species competing for the same limiting resource cannot coexist.

Resource partitioning

When two species divide a resource based on differences in behavior or lifestyle.

Types of resource partitioning

The three types of resource partitioning are temporal, morphological, and spatial.

Temporal resource partitioning

When two species use the same resource but at different times.

Example of temporal resource partitioning

Owls and hawks use the same resource but hunt at different times.

Morphological resource partitioning

Involves using similar but not exactly the same resources because of differences in morphology.

Morphological

Refers to the physical characteristics of an organism.

Spatial resource partitioning

When species divide resources based on different locations or areas within a habitat.

Example of spatial resource partitioning

One plant species may develop deep roots to access water below ground, while another keeps roots close to the surface to access rainfall or surface water.

Predation

When one living organism uses another living organism as a food resource.

True predators

Animals that kill and consume another animal (called their prey) as food.

Herbivores

Animals that consume plants.

Scavengers

Animals that find and eat animals that another predator has already killed or that died naturally.

Predator-prey interactions

Interactions that affect both population size and the distribution of populations across an ecosystem.

Keystone predators

Predators that play an important role in maintaining ecosystem stability.

Keystone species

A species that has a large effect on maintaining ecosystem structure and stability. It is named after the keystone of an archway, the stone at the center that keeps the entire arc from collapsing.

Predation pressure

The pressure of being preyed upon by predators.

Ways organisms deter predators

1. Chemical defense 2. Mimicry 3. Camouflage.

Chemical defense

Some plants and animals have developed chemical compounds that make them bad tasting or even poisonous when consumed.

Mimicry

Some species have evolved to look or act like a species that has a good defense.

Benefit of mimicry

The species using mimicry benefits from looking like another species that has well-developed and well-known defenses.

Camouflage

Some organisms hide in plain sight by taking on the appearance of their immediate environment.

Coevolution

The change in physical or behavioral characteristics of species as a result of interactions with another species over a long period of time.

Symbiosis

A close interaction between species where one species depends on another to survive.

Types of symbiosis

The three types of symbiosis are mutualism, commensalism, and parasitism.

Mutualism

A symbiotic relationship between two species in which both species benefit.

Example of mutualism

Some plants experience mutualism with nitrogen-fixing bacteria that live on their roots.

Commensalism

A symbiotic relationship between two species in which one benefits and the other neither benefits nor is harmed.

Parasitism

A form of predation where a parasite benefits from consuming another organism's tissue while the host is harmed by the loss of nutrients.

Difference between predation and parasitism

Parasitism is a form of symbiosis where the host must continue living for the parasite to benefit. In predation, the predator ends the life of the prey organism.

Fundamental niche

All the places a species could successfully inhabit if there were no other species to compete with.

Realized niche

The smaller portion of the environment that a species inhabits within its tolerance limits because other organisms share the environment.

Indicator species

Species that are very sensitive to changes in their environment.

Niche generalists

Organisms that adapt to live in a variety of habitats.

Niche specialists

Organisms that can successfully survive only in a very confined set of conditions.

Niche

The lifestyle of an organism and the role it plays in its community.