Ecosystems and Communities

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Ecosystems and Communities
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What is Climate?
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• Weather is the day-to-day condition of Earths
  atmosphere at a particular time and place
• Climate refers to the average, year-after-year
  conditions of temperature and precipitation in a
  particular region.

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The Greenhouse Effect

• What is it?
• A natural situation in which heat is retained by
  a layer of greenhouse gases.

• What causes it?
• Carbon dioxide, methane, water vapor, and a few
  other atmospheric gases trap heat energy and
  maintain Earths temperature range.

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Effects of Latitude on Climate

• Because earth is a sphere that is tilted, solar
  radiation hits Earth at different angles
• 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

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Heat Transport in the Biosphere

• 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

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Biotic Factors

• 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

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Abiotic Factors

• 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.

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The Niche

• 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!

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The Niche

• No two species can share the same niche in the
  same habitat.
• Different species can occupy niches that are very
  similar

• 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.

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Community Interactions

• Community interactions, such as competition,
  predation, and various forms of symbiosis, can
  powerfully affect an ecosystem.

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Competition

• Competition occurs when organisms of the same or
  different species attempt to use an ecological
  resource in the same place at the same time.
• Resource refers to any necessity of life, 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.

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Predation

• Predation is an interaction in which one organism
  captures and feeds on another organism.
• The predator is the organism that does the
  killing.
• The prey is the food organism, the organism that
  is being hunted/eaten.

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Predation
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Symbiosis

• Symbiosis is any relationship in which two
  species live closely together.
• Symbiosis means living together
• Three main classes of symbiosis
• Mutualism
• Commensalisms
• Parasitism

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Mutualism

• Mutualism is when both species benefit, they help
  each other.
• 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.

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Mutualism
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Commensalisms

• Commensalism is when one member of the
  association benefits and the other is neither
  helped nor harmed.
• Example barnacles attach themselves to a whales
  skin.
• The barnacles dont 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.

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Commensalisms
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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

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Parasitism
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Ecological Succession

• 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.

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Ecological Succession

• 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.

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Primary SuccessionStages

• 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.

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Lichens and Mosses (pioneer species)
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Succession
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Secondary Succession

• Secondary succession happens when land is
  cleared and plowed for farming and is abandoned
  or when wildfire burns woodlands.