| A | B |
|---|
| the predictable and orderly changes that occur in nature | ecological succession |
| the ____________of an area can determine how severely a disturbance affects it | topography |
| Lichen are often the first plants or ------------ to grow in a barren land | pioneer species |
| one stage of succession | sere |
| occurs after a new substrate is formed | primary succession |
| brod leaved, deciduous trees | hardwood |
| evergreens or conifers | softwood |
| hardened lava and bare rock are examples of | substrate |
| the study of relationships between organisms and their environment | ecology |
| in both primary and secondary successionk, plants begin to _____________ an area | colonize |
| plant life in an area | vegetation |
| ___________ succession occurs when the soil base has been completely destroyed | primary succession |
| occurs after a disturbance in which the soil base is not completely destroyed. | secondary succession |
| how is soil formed in primary succession | Pioneer species such as lichen, moss and weeds begin to grow on the new substrate. They break down the rocks. when they die, they decompose and become organic matter and mixed in with the rock. A rich soil base then forms. |
| Why aren't forest fires always considered bad? | Undergrowth in forests becomes too thick. Fires clear out the unwanted brush. Fire also stimulates the regrowth of certain poants such as sagebrush, aspen and willows. The intense heat opens lodgepole pine cones, releasing the seeds in side. Fires help bring balance back to an ecosystem |
| Explain why the eruuption of Mount Saint Helens could be an example of both primary and secondary succession | The areas that were affected by lava had to begin with a new substrate, causing primary succession to occur. The areas in which seeds and roots survived are examples of seconary succession because the soil base was not destroyed |
| Why are glacial retreats so devastating to the land? | They scour the earth and leave nothing but bare rock behind |
| Is a glacial retreat considered primary or secondary succession | primary |
| 4 stages of glacial retreat succession | Nothing but bare rock is left. The rock is broken down by pioneer species like lichens and moss that colonize the area. Then vegetation such as wildflowers and shrubs grow. Finally a mature forest of softwood and hardwood trees may develop. |
