Transcript Ecosystems and Communities

Ecosystems and
Communities
What is Climate?
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Weather is the day-to-day condition of
Earth’s atmosphere at a particular time
and place
Climate refers to the average, yearafter-year conditions of temperature
and precipitation in a particular region.
The Greenhouse Effect
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What is it?
A natural situation in
which heat is
retained by a layer
of greenhouse gases.
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What causes it?
Carbon dioxide,
methane, water
vapor, and a few
other atmospheric
gases trap heat
energy and maintain
Earth’s temperature
range.
Effects of Latitude on Climate
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Because earth is a sphere that is tilted, solar
radiation hits Earth at different angles
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This creates 3 main climate zones
Polar zones = cold zones at the poles
Tropical zones = warm zones around the
equator
Temperate zones = in between the polar and
tropical zones, vary from hot to cold throughout
the year
Heat Transport in the Biosphere
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The unequal heating of earths surface drives
winds and ocean currents spreading heat
Warm air at the equator rises, cool air at the poles
sinks creating wind currents
 Warm water at the equator rises, cool water at the
poles sinks creating ocean currents
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What Shapes an
Ecosystem?
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Biotic and Abiotic Factors
Niche
Community Interactions
Ecological Succession
Biotic Factors
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Ecosystems are influenced by a combination
of biological and physical factors.
Biotic Factors are the biological (living)
influences on organisms within an ecosystem.
Examples: all living things it might interact
with, birds, trees, mushrooms, bacteria…
Abiotic Factors
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Abiotic Factors are the physical (nonliving)
factors that shape ecosystems
Examples: temperature, precipitation,
humidity, wind, nutrient availability, soil type,
sunlight.
Together, biotic and abiotic factors
determine the survival and growth of an
organism and the productivity of the
ecosystem in which the organism lives.
The Niche
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A niche is the full range of physical and
biological conditions in which an organism lives
and the way in which the organism uses those
conditions.
A niche includes the type of food it eats, how
it obtains it, and which other species use the
organism as food. It also includes the
physical conditions it requires to survive and
it includes when and how it reproduces.
Everything an organism does to survive!
The Niche
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No two species can
share the same niche
in the same habitat.
Different species
can occupy niches
that are very similar
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Example
Three species of
North American
warblers live in the
same spruce trees,
but they feed at
different elevations
and on different
parts of the trees.
Community Interactions
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Community interactions, such as
competition, predation, and various
forms of symbiosis, can powerfully
affect an ecosystem.
Competition
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Competition occurs when organisms of the
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Resource refers to any necessity of life,
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same or different species attempt to use an
ecological resource in the same place at the
same time.
such as water, nutrients, light, food, or space.
The competitive exclusion principle, states
that no two species can occupy the same niche
in the same habitat at the same time.
Predation
 Predation is an interaction in which
one organism captures and feeds on
another organism.
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The predator is the organism that does
the killing.
The prey is the food organism, the
organism that is being hunted/eaten.
Predation
Symbiosis
 Symbiosis is any relationship in which
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two species live closely together.
Symbiosis means “living together”
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Three main classes of symbiosis:
Mutualism
 Commensalisms
 Parasitism
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Mutualism
 Mutualism is when both species
benefit, they help each other.
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Example: many flowers depend on
certain species of insects to pollinate
them.
The flowers provide the insects with
food (nectar or pollen) and the insects
help the flowers reproduce.
Mutualism
Commensalisms
 Commensalism is when one member of
the association benefits and the other is
neither helped nor harmed.
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Example: barnacles attach themselves to a
whale’s skin.
The barnacles don’t help or hurt the whale,
but the barnacles benefit because as the
whale swims, the constantly moving water
carries the food the barnacles eat to them.
Commensalisms
Parasitism
 Parasitism is when one organism lives on
or inside another organism and harms it.
 The parasite obtains all or part of its
nutritional needs from the other organism,
called the host
 Example: tape worms live in the intestine of
mammals, Fleas, ticks , and lice live on the
bodies of mammals, feeding on the blood and
skin of the host
Parasitism
Ecological Succession
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Ecosystems are constantly changing in
response to natural and human disturbances.
As an ecosystem changes, older inhabitants
gradually die out and new organisms move in,
causing further changes in the community.
These predictable changes that occurs in a
community over time is called Ecological
Succession.
Ecological Succession
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Succession that occurs where no soil
exists is called primary succession.
When a disturbance of some kind
changes an existing community without
removing the soil, then secondary
succession can take place.
Primary Succession
Stages
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The first species to populate the area
are called pioneer species. It is usually
lichens.
Lichens break down rock, as they die
they add organic material to help form
soil in which plants can grow.
After lichens, mosses appear, and
grasses take root, then seedlings and
shrubs can start to sprout.
Lichens and Mosses (pioneer species)
Succession
Secondary Succession
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Secondary
succession happens
when land is cleared
and plowed for
farming and is
abandoned or when
wildfire burns
woodlands.