Energy Flow in EcosystemsOctober 2017

Chapter 3, The Biosphere - pg 56-58Write definitions for each of the following words:

1. biosphere2. ecology3. population4. community5. ecosystem6. biome7. biotic factor8. abiotic factor

Vocabulary Introduction

What is Ecology?

Ecology is the scientific study of interactions among and between organisms and their physical environment.

Interactions within the biosphere produce a web of interdependence between organisms and the environments in which they live.

Studying Our Living Planet

The biosphere: the part of the earth in which life exists including land, water , air or atmosphere.

The biosphere extends from about 8 km above Earth’s surface to as far as 11 km below the surface of the ocean.

Levels of Organization

Organizational Level — a term used in Ecological studies to organize organisms and groups of organisms.

Five organizational levels:1. Species 2. Population3. Community4. Ecosystem 5. Biome

Species — organisms with similar anatomical features that can interbreed and produce fertile offspring.

Levels of Organization

Ecological studies may focus on levels of organization that include the following:

Population — a group of individuals of the same species that live in the same geographic area

Levels of Organization

Ecological studies may focus on levels of organization that include the following:

Community — a group of different populations that live together in the same geographic area

Levels of Organization

Ecological studies may focus on levels of organization that include the following:

Ecosystem — collection of all the organisms that live in a particular place, together with their nonliving environment

Levels of Organization

Ecological studies may focus on levels of organization that include the following:

Biome — a group of ecosystems that share similar climates and typical organisms

Levels of Organization

Ecological studies may focus on levels of organization that include the following:

Biosphere — our entire planet, with all its organisms and physical environments

Biotic Factors

A biotic factor is any living part of the environment with which an organism might interact, including animals, plants, mushrooms and bacteria.

Abiotic Factors

An abiotic factor is any nonliving part of the environment, such as sunlight, heat, precipitation, humidity, wind or water currents, soil type, etc.

Biotic and Abiotic Work Together

The difference between abiotic and biotic factors is not always clear. Abiotic factors can be influenced by the activities of organisms and vice versa.

For example, pond muck contains nonliving particles, and also contains mold and decomposing plant material that serve as food for bacteria and fungi.

More Vocabulary

Write the definitions for these words:

1. Primary producer2. Autotrophs3. Heterotrophs4. Consumer5. Carnivore6. Decomposers7. Herbivore8. Omnivore

Trophic Levels - Primary Producers

Primary producers are the first producers of energy-rich compounds that are later used by other organisms.

Trophic Levels - Primary Producers

Sunlight is the original source of almost all energy in most ecosystems

Trophic Levels - Primary Producers

Plants, algae, and certain bacteria can capture energy from sunlight or chemicals and convert it into forms that living cells can use. These organisms are called autotrophs.

Autotrophs are also called primary producers.

Energy from the Sun

The best-known and most common primary producers harness solar energy through the process of photosynthesis.

Trophic Levels - Consumers

Organisms that rely on other organisms for energy and nutrients are called consumers.

Heterotrophs are also called consumers.

Trophic Levels - Consumers

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

Carnivores kill and eat other animals, and include birds, snakes, dogs, cats.

Catching and killing prey can be difficult and requires energy, but meat is rich in nutrients and energy and is easy to digest.

Trophic Levels - Consumers

Herbivores, such as a military macaw, obtain energy and nutrients by eating plant leaves, roots, seeds, or fruits.

Common herbivores include cows, caterpillars, and deer.

Trophic Levels - Consumers

Omnivores are animals whose diets naturally include a variety of different foods that usually include both plants and animals.

Humans, bears, and pigs are omnivores.

Trophic Levels - Decomposers

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

Organisms that obtain nutrients by breaking down dead and decaying plants and animals are called decomposers.

Food Chains

In a food chain, energy moves from the “eaten” to the “eater.” Where it goes from there depends on who eats whom!

Food Chains

Each time an organism eats another organism, an energy transfer occurs.

A food chain is a sequence in which energy is transferred from one organism to the next as each organism eats another organism.

For example the algae the beginning of this food chain are producers…taking energy from the sun.

Food Webs

Ecosystems, however, almost always contain more than one food chain.

A food web shows many feeding relationships that are possible in an ecosystem.

The energy transfer in a food web is more complex than energy transfer in a food chain, because the interaction between many organisms is considered.

Identify three food

chains found

within this food web.

Each chain should have at

least four organisms

If there were no snakes in this food web, would the rabbits and mice still be eaten by another animal?

Decomposers in Food Webs

At the same time, the decomposition process releases nutrients that can be used by primary producers. They break down dead and decaying matter into forms that can be reused by organisms, similar to the way a recycling center works.

Without decomposers, nutrients would remain locked in dead organisms.

Food Chain WS

Food Webs and Disturbances

The effects can be dramatic… For example, all of the animals in this food web depend directly or indirectly on shrimplike animals called krill.

Ecological Pyramids

An ecological pyramid shows the relative number of individual organisms at each trophic level in an ecosystem.

Ecological 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.

Ecological Pyramids

Each step represents a transfer of energy through a food chain or food web.

There is less energy available at the top of the pyramid!

10% RuleOnly about 10% of the energy is available from one trophic level to the next

Trophic Level and Ecological Pyramids WS

What happens to the other 90%?

Organisms expend much of the energy they acquire on life processes, such as respiration, movement, growth, and reproduction.

Most of the remaining energy is released into the environment as heat—a byproduct of these activities.