BISC 204 Study Guide - Final Guide: Devonian, Glacial Motion, Secondary Succession

• School: Simon Fraser University
• Department: Biological Sciences
• Course: BISC 204
• Professor: Wendy Palen

Document Summary

Ecological systems are rarely found in equilibrium conditions, because they are always continuously changing. Disturbances prevent ecological systems from remaining static over time. Disturbances: physical, biological not always catastrophic, can be subtle. Common examples include: fire, flooding, volcanoes, glacial activity, seasonal changes, herbivory etc. Beaver dam: flooding an area to create a flood plain area that will kill the growing trees that live in that area that they eat and then use for their dam. They can change a pond or stream into a decent sized wetland or lake. Salmon: females move their bodies to kick up sediment at the bottom, if there are lots of salmon this could be a big disturbance to algae and invertebrates on the riverbed). Succession is the term describing the predictable sequence of changes in species composition of communities following disturbance. Progresses from a pioneer species to a climax community. Follows (in terms of plant life): annual plants perennial plants/grasses shrubs.