Download Ecology

13.1 Ecologists Study
Relationships
Introduction To Ecology
 Ecology – the study of living
things and their relationship with
each other and with the
environment
 *Ecology can be studied at different levels,
from a local to a global scale
Levels of Organization

1. Organism – an individual living
thing, such as an alligator

2. Population – group of same species
that lives in one area, such as a group
of alligators living in a swamp
Levels of Organization
3. Community – all of the living
things in a given area. Ex: alligators,
fish, plants, birds.
 4. Ecosystem –
all of the living and
nonliving things
in a given area.
Ex: All of the above and
soil, rocks, water, etc.

Levels of Organization
 5. Biome – a major regional or global
community of organisms, usually
characterized by the climate conditions
and plant communities that thrive
there.
◦ Examples: tropical, grassland, desert,
temperate, taiga, tundra
Levels of Organization

6. Biosphere – portion of the
Earth where all life exists
Ecological research methods
include…

Observation – the act of carefully
watching something over time.
◦ Direct: naked eye, binoculars
◦ Indirect: feces, recent kill
Experimentation – scientists can
perform experiments in the lab or the
field.
 Modeling – Using computer or
mathematical models to describe and
model nature

13.2 Biotic and Abiotic Factors
Every ecosystem includes both living and nonliving
factors
Biotic factors are living things, or
things that were once living
Examples: plants, animals, fungi, bacteria
 Each organism plays a particular role in
the ecosystem.

Abiotic Factors are nonliving
Examples: moisture, temperature, wind,
sunlight, soil.
 The balance of these factors determines
which living things can live in a particular
environment.

Biodiversity is important to an
ecosystem
Biodiversity is the assortment, or variety, of living
things in an ecosystem.
 Keystone species: A species that has an unusually
large effect on its ecosystem. The loss of a keystone
species from an ecosystem can have a ripple effect.
◦ Example: Beavers create dams which are an
ecosystem used by a wide variety of species.
◦ http://www.youtube.com/watch?v=kEh4r4iQiBU

13.3 Energy in Ecosystems


Life in an ecosystem requires a source of energy
Producers provide energy for other organisms in an
ecosystem.
◦ Producer: An organism that get their energy from
non-living resources. Example: Plants
 Also called autotrophs
 Get energy from photosynthesis or chemosynthesis
 Chemosynthesis: process by which an organism
forms carbohydrates using chemicals as an energy
source.
Energy In Ecosystems

Consumers are organisms that get their
energy by eating other living things
◦ Also called heterotrophs
◦ All consumers somehow depend on
producers for food.
◦ Examples: wolf, human, rabbit
13.4: Food chains and food webs

Food chains and food webs model the
flow of energy in an ecosystem.
Food Chains & Food Webs
Food chain: a model that
shows a sequence of
feeding relationships.
◦ Shows the transfer of
energy from one
organism to another
◦ Each level of
nourishment
in a food chain is
called a trophic level

Not all consumers are alike.
Herbivores: Eat only plants. Example: rabbits
Carnivores: Eat only animals. Example: lion
Omnivore: Eat both plants and animals. Example:
kangaroo rat.
 Detritivores: Eat detritus, or dead organic
matter.



◦ Examples: millipede

Decomposer: A type of detritivore that breaks
down organic matter into simpler compounds,
returning vital nutrients back into their
environment.
◦ Example: fungi
Other types of consumers…

Specialists: a consumer that primarily
eats one specific organisms or feeds on a
very small number of organisms.
◦ Very sensitive to changes in the availability of
prey.

Generalists: consumers that have a
varying diet (most species).
Energy flows from the lowest
trophic level to the highest trophic
level




Producer to primary
consumer to secondary
consumer to tertiary
consumer
Primary consumers are
herbivores (or omnivores)
Secondary consumers are
carnivores (or omnivores)
Tertiary consumers are
carnivores (or omnivores)

A food web is a model that shows the
complex network of feeding relationships
and the flow of energy within an
ecosystem.
Energy Pyramids

•
•

A pyramid of numbers shows the numbers of individual organisms at
each trophic level in an ecosystem.
Between each tier of an energy pyramid, up to 90 percent of the
energy is lost into the atmosphere as heat.
Only 10 percent of the energy at each tier is transferred from one
trophic level to the next.
A vast number of producers are required to support even a few
top level consumers.
tertiary
consumers
5
secondary
consumers
5000
primary
consumers
500,000
producers
producers
5,000,000
3.5 KEY CONCEPT
Matter cycles in and out of an
ecosystem.
• It changes form, but does not
disappear.
• The total amount of matter
remains the same.
http://www.youtube.com/watch?v=09_
sWPxQymA
Water cycles through the environment.
The hydrologic, or water, cycle is the circular
pathway of water on Earth.
 Organisms all have bodies made mostly of water.

precipitation
condensation
transpiration
evaporation
lake
groundwater
surface
runoff
water storage
in ocean
Elements essential for life also cycle
through ecosystems
-examples: oxygen, carbon

A biogeochemical cycle is the movement of a
particular chemical through the biological and
geological parts of an ecosystem.
The Oxygen Cycle

Oxygen can cycle indirectly through an
ecosystem by the cycling of other nutrients.
oxygen
photosynthesis
respiration
carbon
dioxide
 The

Carbon Cycle
Carbon is the building block of living
organisms.
◦
◦
◦
◦
◦
◦
◦
Carbon comes in all three forms (solid, liquid, gas)
CO2 gas
HCO3 (bicarbonate- dissolved in water)
Fossil Fuels (underground) oil, natural gas, coal
Carbonate rocks (limestone)
Dead Organic Matter
http://ed.ted.com/lessons/the-carbon-cycle-nathaniel-manning
carbon
dioxide
in air combustion
respiration
photosynthesis
respiration
decomposition
of organisms
fossil fuels
photosynthesis
carbon dioxide
dissolved in water

The nitrogen cycle mostly takes place
underground.
– Some bacteria convert gaseous nitrogen into ammonia through a
process called nitrogen fixation.
– Some nitrogen-fixing bacteria live in
nodules on the
roots of plants;
nitrogen in
others live
atmosphere
freely in
animals
the soil.
– Lightning
can split
plant
nitrogen
molecules in the
nitrates
nitrogen-fixing
bacteria in
atmosphere which
decomposers
nitrifying
roots
bacteria
ammonification
can add nitrogen
nitrites
nitrogen-fixing
ammonium
to the soil.
bacteria in soil
nitrifying
bacteria
denitrifying
bacteria
Nitrogen Cycle Continued
◦ Ammonia (NH3) released into the soil is transformed into
ammonium – some is taken up by plants
◦ Nitrifying bacteria change the ammonium into nitrate.
◦ Nitrate is taken up by plants and converted into organic
compounds like amino acids and proteins.
◦ Nitrogen moves through the food
web and returns to the soil during decomposition as
ammonium.
◦ This process is referred to as nitrogen assimilation
Phosphorus Cycle

The phosphorus cycle takes place at and below
ground level – it does not include an atmospheric
portion.
1. Phosphate is released by the weathering of rocks.
2. Plants and fungi found near plant roots are able to take up
phosphate
3. Phosphorus moves through the food web and returns to the soil
during
rain
decomposition.
geologic uplifting
– Phosphorus leaches
into groundwater
from the soil and
is locked in
sediments.
– Both mining and
agriculture add
phosphorus into
the environment.
plants
weathering of
phosphate from rocks
runoff
animalsphosphate
phosphate in solution
in soil
leaching
decomposers
sedimentation
forms new rocks