Transcript Ecology Powerpoint

ECOLOGY UNIT
Chapters 20 & 21
Chapter 20 – Section 1
• Science Standard – S7L4: Students will
examine the dependence of organisms
on one another and their environment.
c. Recognize that changes in environmental
conditions can affect the survival of both
individuals and entire species.
Key Vocabulary words – page 674b
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Organism
Habitat
Biotic factor
Abiotic factor
Photosynthesis
Species
Population
Community
Ecosystem
Ecology
Living Things and the Environment
• Organism – a living thing which obtains
food, water, shelter, and other things it
needs to live, grow, and reproduce from
its environment.
• An environment that provides the things
the organism needs to live, grow, and
reproduce is called its habitat.
• Examples of habitats: forest, tropical rain
forest, ocean floor, and tree trunks.
• An organism interacts with both the
living and nonliving parts of its habitat.
• Biotic factors – living parts of a habitat;
examples – grass, plants, hawks, eagles.
• Abiotic factors – the nonliving parts of
an organism’s habitat; examples – water,
sunlight, oxygen, temperature, and soil.
Abiotic Factors
1.Water – all living things require water to
carry out their life processes; makes up a
large part of the bodies of most organisms;
human bodies – 65% water; plants and
algae need water with sunlight and carbon
dioxide to make their own food by
photosynthesis.
2.Sunlight – needed for photosynthesis
3.Oxygen – most living things require
oxygen to carry out life processes.
4.Temperature – ones that are typical in an
area determine the types of organisms
that can live there.
5.Soil – a mixture of rock fragments,
nutrients, air, water, and the decaying
remains of living things;
Levels of Organization
1.Species – group of organisms that are
physically similar and can mate with each
other and produce offspring that can also
mate and reproduce.
2.Population – made up of all the members
of one species in a particular area.
3.Community – all the different populations
that live close enough together in an area
(a particular area contains more than one
species of organisms) that interact by
using the same resources (food, shelter).
4.Ecosystem – made up of the community
of organisms that live in a particular area
along with their nonliving surroundings;
Examples – prairie, mountain streams,
oceans, forests.
• Ecology is the study of how living things
interact with each other and with their
environment.
• Ecologists – scientists who study ecology
and how organisms react to changes in
their environment.
Chapter 21 – Ecosystems and
Biomes
• Science Standard – S7L4: Students will
examine the dependence of organisms
on one another and their environment.
a. Demonstrate in a food web that matter is
transferred from one organism to another
and can recycle between organisms and their
environment.
b. Explain in a food web that sunlight is the
source of energy and that this energy move
from organism to organism.
Key Vocabulary – page 710 B
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Producer Consumer Herbivore Carnivore
Omnivore Scavenger
Decomposer
Food Chain Food Web
Energy Pyramid
Water Cycle Evaporation
Condensation
Precipitation Nitrogen Fixation
Climate
Biogeography Continental Drift
Dispersal
Exotic Species Biome Canopy Understory
Desert Grassland Savanna Deciduous tree
Coniferous Tree
Tundra
Permafrost
Energy Flow in Ecosystems
• Every organism has a role in the
movement of energy through its
ecosystem. This is necessary for the
ecosystem to work.
• Organism’s energy role - determined by
how it obtains energy and how it interacts
with other organisms.
• All organisms fill the energy role of
producer, consumer, or decomposer.
Producers
• Energy enters most ecosystems as
sunlight.
• Capture the energy of sunlight and store it
as food energy (plants, algae, and some
bacteria)
• Use the sun’s energy for photosynthesis.
• Can make its own food – green plant
• The source for all of the food in an
ecosystem.
Consumers
• Organisms that can not make their own food;
obtains energy by feeding on other organisms.
• Classified by what they eat:
herbivores – eat only plants; caterpillars
and deer
carnivores – eat only animals; lions and
spiders
omnivores – eat both plants and animals;
crows, bears, humans
scavenger – feeds on the bodies of dead
organisms; vultures and catfish
Decomposers
• Break down waste and dead organisms
and return the raw materials to the
ecosystem.
• “nature’s recyclers”
• Examples – mushrooms and bacteria
Food Chains
• Energy from the sun
is transferred to each
organism that eats a
producer, and then to
other organisms that
feed on these
consumers.
• The movement of
energy through an
ecosystem can be
shown in diagrams
called food chains
or food webs.
• Food chains show
only one path of
energy flow, food
webs show multiple
paths.
Food Webs
• Food webs consist of
many overlapping
food chains.
• An organism may
play more than one
role in an ecosystem.
Energy Pyramids
• Diagram showing the
amount of energy
available at each level of
a food web
• The most energy is
available at the
producer level.
• As you move up the
pyramid, each level has
less energy available
than the level below.
• Only 10% of the energy
at one level of a food web
is transferred to the next
higher level.
• The other 90% of the
energy is used for the
organism’s life processes
or is lost to the
environment as heat.
• As a result, there are
usually few organisms at
the highest level in a food
web.
Cycles of Matter
• The supply of matter in an ecosystem is
limited.
• Matter in an ecosystem includes water,
carbon, oxygen, nitrogen, and many other
substances.
• If matter can not be recycled, ecosystems
will quickly run out of the raw materials
necessary for life.
Water Cycle
• Water is essential for life.
• To ensure a steady supply, Earth’s water
must be recycled.
• The water cycle is a continuous process
by which water moves from Earth’s
surface to the atmosphere and back.
• Three processes – evaporation,
condensation, and precipitation – make up
the water cycle.
• Evaporation – process by which
molecules of liquid water absorb energy
and change to a gas.
1. Liquid water evaporates from oceans,
lakes, and other surfaces and forms water
vapor (gas) in the atmosphere.
2. The energy for evaporation comes from
the heat of the sun.
3. Living things give off water – plants
release water vapor from their leaves;
humans release liquid water in wastes and
water vapor when exhale.
• Condensation – process by which a gas
changes to a liquid
1. As the water vapor rises higher in the
atmosphere, it cools down.
2. The cooled vapor then turns back into
tiny drops of liquid water.
3. The water droplets collect around
particles of dust, eventually forming
clouds.
• Precipitation – rain, snow, sleet, or hail.
1. As more water vapor condenses, the
drops of water in the cloud grow larger.
2. Eventually the heavy drops fall back to
Earth as precipitation.
3. Most precipitation falls back into
oceans or lakes.
4. Some falls on land may soak into the
soil and become ground water or it may
run off the land, eventually flowing back
into a river or ocean.
Carbon and Oxygen Cycles
• Carbon is an essential building block in the
bodies of living things.
• Most organisms use oxygen for their life
processes.
• In ecosystems, the processes by which
carbon and oxygen are recycled are
linked.
• Producers, consumers, and decomposers
play roles in recycling carbon and oxygen.
The Carbon Cycle
• Producers take in carbon dioxide gas from the
air during photosynthesis.
• These producers use carbon from the carbon
dioxide to make food molecules.
• When consumers eat producers, they take in the
carbon-containing food molecules.
• When consumer break down these food
molecules to obtain energy, they release carbon
dioxide and water as waste products.
• When producers and consumers die,
decomposers break down their remains and
return carbon compounds to the soil and carbon
dioxide as a waste product.
The Oxygen Cycle
• Oxygen cycles through ecosystems.
• Producers release oxygen as a result of
photosynthesis.
• Most organisms take in oxygen from the
air or water and use it to carry out their life
processes.
• Human activities affect the levels of
carbon and oxygen in the atmosphere.
• When humans burn oil and other fuels,
carbon dioxide is released onto the
atmosphere.
• When humans clear forests for lumber,
fuel, and farmland, carbon dioxide levels
also rise.
The Nitrogen Cycle
• Nitrogen is necessary building block in the
matter that makes up living things.
• During the nitrogen cycle, nitrogen moves
from the air to the soil, into living things,
and back into the air.
• The air around us is 78% nitrogen gas, but
living things can not use nitrogen gas
(“free” nitrogen) because it is not
combined with other kinds of atoms.
• Most organisms can use nitrogen only
once it has been “fixed” or combined with
other elements to form nitrogen-containing
compounds – nitrogen fixation (performed
by certain kinds of bacteria). This bacteria
live in nodules (bumps) on the roots of
legumes – beans, peas, peanuts, alfalfa,
clover which feed on the plant’s sugars.
This supplies the plant with nitrogen in a
usable form.
• Once the nitrogen has been fixed, producers
can use it to build proteins and other complex
compounds.
• Decomposers break down these complex
compounds in animal wastes and the bodies of
dead organisms which returns this simple
nitrogen compounds to the soil.
• Nitrogen can cycle from the soil to producers
and then to consumers many times; but bacteria
break down the nitrogen compounds completely.
• These bacteria then release free nitrogen back
into the air which the cycle continues from there.