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
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