Energy Flow In Ecosystems

ENERGY FLOW

• All Life on Earth needs energy for cell processes.

• For most life on Earth, sunlight is the ultimate energy source.

• Organisms get energy by using light or chemical energy to make food or by eating other organisms

PRODUCERS• Producers change the energy available in their

environment into food energy. • They make their own food (autotrophs)

• Plants, algae, and some microorganisms use a chemical process called photosynthesis to change light energy into chemical energy (Glucose)

• This process adds oxygen to the atmosphere and removes carbon dioxide.

Producers That Use Sunlight

cyanobacteria

Algal colony

phytoplankton

Plants & Trees

Life Without Light• Biologists have discovered thriving

ecosystems around volcanic vents in total darkness on the deep ocean floor.

• Deep-sea ecosystems depend on primary producers that harness chemical energy from inorganic molecules such as hydrogen sulfide.

• The use of chemical energy to produce carbohydrates is called chemosynthesis. giant tube worms

live in symbiosis with the chemosynthetic bacteria

Consumers• Consumers- organisms that cannot make their own • food and get their energy from eating other organisms.

(heterotrophs)

• Consumers use the chemical process of cellular respiration to break down food in the presence of oxygen to produce energy.

Types of Consumers

• Consumers are classified by the ways in which they acquire energy and nutrients.

• Herbivores-obtain energy and nutrients by eating plant leaves, roots, seeds, or fruits.

Types of Consumers

Carnivores- kill and eat other consumers

Types of ConsumersOmnivores- consume a variety of different foods that usually include both plants and animals. Humans, bears, and pigs are omnivores.

Types of ConsumersScavangers- animals that consume the carcasses of other animals that have been killed by predators or have died of other causes.

Types of Consumers

• Decomposers-such as bacteria and fungi, feed by chemically breaking down organic matter.

• The decay caused by decomposers is part of the process that produces detritus—small pieces of dead and decaying plant and animal remains.

• Decomposers that live on, and in, detritus particles are called Detrivores.• They feed on detritus particles,

often chewing or grinding them into smaller pieces. Ex: giant earthworms

Food Chains• Each time one organism eats another organism, a

transfer of energy occurs

• Food chain- models how energy flows in an ecosystem through feeding relationships.

• Food chains can vary in length. An example from the Everglades is

shown.

Food Webs Food web- links all of the food chains in an ecosystem together.

• It shows many feeding relationships that are possible in an ecosystem

An example of a food web in the Everglades is shown.

Trophic Levels and Energy Pyramids

Each step in a food chain or food web is called a trophic level.

Primary producers always make up the first trophic level.

Various consumers occupy every other level

Energy pyramids- show the amount of food energy available at each trophic level

Trophic Levels and Energy Pyramids

Energy pyramids- show the amount of food energy available at each trophic level

Each time energy is transferred from one organism to another, lost and less energy is available at the next trophic level.

Trophic Levels and Energy Pyramids

Energy is lost: as heat through cellular respiration.

o this energy is used to carry out functions of living things such as producing new cells, regulation of body temperature, and moving around

Trophic Levels and Energy PyramidsThe remaining 10% of the energy becomes part of the organism’s body and is stored in its molecules.

This 10% is available to the next trophic level when one organism consumes another organism