Communities, Niches and Habitats

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Communities, Niches and Habitats
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Communities

• An ecological unit composed of a group of
  populations of different species occupying a
  particular area, interacting with each other and
  their environment.
• Each organism within the community has its own
  habitat and its own niche or very specific role
  to play in the community.

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Ecosystem

• An ecosystem is the interaction of the biotic
  factors in a community together with all of the
  abiotic factors of the environment that affect
  that community.

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Habitat

• A habitat is the place where living things live.
• It is more than just a home it includes the whole
  surrounding area.
• The habitat provides the animal or plant with
  food or shelter.

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People and their habitats

• People can live all over the world.

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• We can do this because we are able to build
  homes for different conditions.

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Also we can change our clothes to best suit the
temperature around us.
Animal skin and fur act as insulators and keep
heat in.
White clothes reflect the heat
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Animals and plants

• Most plants and animals are specially adapted to
  survive in a particular habitat.
• They have developed special features to suit the
  demands of their environment.
• This is called adaptation.

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• All birds have similar characteristics.
• But many water birds have features that are
  different from those birds that live on land.

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• Some animals are camouflaged to blend in with
  their surroundings.
• This keeps them safe as it is more difficult
  for other animals to see them or catch them for
  food.

These zebra could easily be mistaken for
bushes from a distance.
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• Aquatic animals have streamlined bodies to
  move more easily in the water.

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• These animals have adapted to live in the hot
  climate of the desert.

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• These animals have adapted to be more suited to
  cold temperatures.

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• Even plants have adapted to their habitats.

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Animals and plants help each other

• Plants and animals depend on each other for a
  wide variety of things.

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Niches
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Niche

• Each organism within a community has a niche.
• An organisms niche is its functional role within
  the community, including its activities and
  relationships, its address, its job or
  function within the community, and how it
  interacts with other organisms.

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What is a Niche

• Fundamentally, your niche is how you get food
  every day.
• Remember that food is simply the way organisms
  turn matter into energy so they can do work.
• The primary work of organisms is to survive and
  reproduce.

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What is a Niche

• The simplest way to think of a niche is it is
  either who is eating who, usually from different
  species.
• OR
• Who is reproducing and who isnt from the same
  species.
• OR
• Who is causing someone else to get eaten from the
  same or similar species.

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Niche Differences

• The niche of each species is a little different
  to avoid competition.
• Different species, even closely-related ones,
  will have different food preferences,
  seasonality, daily feeding rhythms, and location
  within the habitat.
• Otherwise, Gauses principal (The Competitive
  Exclusion Principle) says that one species must
  go extinct.

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Similar Species

• For some species of katydids within the same
  genus, the difference may be as subtle as a
  preference for perching on the top vs the middle
  of a stem on a grass plant.

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Types of Niches

• There are many types of niches. The most
  fundamental are
• Producers or Autotrophs
• These are organisms that make their own food.
• Consumers or Heterotrophs
• These are organisms that cannot make their own
  food.
• Scavengers
• Consumers that eat the flesh of dead animals they
  did not kill.
• Decomposers or Detritivores
• These are consumers that break down the bodies of
  dead plants and animals.

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Food Chains

• A food chain is a pathway that tells us what eats
  what when two populations interact within a
  community.

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Food Web

• A food web is the connection of all of the food
  chains within the ecosystem.

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Producers

• An organism that can make its own food is a
  producer.
• Autotroph
• Source of all food in an ecosystem.
• Capture light energy from sunlight and stores it
  as food (chemical) energy.

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Consumers

• Consumers are heterotrophs, or living things that
  cannot make food for themselves.
• A food chain contains several kinds of consumers,
  each of which occupies a different trophic level.
  
• Herbivores, carnivores, omnivores

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Consumer Tropic Levels

• Primary consumers eat producers (herbivores)
• Secondary consumers eat primary consumers
  (carnivores)
• Tertiary consumers eat secondary consumers
  (carnivores)
• Scavengers are carnivores that feed on the bodies
  of dead organisms.

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Decomposers

• Help break down wastes and dead organisms and
  return the raw materials to the environment
• Bacteria and fungi

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Food Chains

• Series of events where one organism eats another
  and obtains energy.
• First organism in chain is the producer.
• The second organism is the consumer that eats the
  producer.

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PlanktonCrabSealOrca This is only one possible
chain in a marine ecosystem.
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Come up with an example to fill in the blocks of
a food chain in two different ecosytems.
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Food Webs

• Consists of many overlapping food chains in an
  ecosystem.
• Some organisms may play more than one role by
  changing consumer levels.

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What happens in a food web if one or more of the
organisms disappear?
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Which animals are carnivores and herbivores?
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Energy Pyramids

• A diagram that shows the amount of energy that
  moves from one feeding level to another in a food
  web.
• Represented in a triangle with the most energy at
  the producer level.

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Energy Loss and Use

• Only 10 of energy is transferred to next higher
  level.
• 90 of energy is used by organisms life
  processes.
• Due to energy loss, ecosystem cannot support many
  feeding levels.

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Why are ecological interactions important?
Interactions can affect distribution and
abundance.
Interactions can influence evolution.
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Competition two species share a requirement for
a limited resource ? reduces fitness of one or
both species
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Ecological effects of competition
Intraspecific competition between individuals
of the SAME species
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Ecological effects of competition

• Interspecific competition between individuals
  of DIFFERENT species

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Interspecific interactions

• These are interactions among organisms of
  different species.
• These interactions are Either
• Beneficial to one or both of the species
  involved.
• Or detrimental to one of the species involved.
• What would we call interactions between organisms
  of the same species?

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competitive exclusion principle
If two species have the same niche, the
stronger competitor will eliminate the other
competitor.
Complete competitors cannot coexist.
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Complete competitors cannot coexist. Competitive
exclusion is reached more slowly with
higher resource abundances. Stable coexistence
requires niche differentiation, such that
members of each species compete more strongly
among themselves than with members of the
other species. ? (intraspecific gt
interspecific)
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What is the niche?

• set of conditions
• within which an organism
• can maintain a viable
• population
• multi-dimensional
• with as many
• dimensions as their
• are limiting conditions

ecological niche
light intensity
okay
temperature
salinity
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The niche of a species may contract in the
presence of a competitor species. This
phenomenon leads to resource (niche) partitioning
and coexistence among functionally similar
species. The narrower niche resulting from
competition is called the realized
niche. What happens if the competitor is
removed?
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Types of Relationships

• Symbiosis
• Any relationship that involves two (or more)
  species living together and interacting.
• This is a general term which includes predation,
  parasitism, commensalism, mutualism, etc., but
  often is used to mean mutualism.

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Types of Relationships

• Predation
• When a larger animal eats other, smaller
  animals.

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Types of Relationships

• Commensalism
• A relationship between two species that is
  beneficial to one but of neutral benefit to the
  other.

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Types of Relationships

• Mutualism
• A relationship between two species where both
  benefit.

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Types of Relationships

• Parasitism
• When a smaller organism feeds on a larger,
  weakening or killing it.
• This is a relationship where one organism
  benefits and the other is harmed.
• Often the host is not killed outright.
• Because a parasite lives in/on the body of its
  host and needs the host to remain alive, it is
  usually advantageous for the parasite to not kill
  its host.
• Humans and domestic animals are occasionally
  infected with or bothered by tapeworms,
  roundworms, mosquitoes and/or leeches.