Transcript File - Big Green Planet

Population Interactions
It is sometimes
useful to think
of the universe
as being
organized into
hierarchical
levels, from the
universe on top
to the atoms on
the bottom.
Spheres of the Earth
The Earth can be divided
into 6 spheres:
Atmosphere: The layer of gases
that surrounds the planet.
Lithosphere: The land, rocks,
abiotic portions of the soil.
Biosphere: The sum of all
ecosystems, both the biotic and
abiotic.
Hydrophere: The Earth’s water
Cryosphere: The Earth’s ice
Anthrosphere: The people.
Biosphere
Since it is the sum
of all ecosystems,
the biosphere
consists of all living
things, plus any
non-living things
that interact with
those living things.
Ecosystems
An ecosystem is a community of living (biotic) organisms and the nonliving (abiotic) environment it inhabits. The biotic and abiotic portions
of an ecosystem interact through nutrient cycling and energy flows.
Community
A community is the biotic portion of an ecosystem. It
includes all the living things that share an environment,
including their interactions with each other.
Populations
A population is a group of organisms of the same species
living in the same area at the same time.
Competition
A resource in an ecosystem usually occurs in a limited supply, so
organisms that require that resource must “battle” each other for the
resource. This battle is called competition.
There are two types of competition, intraspecific and interspecific.
Intraspecific Competition: Competition within the same species.
Competition
Interspecific Competition: Competition between different species.
Competition
Competitive Exclusion Principle: A theory first proposed by
Joseph Grinnell and later formulated by Georgy Gause based on
laboratory experiments. It states that two species cannot occupy a
single niche at the same time without one of the species eventually
crowding out the other. It is not seen very often in natural
ecosystems. Surprisingly, many species find a way to live in
balance with each other.
Symbiosis
Definition: A close and often long-term relationship between two
or more species. Most books identify three main types of
symbiosis:
1) Mutualism
1) Commensalism
1) Parasitism
The next few slides and videos show definitions and examples of
these relationships.
Mutualism
Definition: A relationship between two or more species in which
both/all species benefit and no species is harmed.
Example: Rhizobia bacteria in plant root nodules fix nitrogen for the plant
while gaining help maintaining a suitable environment for the bacteria
Examples of Mutualism
Example: Acacia ants live in acacia trees and protect the trees from plants that
might steal light from the tree and from animals that wish to use the tree for
food. In return, the ants get a sweet sap and other food produced by the tree.
Examples of Mutualism
Example: Lichens are a symbiotic relationship between fungi and algae or
other photosynthetic organisms. The fungi receive food from the
photosynthesis and the algae receive other nutrients and a way to live on
harsh surfaces, such as rocks.
Commensalism
Definition: A relationship between species in which one species benefits and
another species is neither harmed or helped..
Parasitism
Definition: A relationship between two or more species in which
one species gets its food from the other species. Parasitism does
not usually kill the host unless numbers of parasites get too high.
Still, there is a cost to the host. There are ectoparasites and
endoparasites.
Ectoparasites: Parasites that live on the outside of their host.
For example, fleas, mites, and the cuckoo and cowbirds
Endoparasites: Parasites that live on the inside of their host.
For example, worms, viruses, bacteria
Predation
Definition: A relationship between two or more species in which
one species feeds on another, resulting in its death.
Example: The owl uses finely tuned hearing/echolocation to find its prey.
Examples of Predation
Example: Killer whales sometimes work together, as predators often do, to
catch their prey.
Examples of Predation
Example: A cuttlefish can use camouflage to hide from its prey until it attacks.
Examples of Predation
Example: Big cats, such as lions, are notorious predators, as are crocodiles.
Watch in this video as the two predators go to work and the prey show some
of their defenses.
Herbivory
Definition: The act of an animal eating a green plant
Habitat
Definition: The place or ecological environment in which an organism
lives.
In a tree
Inside another organism
In the ocean
A deciduous forest
Under a rock
Paris
A swamp
Ecological Niche
Definition: The way in which an organism makes its living. The habitat
of the organism along with its food and any other resources or parts of
the environment that the organism has a relationship.