Transcript Lesson 5.2 Species Interactions

Lesson 8.2 Species Interactions
The zebra mussel has completely
displaced 20 native mussel species in
Lake St. Clair.
Objectives
• Explain the difference between niche and habitat.
• Give examples of parts of a niche.
• Describe the five major types of interactions between
species.
• Explain the difference between parasitism and predation.
• Explain how symbiotic relationships may evolve.
Lesson 5.2 Species Interactions
The Niche
•
Describes an organism’s use of resources and functional
role in a community. A niche is different from a habitat. An
organism’s habitat is a location. However, a niche is an
organism’s pattern of use of its habitat.
•
Often restricted by competition
Ways in Which Species Interact
• Interactions between species are categorized at the level
where one population interacts with another.
• The five major types of species interactions are:
• Competition
• Predation
• Parasitism
• Mutualism
• Commensalism
Lesson 5.2 Species Interactions
Competition
• Organisms compete when they seek the same limited
resource.
• In rare cases, one species can entirely exclude another from
using resources.
• To reduce competition, species often partition resources,
which can lead to character displacement.
• Intraspecific Competition: among members of same
species
• Interspecific Competition: among members of two or more
different species
4 Types of Competition
• Competitive Exclusion
• Direct competition
between species
resulting in a winner
and loser
• One species is very
effective competitor by
excluding another
species from resources
entirely
• Occurs when two or
more species try to
occupy the same exact
niche
Fundamental and Realized Niche
• Fundamental:
• Full niche of species
• Realized
• Niche restricted by
competition
Resource
Partitioning
• Species partition,
or divide, the
resources they use
in common by
specializing in
different ways
Character Displacement
• When resource
partitioning can
lead to the
evolution of
physical
characteristics
among the
competing species
that reflect their
specialized role in
the environment.
Lesson 5.2 Species Interactions
Predation (+/–)
•
The process by which a predator hunts,
kills, and consumes prey
•
Defensive traits such as camouflage,
mimicry, and warning coloration have
evolved in response to predator-prey
interactions.
•
Some predator-prey relationships are
examples of coevolution, the process by
which two species evolve in response to
changes in each other.
Rough-Skinned Newt
Did You Know? A single roughskinned newt contains enough
poison to kill 100 people.
Unfortunately for the newt, its
predator, the common garter
snake, has coevolved
resistance to the toxin.
Predators and Prey
• All organisms need food and
consumers must eat other
organism to get it.
• Predators
• Consumers that actively hunt other
organisms
• Prey
• Organisms upon which the
predators feed on
Predator vs Prey
• Size of predator and prey populations are closely
linked
• Large prey population=more predators
• Small prey population=less predators
• Population Cycles
• Time it takes for a population to rise and fall
• Some take 10 years, some 4 years
• Lifespan of organisms plays a role
Parasitism
• A relationship in which one
organism feeds on the tissues
or body fluids of another.
• Examples: Ticks, Fleas, lice,
variety of worms
• Host
• Organism in which the parasite
feeds
• True parasite
• Adapted to live on or in the host
Parasitism Cont.
• Population size is related to size
of host
• Thrive in crowded host
populations
• Density-dependent limiting
factor because parasite is more
successful in a dense host
population
Symbiosis
• Relationship where two species live together closely
• Parasitism is a form of symbiosis
• One organism is harmed while one benefits
• Commensalism
• Relationship that benefits one species and neither helps or
harms the other
• Barnacles on a whale
Symbiosis Cont.
• Mutualism
• Relationship where both species benefit
• Ants and Acacia Tree
• Flowers and Insects
A remarkable 3-way mutualism appears
to have evolved between an ant, a
butterfly caterpillar, and an acacia in the
American southwest. The caterpillars
have nectar organs which the ants drink
from, and the acacia tolerates the
feeding caterpillars. The ants appear to
provide some protection for both plant
and caterpillar.
Videos
• Predator Vs Prey Video
• http://www.youtube.com/watch?v=pVX49KhH0mc
• Parasitism
• http://www.youtube.com/watch?v=EWB_COSUXMw
• Symbiotic Relationships
• http://www.youtube.com/watch?v=pMN1zI2Dm4c
8.2 Quiz
• 1. Explain how competition can affect an organism’s niche.
• 3. The human digestive tract is filled with bacteria. The bacteria
live in the body and get nutrients while helping to digest food.
What kind of species interaction is this-mutualism or
commensalism? Is it symbiotic? Explain
• 4. Copy the chart below and place a (+) or (-) to indicate the
species interaction. Interaction
Effect on Species Effect on Species
A
Commensalism
Competition
Herbivory
Mutualism
Parasitism
Predation
B