Transcript Chapter 4 PowerPoint

14.1 Habitat And Niche
KEY CONCEPT
Every organism has a habitat and a niche.
14.1 Habitat And Niche
Objectives
• Differentiate between a habitat and a niche
• Differentiate between competitive exclusion and
ecological equivalents
14.1 Habitat And Niche
Vocabulary
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Habitat
Niche
Competitive exclusion
Ecological equivalent
14.1 Habitat And Niche
A habitat differs from a niche.
• A habitat is all aspects of the area in which an organism
lives.
– biotic factors
– abiotic factors
• An ecological niche
includes all of the
factors that a
species needs to
survive, stay healthy,
and reproduce.
– food
– abiotic conditions
– behavior
14.1 Habitat And Niche
Resource availability gives structure to a community.
• Species can share habitats and resources.
• Competition occurs when two species use resources in the
same way.
• Competitive exclusion keeps two species from occupying
the same niche.
14.1 Habitat And Niche
• Competitive exclusion has different outcomes.
– One species is better suited to the niche and the other
will either be pushed out or become extinct.
– The niche will be divided.
– The two species will further diverge.
14.1 Habitat And Niche
• Ecological equivalents are species that occupy similar
niches but live in different geographical regions.
Madagascar
South America
14.1 Habitat And Niche
What are the 3 parts of an organisms ecological niche?
14.1 Habitat And Niche
What does the principle Competitive Exclusion say will
happen when 2 species compete for the same resource?
14.1 Habitat And Niche
If a group of mantella frogs were transported to the
ecosystem of the poison dart frogs, what might happen
to the 2 species populations?
14.1 Habitat And Niche
A bison and an elk live in the same habitat and feed on
the same grasses. Does this mean that the competitive
exclusion principle does not apply? Explain.
14.1 Habitat And Niche
Considering the competitive exclusion principle, why
may it be harmful to transport a species such as a
rabbit, to another habitat where it currently does not
exist?
14.2
14.1 Habitat And Niche
KEY CONCEPT
Organisms interact as individuals and as populations.
14.2
14.1 Habitat And Niche
Objectives
• Compare & Contrast interspecfic and intraspecific
competition
• Describe the 3 types of symbiosis
14.1 Habitat And Niche
Vocabulary
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Competition
Predation
Symbiosis
Mutualism
Commensalism
Parasitism
Parasite
Host
Predator
Prey
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Competition and predation are two important ways in
which organisms interact.
• Competition occurs when two organisms fight for the
same limited resource.
– Intraspecific
competition
– Interspecific
competition
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• Predation occurs when one organism captures and eats
another.
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• There are three major types of symbiotic relationships.
– Mutualism: both organisms benefit
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• There are three major types of symbiotic relationships.
– Commensalism: one organism benefits, the other is
unharmed
Ø
Human Our eyelashes
are home to tiny mites
that feast on oil
secretions and dead
skin. Without harming
us, up to 20 mites may
be living in one eyelash
follicle.
Commensalism
Ø Organism is not affected
+
+
Organism benefits
Demodicids Eyelash
mites find all they need to
survive in the tiny follicles
of eyelashes. Magnified
here 225 times, these
creatures measure 0.4
mm in length and can be
seen only with a
microscope.
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• There are three major types of symbiotic relationships.
– Parasitism: one organism benefits, the other is harmed
0
Parasitism
+
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Hornworm
caterpillar
The host hornworm
will eventually die as
its organs are
consumed
by wasp larvae.
_
Organism is not affected
0
Braconid
wasp
Braconid larvae
feed on their
host and
release
themselves
shortly before
reaching
the pupae
stage of
development.
Organism benefits
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• There are three major types of symbiotic relationships.
– Parasitism meet their needs as ectoparasites (such
as leeches) and endopaasites (such as hookworms)
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During the fall spawning of salmon, grizzly bears fight
over space on the banks of a river. What type of
competition is this?
14.2
14.1 Habitat And Niche
Describe and give an example of the 3 types of
symbiosis
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How are predation & parasitism similar? How do they
differ?
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After a lion has made a kill birds will sometimes arrive to
pick at the carcass. The birds would be considered
_________(A)_________________ while the lions would
be considered _________(B)_____________________
14.3
14.1 Habitat And Niche
KEY CONCEPT
Each population has a density, a dispersion, and a
reproductive strategy.
14.3
14.1 Habitat And Niche
Objectives
• Consider density and geographic dispersal as
characteristics of populations
• Describe 3 basic types of survivorship curves in relation
to reproductive strategies.
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Population density is the number of individuals that live
in a defined area.
• Population density is a measurement of the number of
individuals living in a defined space.
• Scientists can calculate population density.
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Geographic dispersion of a population shows how
individuals in a population are spaced.
• Population dispersion refers to
how a population is spread in
Clumped
an area.
dispersion
Uniform
dispersion
Random
dispersion
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• There are three types of dispersion.
– clumped
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• There are three types of dispersion.
– uniform
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• There are three types of dispersion.
– random
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Survivorship curves help to describe the reproductive
strategy of a species.
• A survivorship curve is a diagram showing the number of
surviving members over time from a measured set of births.
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• Survivorship curves can be type I, II or III.
– Type I—low level of infant mortality and an older
population
– common to large mammals and humans
– Type II—survivorship rate is equal at all stages of life
– common to birds
and reptiles
– Type III—very
high birth rate,
very high infant
mortality
– common to
invertebrates
and plants
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14.1 Habitat And Niche
An Organism has 10 offspring. Two of these offspring
die each year over a 5 year period. Is this organism
more likely to be a bird or insect? Explain.
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14.1 Habitat And Niche
KEY CONCEPT
Populations grow in predictable patterns.
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Objectives
• Describe 4 characteristics that affect population size
• Compare exponential and logistic population growth
• Identify factors that limit population growth
14.1 Habitat And Niche
Vocabulary
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Population growth
Immigration
Emigration
Exponential growth
Logistic growth
Limiting factor
Density-dependent limiting factor
Density-independent limiting factor
Carrying capacity
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Changes in a population’s size are determined by
immigration, births, emigration, and deaths.
• The size of a population
is always changing.
• Four factors affect the
size of a population.
– immigration
– births
– emigration
– deaths
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Population growth is based on available resources.
• Exponential growth is a rapid population increase due to an
abundance of resources.
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• Logistic growth is due to a population facing limited
resources.
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• Carrying capacity is the maximum number of individuals in
a population that the environment can support.
• A population crash is a dramatic decline in the size of a
population over a short period of time.
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Ecological factors limit population growth.
• A limiting factor is something that keeps the size of a
population down.
• Density-dependent limiting factors are affected by the
number of individuals in a given area.
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• Density-dependent limiting factors are affected by the
number of individuals in a given area.
– predation
– competition
– parasitism
and disease
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• Density-independent limiting factors limit a population’s
growth regardless of the density.
– unusual weather
– natural disasters
– human activities
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What 4 factors determine the growth rate of a
population?
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How does carrying capacity affect the size of a
population?
• Carrying capacity limits the size of a population
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What is the main difference between a densitydependant limiting factor and a density-independent
limiting factor? Give an example of each.
Density-Independant
Density-Dependant
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What might cause exponential growth to occur only for
a short period when a new species is introduced to a
resource filled environment.
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Give an example of how a symbiotic relationship could
cause a population to crash.
14.5
14.1 Habitat And Niche
KEY CONCEPT
Ecological succession is a process of change in the
species that make up a community.
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14.1 Habitat And Niche
Objectives
• Describe the process of primary succession
• Explain the difference between primary and secondary
seuccession
14.1 Habitat And Niche
Vocabulary
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Succession
Primary succession
Secondary succession
Pioneer species
Climax community
Lichen: a fungus and photosynthetic partner living in a
symbiotic relationship (mutualism)
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Succession occurs following a disturbance in an
ecosystem.
• Succession regenerates or creates a community after a
disturbance.
– a sequence of biotic changes
– damaged communities are regenerated
– new communities arise in previously uninhabited areas
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• There are two types of succession.
– primary succession — started by pioneer species
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• There are two types of succession.
– secondary succession — started by remaining species
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How is primary succession different from secondary
succession?
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Why are pioneer species so important for primary
succession?
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Does the process of primary succession take longer in
the tropical or arctic areas? Explain.
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Which reaches a climax community 1st, an area
undergoing primary or secondary succession? Explain
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During succession, what might be the limiting factor for
sun-loving mosses as taller plants begin to grow?
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At what point during primary succession does an
ecosystem provide the fewest habitats for an organism?
Explain.