Warm-up: April 8th What is homeostasis? What happened to the population numbers when equilibrium was met? Which tropic level is always the largest?

Ecological Succession A series of predictable changes that occurs in a community over time Occurs through slow changes after a sudden natural disaster (forest fire, volcano, glacier retreat) or from human activity (clearing of a forest)

Primary Succession Occurs on surfaces where no soil exists (after a volcanic eruption or after a glacier retreats) First species to populate this area is called a pioneer species – usually lichens. Why are lichens usually pioneer species?

Secondary Succession Occurs after a disturbance that destroys a community without destroying the soil (wildfire, disease, clearing of a forest)

Succession in a Marine Ecosystem Also known as a “whale fall” Occurs in 3 stages

Marine Succession Stage 1 Begins when a large whale dies and sinks to the ocean floor Attracts scavengers and decomposers (hagfish, sharks, crabs, shrimp), which eat the soft tissue

Marine Succession Stage 2 After 1 year, most of the soft tissue has been eaten Decomposition of the body enriches the sediment with nutrients, which attracts fish, crabs, and many marine snails and worms

Marine Succession Stage 3 Begins only when the skeleton remains Bacteria decompose the oils inside the bones The bacteria support a community of mussels, marine snails, marine worms, crabs, and clams