Dynamics of Ecosystems

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

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 https://www.youtube.com/watch?v=kaW0tr0Keic

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

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

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

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

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

‘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

‘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

FOODCHAIN

How do Carbon, Oxygen and Nitrogen get recycled through the ecosystems? https://www.youtube.com/watch?v=xFE9o-c_pKg