1. Unit 18: Energy and Nutrient Transfer
Section 18.1 Food chains and food webs?
Section 18.2 Pyramids of numbers and biomass
Section 18.3 Energy Flow in Ecosystems
Section 18.4/18.5 Cycles of Matter

2. Organisms and Their Environment
What is an environment?
Area where something lives
Collection of factors that affect an organism
Ecology
the study of interactions that take place between organisms and their environment
What are the different environments on Earth?
Mountains, lakes, rivers, fields, oceans, seas, etc..
Biosphere all living things and all the parts life exists on Earth
11 km in the Ocean to 8 km above the Earth

3. Levels of Organization
Ecosystems with similar climates/organisms
All organism in one set of living conditions
A group of individuals of the same species
One member of a species
Different populations living in one defined area

4. What makes an Environment?
Describe Beihai Lake:
Water, trees, flowers, fish, frogs, birds, people, buildings, garbage, sunlight, open space, etc…
Environmental Factors:
Biotic factors any living part of an environment; animals, plants, bacteria, fungi, etc…
Abiotic factors any non-living part of an environment; sunlight, space, water source, etc…
Both set of factors must stay in balance for the environment to be stable

5. Habitat and Niches
Organisms may not interact with their whole environment:
Habitat the area of an environment that an organism spends its life
Habitats can overlap can cause competition
Is competition a good thing?
Yes, as long as it is under control
To reduce competition, organisms stick to niches specific methods to find food and shelter

6. Energy and Environments
Where does all the energy on Earth come from?
The Sun!
Radiant energy (sunlight) is trapped inside chemical energy by autotrophs
Autotrophs, like plants, bacteria, and algae preform photosynthesis
called Primary Producers
What else is produced by photosynthesis?
O2!
What produces the most O2 on Earth?
Diatoms! Single-celled organisms make 43% of all the O2 in the atmosphere

7. Producers and Consumers
Consumers any organism that must eat another organism to survive
Heterotrophs
Types of Consumers:
Carnivores
eat only other animals
Herbivores
eat only plants, leaves, roots, seeds, and fruit
Omnivores
eat both animals and plants
Scavengers
eat the remains of animals killed by carnivores
Decomposers
break down dead material producing large organic molecules (Detritus)
Detritivores
breakdown detritus

8. Practice Question

9. Moving Energy Around Materials/energy are always Recycled
Law of Conservation of Mass/Energy
Trophic levels:
Primary Producers base of any ecosystem
Primary Consumers eat Primary Producers
Secondary Consumers eat Primary Consumers
Tertiary Consumers eat up to Secondary consumers
Quaternary Consumers eat up to Tertiary Consumers
Decomposers breakdown any dead producers and consumers

10. Food Chains
Food chain map showing how energy/material is transferred through an ecosystem
What is your food chain?
Starting with a primary producer, show the steps leading to you
Ecosystems are never that simple; food chains only show one path energy go follow
Yum!!

11. Food Chains and Food Webs
Food Web network of all food chains possible in the environment
All species inside a food web are important to its stability
What happens if remove just one species?
Puts more pressure on other species
What is missing from this food web?
Decomposers
Why are the decomposers so important?
Recycle nutrients
Quaternary
Consumer
Tertiary
Consumer
Secondary Consumer
Secondary Consumer
Primary Consumer
Primary Consumer
Producer

12. Energy in a Food Web
Ecosystems are divided into levels trophic levels
The First level is always the Primary Producers
Move up trophic levels with each new set of consumers
Ecological Pyramids:
Energy Pyramid
Energy enters through the producers and moves through each level
Only 10% of the energy is one level will move to the next trophic level
What happens to the other 90%?
It is lost in the environment as heat, used by organism, lost as waste
With each level the amount of available energy drops
2-5%