Download Muscular System - walker2011

Ecology
Chapter 2

Ecology - The study of interactions that take
place between organisms and their
environment
Levels of Ecological Organization



Organism – an individual living thing
Species – a group of very similar organisms
that can interbreed and produce fertile
offspring
Hybrids are not species

Examples


Ligers
Mules
Levels of Ecological Organization




Population – organisms of the same species
that live in the same place and at the same
time
Community – different populations of different
species that live in the same place at the
same time
Ecosystem – a community of living organisms
plus their non-living environment
Biosphere – all the combined ecosystems of
the world where organisms can live
Biotic vs. Abiotic


Biotic factors – living
organisms in an
ecosystem
Examples:




Bee
Dandelion
Oak tree
Deer


Abiotic factors –
non-living parts of an
ecosystem
Examples




Water
Air
Soil
Rocks
Ecological Relationships



Niche – an organism’s role in its ecosystem
Habitat – the place where an organism lives
Example

Lion’s niche and habitat
Ecological Relationships

Predator-Prey


Predator – an animal that captures and eats a
member of another species
Prey – an animal that is subject to being caught
and eaten
Ecological Relationships



Herbivore – an animal
that eats only plants
Carnivore – an animal
that only eats other
animals
Omnivore – an animal
that eats plants and
animals
Ecological Relationships


Competition – the conflict between organisms
when they try to use the same resources at
the same time
Some resources



Food
Mating
Habitat
Ecological Relationships


Symbiosis – living together
Symbiotic Relationships (involves two
species)

Mutualism – both species benefit

Ex. – Insect and flower
Ecological Relationships

Symbiotic Relationships

Commensalism – only one species benefits but
the other is neither helped nor harmed

Ex. – Whale and barnacle
Ecological Relationships

Symbiotic Relationships

Parasitism – one organism benefits at the
expense of another organism


Ex. Tick and dog
Cuckoo

Brood parasite
Energy Flow in Ecosystems

Producers (or autotrophs) – organisms that
make their own food usually by using energy
directly from the sun


Ex. - plants
Consumers (or heterotrophs) – organisms
that cannot make their own food and must
get energy by eating producers or other
consumers

Ex. - animals
Energy Flow in Ecosystems





Decomposers (or saprotrophs) – organisms
that eat dead or decaying organisms
Primary consumer – eats producers
Secondary consumer – eats a primary
consumer
Tertiary consumer – eats a secondary
consumer
Quaternary consumer – eats a tertiary
consumer
Energy Flow in Ecosystems

Food chain – a simple representation of how
energy is passed from a producer to
consumers
Energy Flow in Ecosystems

Food web – a more complex representation
of how energy is passed from producers to
consumers in an ecosystem
Energy Flow in Ecosystems


Trophic level –
organism that
represents a feeding
step
Energy pyramid – a
representation in the
shape of a pyramid that
shows how energy is
passed from one
trophic level to the next
Energy Flow in Ecosystems


Most energy is located
at the producer level
As the trophic level
increases, 10% of
energy is lost
Ecological Succession


Ecosystems are constantly changing.
Ecological succession – a gradual process of
change and replacement of the types of
species in a community.
Primary Succession

Primary succession – a type of succession
that occurs on a surface where no ecosystem
existed before

Example: Hawaii islands
Primary Succession

Pioneer species – a species that colonizes an
uninhabited area and that starts an ecological
cycle in which many other species become
established.
Primary Succession


Lichen and bacteria are the pioneer species
Mosses are usually the second organisms to
form
Secondary Succession


Secondary succession occurs on a surface
where an ecosystem has previously existed.
Secondary succession can occur in
ecosystems that have been disturbed or
disrupted by humans, animals, or by natural
process such as storms, floods, earthquakes,
or volcanic eruptions.
Secondary Succession

Climax community – the final, stable
community in equilibrium with the
environment
Climax
community
Secondary Succession



Old-field succession is a type of secondary
succession that occurs when farmland is
abandoned.
When a farmer stops cultivating a field,
grasses and weeds quickly grow and cover
the abandoned land.
Over time, taller plants, such as perennial
grasses, shrubs, and trees take over the
area.