Ecology: Flow of Energy
Ms. Selman
Objectives
A. Explain the ecological levels of organization in the
biosphere;
B. Describe the parts and players in an ecosystem;
C. Arrange components of a food chain according to energy
flow;
D. Create a food web;
E. Compare the quantity of energy in the steps of an energy
pyramid;
F. Use diagrams to trace and explain the movement of matter
through cycles in an ecosystem; and
G.Explain the concept of a limiting factor as it relates to
water and nutrients.
A. Explain the ecological levels of organization in
the biosphere;
• An ecosystem refers to all the animals and
plants found in one place, and the way they
all live together.
• Different plants and animals live in different
ecosystems.
• Different ecosystems can be close together.
• Some animals belong to several
ecosystems.
Levels of Organization
• The biosphere contains a complex set of
interaction between organisms
• Species/Individual: a group of organisms so
similar they can reproduce
• Populations: a group of the same species
that live in the same area
Levels of Organization
• Communities: groups of different
populations that live in the same area
• Ecosystem: organisms and the non living
environment in a particular place
• Biome: a group of ecosystems that share
the same climate, and dominant
communities (desert)
B. Arrange components of a food chain according to
energy flow;
• All living things (organisms) need food
(nourishment) to live.
• Living things in an ecosystem depend on each
other for food.
Carnivores
Some animals, like the kingfisher, eat
only other animals. These animals are
called “carnivores”.
Herbivores
Some animals do not eat other animals.
They survive on plants and are known as
“herbivores”.
Omnivores
• Some animals, like us, eat both plants
and animals.
• These animals are called “omnivores”.
Consumers
• “Consume” means “eat”.
• Animals are consumers because they
“eat” (consume) food provided by plants
or other animals. (heterotrophs)
Producers
• Plants are living organisms. They need
nourishment to survive.
• But…
• Plants do not eat other plants or
animals.
• Plants are called producers, because
they make their own food inside
themselves. (autotrophs)
Predator
A predator eats other animals.
Cats eat fish.
So do bears!
Predator
• People are predators too!
Prey
Any animal which is hunted and killed by
another animal for food is prey.
Predator
Prey
Predators and Prey
Some animals are predators, some are prey - some are
both.
The predator eats the prey, and the prey gets eaten
by the predator.
Food Chains
A food chain shows what is eaten.
The lettuce is eaten by the
rabbit.
Food chains always start
with a plant.
The lettuce is eaten by the slug, the slug is eaten by the
bird.
Food Chains - a Reminder
• A food chain shows which animals eat
other animals or plants.
• Plants don’t eat things.
• A food chain starts with what gets
eaten and the arrows point towards
what does the eating.
• Food chains only go in one direction.
Where do the arrows point?
Food Webs
• In the wild, animals may eat more than
one thing, so they belong to more than
one food chain.
• To get the food they need, small
herbivores may eat lots of different
plants, and carnivores may eat many
different animals.
Food Webs
We can show this by using a food web, which is just a more
complicated version of a food chain.
owl
fox
rabbits
mice
grass
seeds
berries
Breaking the Chain
• Organisms living in a habitat depend on
each other.
• If one part of a food chain dies out or
is greatly reduced, the consumers have
to find alternative food, move away, or
starve.
• This then affects more consumers in
the same way.
C. Create a food web;
• Chose an ecosystem to work from
• Include at least 12 organisms, 4 autotrophs, 1
decomposer
• Organize your drawing into trophic levels
• Be sure to draw all interactions that are
happening between organisms
• Ideas: Forest, desert, Utah Mountains, Ocean,
Jungle, Savanna
E. Compare the quantity of energy in the steps of an
energy pyramid;
• Ecological pyramid: a diagram that shows
the amounts of energy or matter in each
trophic level of a food chain or food web
• Top level consumers 1% of energy
• First level consumers 10% of energy
• Producers produce 100% of
available energy
F. Use diagrams to trace and explain the movement of
matter through cycles in an ecosystem; and
• Unlike the one way flow of energy, matter is
recycled within and between ecosystems
• Biogeochemical cycles: elements,
chemicals, and other matter is passed
through the biosphere
The Water Cycle
• All living things require water
• New water is not created, it moves between the
oceans, atmosphere and land
• Evaporation: process by which water changes
from liquid to gas
• Transpiration: when water evaporates from the
leaves of plants
The Water Cycle
The Carbon Cycle
• Carbon is the key ingredient in living tissue
• CO2 is important part of the atmosphere
• CO2 is taken in and used by plants, and
release by animals and plants
The Carbon Cycle
• Has four main types of processes:
– Biological: photosynthesis, respiration, and
decomposition, take up and relase CO2 and
oxygen
– Geochemical: such as erosion and volcanic
activity, release carbon dioxide into the
atmosphere and oceans
The Carbon Cycle
• Mixed Biochemical processes, such as
burial and decomposition of dead
organisms and their conversion under
pressure into coal and petroleum, store
carbon underground
• Human activities such as mining, cutting
and burning forests, releases CO2 into the
atmosphere
The Carbon Cycle
The Nitrogen Cycle
• All organisms require nitrogen to make amino
acids, which form proteins
• Nitrogen makes up 78% of the earth’s
atmosphere
• Nitrogen fixation: process where a bacteria on
the roots of legumes (peas, beans, alfalfa)
converts nitrogen gas into usable ammonia
• Denitrification: when soil bacteria convert
nitrates into nitrogen gas.
The Nitrogen Cycle
The Phosphorus Cycle
• Phosphorus is essential for living
organisms because it is part of DNA and
RNA
• Phosphorus does not become part of the
atmosphere
• Released as rocks and sediments wear
down
• As it dissolves, it is used by organisms
The Phosphorus Cycle
G. Explain the concept of a limiting factor as it relates to
water and nutrients.
• Primary Productivity: the rate at which
organic matter is created by producers
• Limiting nutrient: when an ecosystem is
limited by a single nutrient that is scarce or
cycles slowly
• Ex. Algal bloom: when a limited nutrient
becomes abundant, not enough
consumers to eat it.