1. Dynamics of Ecosystems

2. Overview
* Sustainability * Cycling of the Elements * Bioaccumulation of toxins in the food chain * Population dynamics * Species Biodiversity * Human actions and effects

3. What is an ecosystem?
Define: is a community of living things (biotic) interacting with non living things (abiotic) in the environment
Biotic: all the living things (plants, animals, bacteria etc.)
Abiotic: all the non-living things (air, water, rocks, weather etc.)
Bill Nye : Ecosystems

4. All living things require some form of energy to survive
Life forms use energy to create the materials (building blocks) and food that they need
If the energy source runs outscan’t make/get the food it needs life form dies

5. Virtually all life on Earth gets its energy
from the light energy of the sun
The sun burns Hydrogen in a process called fusion
Some life forms on Earth can use this energy directly to make food (ie. Plants)
Photosynthesis
Some life forms on Earth can use this energy indirectly by eating other organisms (ie. Animals)
– Cellular Respiration

6. Trophic Levels
The relationships between the organisms that harness the suns energy is analyzed when studying trophic levels
A trophic level represents a specific level of a food chain
a series of organisms that show predator – prey relationships
We will look at 4 distinct levels

8. Producers (1st level)
‘bottom’ of the food chain (Plants)
can use energy from the sun directly
they can make the food they need

9. Consumers (2nd-4th levels)
get energy from what it eats
Fall into 1 of 3 levels:
Primary consumers - eat plants
Ex. Herbivores
Secondary consumers - eat small animals
Ex. Small carnivores
Tertiary/Quarternary consumers - eat larger animals, ‘top’ of the food chain
Ex. Large carnivores

10. ‘Kinds’ of Consumers Herbivore: an organism that eats only plants
Ex. Caterpillars
Carnivore:
an organism that eats only animals
Ex. A robin
Omnivore:
an organism that eats both plants and animals
Ex. Human Beings

11. ‘Kinds’ of Consumers (cont.)
Detritivore/Scavenger:
an organism that eats the bodies of smaller dead animals, dead plant matter and animal dung
Ex. Earthworms
Decomposer:
an organism that consumes any remaining dead plant and animal matter
Ex. Fungi (Mushrooms)
EX. Bacteria

12. FOODCHAIN

14. How do Carbon, Oxygen and Nitrogen get recycled through the ecosystems?