unit 7 concept 5 Flashcards
(39 cards)
What is ecological succession?
A series of changes that occur over time in an ecosystem, where one community of organisms is gradually replaced by another.
What is a climax community?
The final stage of succession, characterized by a stable, mature community with a complex structure.
What initiates primary succession?
It begins on surfaces where no soil exists, such as bare rock after a volcanic eruption or glacier retreat.
What are pioneer species?
The first organisms to colonize an empty or disturbed area, often hardy and capable of surviving harsh conditions.
List the stages of primary succession.
- Pioneer species arrive
- Lichens break down rock
- Small plants grow
- Grasses and wildflowers move in
- Shrubs and juvenile trees appear
- Climax community forms
How does primary succession differ from secondary succession?
Primary succession starts from lifeless surfaces with no soil, while secondary succession occurs in areas where soil and some life remain after a disturbance.
What is the role of pioneer species in succession?
They modify the environment, create soil, and add nutrients, making it possible for more complex species to thrive.
True or False: Secondary succession occurs more quickly than primary succession.
True
What can trigger secondary succession?
- Natural disturbances (e.g., forest fire, flood)
- Human-made disturbances (e.g., logging, abandoned farmland)
What is a common example of pioneer species in secondary succession?
Fast-growing grasses, weeds, or wildflowers.
What characterizes a climax community?
Stable, long-lasting, complex, and adapted to the local climate.
Fill in the blank: The first organisms to appear in primary succession are called _______.
[pioneer species]
What adaptations do pioneer species have?
- Hardy and tolerant
- Rapid growth and reproduction
- Short life cycle
- Sun lovers
- Soil builders
What happens to pioneer species as succession progresses?
They are often outcompeted by taller or more shade-tolerant plants.
Describe the conditions that allow pioneer species to thrive.
They can survive in harsh, nutrient-poor conditions and often grow in bright sunlight.
What is the expected outcome of secondary succession after a disturbance?
The ecosystem may mature into a community similar to what was there before the disturbance.
What is one reason secondary succession can be faster than primary succession?
The presence of existing soil and often dormant seeds allows for quicker recovery.
True or False: Climax communities are always identical to the original community before a disturbance.
False
What role do animals play in ecological succession?
They gradually appear as plant communities establish, supporting a complex food web.
What is a climax community?
A stable ecosystem, such as a forest, that remains dominant unless disrupted by changes like climate shifts or disturbances.
What type of plants dominate in a climax community?
Shade-tolerant, slow-growing plants, such as shade-loving trees like beech or hemlock.
How do pioneer species differ from climax community species?
Pioneer species are the first to establish, grow rapidly, are short-lived, and thrive in bright sunlight, while climax species are long-lived and can tolerate shade.
What happens to community composition after disturbances?
Minor disturbances allow some pioneer species to enter in small patches, while major disturbances may require primary or secondary succession to recover.
What is the difference between primary and secondary succession?
Primary succession starts in an area with no soil and no prior life, whereas secondary succession begins in an area that has soil and was previously inhabited but disturbed.
