Succession-Population Density

Building a ecosystem and how crowded it gets.

Ecological Succession

• Ecosystems are always changing due to natural and human disturbances. As things change old inhabitants die out and new organisms move in.

• When these changes are done in a predictable pattern it is called ecological succession.

Ecological Succession

• What would happen to your yard if you didn’t mow it for a month?

• For a year?

• For ten years?

Ecological Succession

Ecological Succession

• On land when succession occurs where there is no soil (after a volcano erupts or a glacier melts) it is called primary succession.

Ecological Succession

• On land when succession occurs where there is no soil (after a volcano erupts or a glacier melts) it is called primary succession.

Ecological Succession

• The first species to populate these areas are called pioneer species.

• (often lichen)

Ecological Succession

• Restoration of an ecosystem to its original condition after a major disturbance (fire, farming) is called secondary succession.

• What do you think will happen to area of the BWCA that suffered the massive blown down from straight line winds?

• Will it ever return to the state it was before the storm came through?

Population Density

• Population density = number of individuals per unit area

Population Density

• All of the people who have birthdays in October move to the south side of the room. Everyone else move to the north side of the room.

Population Density

• All of the people who have birthdays in October move to the south side of the room. Everyone else move to the north side of the room.

• North side is considered high density

• South side is considered low density

Population Density

• Which side of the room would have to compete more for resources?

• How would this affect an organism?

Population Density

• Lets allow the summer birthdays to immigrate into the south side.

Population Density

• Lets allow the summer birthdays to immigrate into the south side.

• Immigration is the movement of more individuals into an area

• Emigration is the movement of individuals out of an area.