Unit: Ecological Biomes and Human Impacts on the Environment

Lesson 1: Introduction to

Ecosystems, Trophic Levels, and Energy

Transfer

What does this word mean to you?

Ecosystem

List some of the features that are found within each of the ecosystems on the next slide.

Afterwards, try and determine what ecosystem is represented by the picture.

1. 2.

3. 5.

4.

6.

What were some of the components you included in your list?

Could you correctly identify any of the ecosystems?

Coming back to the term…“Ecosystem” Focus on the 2nd part of the word,

“system” What does it mean to think about

ecosystem in terms of a system? Are there any components you

can add to your lists?

1. 2.

3. 5.

4.

6.

MarineTundra

Forest

Prairie

Desert

Rain Forest

An Ecosystem contains both abiotic and biotic factors:

Abiotic factors are nonliving things that influence an organisms. They can be organized into several broad categories: energy, nonliving matter, and living space.

Biotic factors include all forms of life. Broad categories include: plants, animals, bacteria, fungi, viruses, other parasitic organisms.

Unit Project Requirements Form groups of 3 or 4 Determine what ecosystem you want to

research Will be adding content to project as it is covered

in class. After each class period, your group will be expected to research specific content related to your ecosystem and bring it to class the following day.

As a group, you will present project to the rest of the class and each group member will be held accountable for knowing their ecosystem.

Energy in an Ecosystem

Ecosystems are not unchanging Organisms within it are growing, reproducing, dying, and decaying

Must have a continuous input of energy to retain its stability

Where is the source of

energy for this ecosystem?

The only significant source of energy for most ecosystems is sunlight!

Energy flow through Ecoysystems Producers are the only organisms

that are capable of trapping solar energy through process of photosynthesis.

Energy is stored in the form of chemical bonds and is transferred to other organisms when the producers are eaten.

Trophic Levels Each step in the flow of energy through

an ecosystem is known as a trophic level Producers 1st level Herbivores 2nd level Carnivores eating herbivores 3rd

level Carnivores eating carnivores 4th

level Omnivores, parasites, &

scavengers vary

Illustration of trophic levels

Energy Relationships1st law of thermodynamics states that:

energy can be transformed (changed from one form to another), but cannot be created or destroyed.

2nd law of thermodynamics states that:Whenever energy is converted from one form to

another, some of the energy is converted to a nonuseful form (typically low-quality heat).

Thus, when energy passes from one trophic level to the next, there is less useful energy with each

successive trophic level.

Energy dissipated to the surroundings and warms the air, water, or soil. In addition, organisms use some of the energy to maintain their own life processes such as chewing food, defending nests, walking to waterholes, or producing and raising offspring.

http://www.mhhe.com/biosci/pae/environmentalscience/enger8e/animations/energy_conversion.mov

Agricultural benefit

A herbivore may not be able to digest all of what it does it and therefore must excrete the material as waste.

Dung Beetles feed partly or exclusively on feces, primarily herbivore feces.

Benefits: remarkable role in agriculture as they improve nutrient recycling and soil structure!

Practice your understanding:

Where is the most energy in this ecosystem?

The most energy is found at the bottom of a food chain

How much energy is lost?1,000,000

units of solar energy

1% available for plants

10,000 units

90% lost

90% lost

1,000 units

100 units

10 units

90% lost

Make a Prediction… Since it is difficult to measure the

amount of energy contained in each trophic level, how do you think ecologists might measure and account for this loss of energy and the amount of energy contained in each trophic level?

Biomass Pyramid

Practice your understanding:

Project Requirement

Use the biomass information your group found for your particular biome in order to construct a biomass pyramid. The pyramid should include both the number and types of organisms found at each level.