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

2. 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)

3. 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?

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

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

6. 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

7. 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

8. 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