Download Ecology

Ecology
What is Ecology?
 Ecology
is the study of the interactions of
organisms with one another and with their
physical environment.
 Biosphere - part of the Earth in which life
exists.


Includes land, air, and water as well as life.
Living organisms are NOT distributed
uniformly throughout the biosphere.
The biosphere is large…
 …So
ecologists work with smaller units
called ecosystems.
 Ecosystem - consists of an area’s physical
features and living organisms.
 System-
a set of interacting or interdependent
components that form an integrated whole

Abiotic factors - physical features
 Ex.


elevation, humidity, rainfall
(SWATS: soil, water, air, temp, sunlight)
Biotic factors - living organisms
 Ex.
snails, worms, plants, insects
Members of Ecosystems are
Related
 Community
- all the populations of
organisms living in a given area.

Ecosystems rarely function independently of one
another because they are connected by both living
and non living features.
Ecological Succession
 Ecological
succession - an existing
community of organisms is replaced
by a different community over time.
 Can
occur where no living community
existed before (like a volcano arising
from the sea).
 Can also occur following a dramatic
change (like a forest fire).
 Succession
leads to a collection of
organisms called a climax
community.
Biomes

Biome - an environment that has a characteristic climax
community.

Terrestrial- associated with a land environment
1)
a.
2)
a.
b.
3)
4)
a.
b.
5)
6)

Tropical
Tropical Rain Forest
Grassland
Tropical Grassland
Temperate Grassland
Desert
Temperate
Temperate Deciduous Forest
Temperate Rain Forest
Taiga
Tundra
Aquatic- associated with a water environment



Freshwater- (rivers, streams, ponds, lakes, wetlands)
Estuaries
Marine (intertidal zone, coastal ocean, open ocean)
 Habitat-
an area that provides an
organisms with its basic needs for survival
 Endemic
species- a species found in its
originating location and is generally
restricted to that geographic area
 Non-native
species – species introduced
into an area outside of their rang by
accidental or deliberate human activity

-can also be called: introduced, invasive,
alien, nonindigenous, or exotic
Energy flow through
ecosystems
 Of
all the sun’s energy the reaches the Earth’s
surface, only about 0.1% is used by living things.
 Energy cannot be recycled or used again!

For this reason, we refer to the movement of
energy through an ecosystem as a flow, not a
cycle.
 Biochemical
conversion- the changing of organic
matter into other chemical forms such as fuels
 Bioenergetics- the study of energy flow (energy
transformations) into and within a living system
Energy flows through
ecosystems
 The
sun is the ultimate source of
energy for living things.
 Producers
- organisms that make their
own food via photosynthesis.
 Consumers - organisms that get their
energy directly or indirectly from
producers.


Primary consumers - also called herbivores;
plant eating animals.
Secondary consumers - animals that eat
primary consumers.
Energy flows through
ecosystems
 Trophic
level - each step in a series of
organisms eating other organisms.

At each higher trophic level, less and less of
the energy originally captured by the
producers is available.

This is because the energy obtained from
digested food is used to maintain metabolism.
 Only
about 10% of the energy from
one trophic level can be used by the
animals at the next trophic level!
Energy Flows Through
Ecosystems
 Herbivores
- organisms that eat only plants.
 Carnivores - organisms that eat only animals.
 Omnivores - organisms that eat plants and animals.
 Decomposers - organisms that obtain energy from
non-living organic matter
Energy
Pyramid
Ecosystem relationships
 Food
chain simplest feeding
relationship linking
animals and
plants in the
biosphere.
 Usually
contains 3-5
total organisms.
Ecosystem relationships
 Food
web complex
relationship formed
by interconnecting
and overlapping
food chains.
Biotic Interactions in an
Ecosystem
 Competition-
finite amount of resources to
compete over
 Predation- one species uses another as food
 Symbiosis-a close and usually obligatory
association of two organisms of different species
that live together, often to their mutual benefit



Commensalism –one organism benefits without
affecting the other
Parasitism –one organism benefits (the parasite), at
the expense of the other (host)
Mutualism – each organism benefits
Nutrients are recycled through
an ecosystem
 nutrients
are recycled and used again
and again.
 Biogeochemical cycle - nutrients use
these processes to move through the
biosphere.

Ex. Water, carbon, nitrogen, oxygen cycles
Nutrients are Recycled
Through an Ecosystem - Water
Cycle
 Water
cycle - movement of water
between the atmosphere and Earth.



Consists of alternating cycles of
evaporation and condensation.
Evaporation moves water molecules into
the air while precipitation returns it to Earth.
Some water sinks into the ground
(groundwater) while some runs along the
surface of the ground until it enters a river or
stream.
Nutrients are Recycled Through an
Ecosystem – Carbon Cycle
 Carbon-
required
for all organic
compounds
 Carbon Cyclemovement of
Carbon through
the biosphere
Nutrients are Recycled Through
an Ecosystem –Oxygen Cycle
Oxygen
Cyclemovement
of Oxygen
through the
biosphere
Nutrients are Recycled
Through an Ecosystem Nitrogen Cycle
 Nitrogen
- element required by living
organisms to build proteins.
 Nitrogen cycle - movement of nitrogen
through biosphere.

Most can’t be used directly by living
organisms - it must be converted into more
usable forms.
Nutrient limitation
 The
rate at which producers can capture
energy is limited by the amount of
available nutrients.
 Limiting factor - the nutrient that is in short
supply that limits an organism’s growth.