Transcript Chapter 17 - River Ridge

Chapter 17
Ecosystems
I. What is an Ecosystem?
A. Organisms interact with each other and
their environment.
1. All of earth’s inhabitants are
interwoven in a complex web of
relationships.
2. In 1866, Ernst Haeckel gave the name to
the study of how organisms fit into their
environment-ecology.
3. Ecology-the study of the interactions of
living organisms with one another and
with their physical environment.
4. Habitat- The place where a particular
population of a species lives.
5. Community- The place where a particular
population of a species lives.
6. Ecosystem-Community and all the
physical aspects of its habitat.
7. Abiotic factors- The physical aspects of a
habitat.
8. Biotic factors-Living organisms in a
habitat.
B. Ecosystems support Diverse
Communities
1. The number of species living within an
ecosystem is a measure of its biodiversity.
2. The number of animals, trees, plants,
shrubs, insects, fungi, ect is an example of
biodiversity.
C. Ecosystems change over time.
1. When a volcano forms a new island, a
glacier recedes and exposes bare soil, or a
fire burns an area, new habitat is created.
2. The first organisms to live in new habitat
are small fast growing plants called
pioneer species.
Pioneer species
Succession
3. A somewhat regular
progression of species
replacement is called
succession.
Primary succession
4. Succession that
occurs where plants
have not grown before
is called primary
succession.
Secondary succession
5. Succession that
occurs in areas where
there has been
previous growth, such
as in abandoned fields
or forest clearings is
called secondary
succession.
D. Glacier Bay
1. A good example of
primary succession is
a receding glacier.
II. Energy Flow in Ecosystems
A. How energy moves through ecosystems.
1. Everything that organisms do in
ecosystems-running, breathing and
growing, requires energy.
B. The primary energy source.
1. The rate at which organic material is
produced by photosynthetic organisms in
an ecosystem is called primary
productivity.
2. Organisms that first capture energy, the
producers, including plants some kinds of
bacteria and algae.
3. Consumers are those organisms that
consume plants or other organisms to
obtain energy.
C. Trophic levels
1. Trophic level- a graphic organizer based
on the organism’s source of energy.
2. The path of energy through the trophic
level is called a food chain.
3. Herbivores-animals that eat plants or other
primary producers.
4. Carnivores- Animals that eat herbivores.
5. Omnivores- animals that eat both plants
and animals.
6. Detritivores- Organisms that obtain their
energy from eating dead bodies.
7. Decomposers- bacteria and fungi are
decomposers because they cause decay.
Food web
D. Energy is lost in a food chain
1. During energy transfer of energy within an
ecosystem, energy is lost as heat.
2. An energy pyramid is a diagram in which
each trophic level is represented by a
block and the blocs are stacked on top of
one another, with the lowest trophic level
on the bottom.
E. Trophic levels are limited
1. Most terrestrial ecosystems involve only
three, or rare instances, four levels.
2. See figure 17.10 in book!
3. It takes 10 times more grain to feed a cow
to feed us than if we were to eat only
grain.
4. Biomass is the dry weight of tissue and
other organic matter found in a specific
ecosystem.
17.3 Ecosystems Cycle Materials
A. Materials cycle between living and non
living things.
1. Humans throw away tons of garbage
every year as unwanted or unusable.
2. Nature does not throw anything away.
3. In each biogeochemical cycle, a pathway
forms when a substance enters living
organisms such as trees from the
atmosphere, water or soil; stays for a time in
the living organism; then returns to the
nonliving environment.
B. The water cycle is driven by
the sun.
1. Ground water, which is water retained
beneath the surface of the Earth.
2. After passing through a plant, the water
moves into the atmosphere by evaporating
from the leaves, a process called
transpiration.
The water cycle
C. The carbon cycle
1. Carbon also cycles between the nonliving
environment and living organisms.
2. Carbon atoms may return to the pool of
carbon dioxide in the air in three ways.
3. Respiration-organisms breathing.
4. Combustion- Burning
5. Erosion- Sediments being moved and
transported.
D. Plants and bacteria take part in
the phosphorus and Nitrogen cycle.
1. Assimilation- The absorption and
incorporating of nitrogen into plant and
animal compounds.
2. Ammonification- The production of
ammonia by bacteria during the decay of
nitrogen containing urine.
3. Nitrification- the production of nitrate
from ammonia.
4. Denitrification- is the conversion of nitrate
to nitrogen gas.
5. The growth of plants in ecosystems is often
limited by the availability of nitrate and
ammonia in the soil.