Ecology: Flow of Energy

Ms. Selman

ObjectivesA. 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; andG.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”.

HerbivoresSome 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

grass

mice

berriesseeds

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.