How Species Interact with Each Other

Environmental ScienceSpring 2011

ObjectivesExplain the difference between niche and

habitatGive examples of parts of a niche Describe the five major types of interactions

between speciesExplain the difference between parasitism

and predation Explain how symbiotic relationships may

evolve

NicheNiche: the unique role of a

species within an ecosystem Includes:

Species’ physical home Environmental factors necessary for

species’ survival All of species’

interactions withother organisms

Species Interactions5 major species interactions:

Competition Predation Parasitism MutualismCommensalism

CompetitionCompetition: different individuals or

populations attempt to use the same limited resources Can occur within and between species

CompetitionIndirect Competition:

Species can compete even if they never come into direct contact

Using the same plant for food at different times of the day

CompetitionAdaptations to Competition:

When 2 species with similar niches are placed together, one species will usually be more successful

Better adapted species would be able to use more the resources

Adaptations that decrease competition will also be advantageous for species whose niches overlap

CompetitionAdaptations to Competition:

Niche restriction occurs when each species uses less of the niche than it is capable of using Closely related species that use the same limited

resources within habitat

Predation

Predation: predator, prey interactionsPredator: organism that feeds on another

organismPrey: organism that is fed on Most organisms have evolved some

mechanisms to avoid or defend against predators

When predators only eat specific types of prey the sizes of each population tend to increase and decrease in linked patterns

ParasitismParasitism: relationship between parasite

and hostParasite: organism that lives in or on

another organism and feeds on itHost: organisms the parasite takes its

nourishment fromParasites usually do not kill their hosts

Advantage if lets host live for a long time

Mutualism Mutualism: close relationship between two

species n which each species provides a benefit to the other

Ex. Humans and bacteria

Commensalism Commensalism:

relationship in which one species benefits and the other species is neither harmed nor helped Ex. Birds nesting in trees

Symbiosis and CoevolutionSymbiosis: relationship in which two species

live in close associationMany types of species interactions are

considered symbioticOften used to describe a relationship in which

at least one species benefits

Symbiosis and CoevolutionCoevolution: species in close relationships

evolve togetherMay evolve adaptations that reduce harm or

improve the benefit of the relationship Ex. Flowering plants and their pollinators

Types of Interactions Between Two SpeciesInteraction Species A Species B Description

Competition Harmed Harmed Each species negatively affects the other

Predation Benefited Harmed Species A feeds on species B

Parasitism Benefited Harmed Species A feeds on species B

Mutualism Benefited Benefited Each species is helpful to the other

Commensalism Benefited Unaffected Species A benefits from species B, but species B is unaffected

Review AssignmentCreate a book that includes the 5 species

interactions. 1 species interaction per page, title page For each interaction include:

If species A and B are harmed, benefited, or unaffected (2 points)

A description of the interaction (4 points)An example with picture (2 points)Unique or extra information (2 points)

5 points for neatness, creativity, organization Total points = 55 points