Transcript Biotic Factors

Ch 36 Energy in
Ecosystems
36.1 Food Chains
& Food Webs
34.1 Biotic and Abiotic Factors
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What are biotic and abiotic factors?
The biological influences on organisms are called
biotic factors. Physical components of an ecosystem are
called abiotic factors.
Biotic Factors
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A biotic factor is any living part of the environment
with which an organism might interact, including
animals, plants, mushrooms and bacteria.
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Biotic factors relating to a bullfrog might include
algae it eats as a tadpole, the herons that eat
bullfrogs, and other species competing for food or
space.
Abiotic Factors
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An abiotic factor is any nonliving part of the
environment, such as sunlight, heat, precipitation,
humidity, wind or water currents, soil type, etc.
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For example, a bullfrog could be affected by abiotic
factors such as water availability, temperature, and
humidity.
Biotic and Abiotic Factors
Together
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The difference between abiotic and biotic factors is
not always clear. Abiotic factors can be influenced by
the activities of organisms and vice versa.
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For example, pond muck contains nonliving
particles, and also contains mold and decomposing
plant material that serve as food for bacteria and
fungi.
Biotic and Abiotic Factors
Together
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In addition, trees and shrubs affect the amount of
sunlight the shoreline receives, the range of
temperatures it experiences, the humidity of the air,
and even the chemical conditions of the soil.
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A dynamic mix of biotic and abiotic factors shapes
every environment.
34.1 The Study of Ecology
 Ecology: interactions among organisms and their
environment
 Biotic Factors: Living things found in the
environments (bacteria, protists, fungi, animals, plants).
 Abiotic Factors: the nonliving physical and chemical
conditions (soil, water, air, sun….).
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Organism- Smallest unit of ecological study.
Ex. Blue Sweet lip fish
Ecologists might ask, “How do Blue Sweet lip fish adapt to the challenges posed by the environment?”
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Population- a group of individual species living in a particular area .
Ex. A group of Blue Sweet lip fish
Ecologists might ask, “What factors limit the numbers of sweet lip fish living around this reef?”
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Communities- All of the organisms that live in a particular area
make up a community.
Ex. Coral reef is home to many living things including fish, coral animals, microscopic algae….
Ecologists might ask, “How might a disease that strikes the coral animals affect the other species in the community?”
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Ecosystems- includes the living (biotic factors) and the
nonliving (abiotic factors) things in an area.
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Reef’s many living species, the temperature of the water, and the amount of sunlight
An ecologist might ask, “ How does nitrogen move within the reef ecosystem?”
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Biosphere- broadest level of ecological study.
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Sum of all Earth’s ecosystems.
Envelope of air, water, land that supports and includes all life.
Biosphere is a closed system, this means that chemicals in the biosphere’s living and nonliving things mostly
come from within the system, not from the outside.
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An ecologist would study global issues, and the effects of climate change on living things.
Patchiness of the Biosphere
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Biosphere is not uniform, it is unevenly spread out.
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Biosphere is like a quilt of many different environments (land,
oceans, lakes, ice)
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You can find an uneven distribution of biomes on a continent.
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You can find patches of woods, fresh water, and marshes in a smaller
area of wilderness.
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Patchiness creates a number of different habitats.
Habitat: specific environment in which organisms live.
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All habitats have different abiotic and biotic factors.
Key Abiotic FactorsHow it affects animals/ plants
1.)Sunlight- provides light and warmth, powers photosynthesis.
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Canopy of forest gets more light than the forest floor.
Sea floor gets less light than the surface of the ocean
2.)Water- essential for all life. (we are 70% water)
3.)Temperature- most life exists between a narrow range of temperatures.
(0 50 °C)
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Few organisms can maintain an active metabolism below 0 °C
Most organisms enzymes are denatured above 50°C
Key Abiotic FactorsHow it affects animals/ plants
4.) Soil- the product of abiotic forces (such as ice, rain, and wind) and the
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actions of the living things (microorganisms, plants and earthworms) on
the rocks and minerals of the earth’s crust.
Chemical makeup of the soil and rock affect the types of plants that grow
there.
Dry/ nutrient-poor soil = dominated by little bluestem grasses
5.) Wind- it can affect the distribution and organisms in several ways.
It moves clouds and rain over the Earth’s surface.
 Stirs up water in ponds, lakes, and streams.
 Creates currents that bring up nutrients from the bottom.
 Helps to disperse pollen and seeds.
6.) Sever Disturbances- fires, hurricanes, tornadoes, droughts, floods,
and volcanic eruptions.
 Some are infrequent so organisms have not adapted to these
disturbances.
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36.1 Feeding relationships
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Energy flow through ecosystems begins with producers.
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Energy flows in 1 direction
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Nutrients cycle
Consumers (Heterotrophs)
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Herbivores
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Omnivores
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Eat only plants and fungi
Eat both plants/fungi and animals
Carnivores
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Eat only animals
Detrivores/ Decomposers
consumers that feed on detritus, the wastes and remains of
dead organisms.
 Nutrients returned back to the soil
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Producers (Autotrophs)
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Photosynthetic organisms
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Capture energy from sunlight, CO2 and H2O
Most producers are photosynthetic
Chemosynthetic or chemoautotrophs organisms
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Capture energy from chemical compounds in the
surroundings (DEEP SEA HYDROTHERMAL VENTS)
 Energy is lost in each step up a food chain
 Only 10 % of the energy from one level on the food
chain is available to the next level (90% lost as heat)
FOOD CHAINS
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The pathway of food transfer from one trophic level to another is
called a food chain.
In all food chains, producers make up the trophic level that
supports all other levels.
What’s missing from this food chain?
FOOD WEBS
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Consumers usually have many food sources.
A hawk can eat a small bird, fish, mouse...
The pattern made by interconnected and branching food chains
is a food web.
Food Webs
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Many consumers and
decomposers have more
than 1 food source
Movement of energy
occurs in complex webs
rather than in simple
chains
A food web shows a complex network
of feeding relationships.
A food web shows a complex network
of feeding relationships.
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An organism may have multiple feeding relationships in an ecosystem.
A food web emphasizes complicated feeding relationships and energy flow
in an ecosystem.
Trophic Levels
Each of the feeding organisms represents a trophic level in the
ecosystem. Both energy and chemicals move from one organism to the next as organisms feed.
Producers/Primary Producers
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Autotrophs (Photosynthesizers, Chemosynthetic organisms)
Primary consumers- 1st level
 Herbivores and omnivores that eat producers
Secondary consumers- 2nd level
 Carnivores and omnivores that eat herbivores-
primary consumer
Tertiary consumers- 3rd level
 Carnivore eats another carnivore- secondary consumer
Quaternary Consumers- 4th level
eats another carnivore-
tertiary consumers
Figure 36-2
Each of these food chains includes five trophic levels. The arrows indicate the direction of food transfer
between trophic levels.
A Simplified Food Web?
36.1 Objectives p. 788
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Contrast the flow of energy and chemicals in
ecosystems
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Explain how trophic levels relate to food chains and
food webs.
Thumbs Up?
Thumbs Down?
36.1 Concept Check p. 791
1.
How are the movement of energy and the
movement of chemicals in ecosystems different?
2. In the following food chain, identify the trophic
levels:
Berriesmouse owl
3.
fig. 36-3 identify a food chain w/ 3 trophic levels