Back to AI Flashcard MakerAnatomy and Physiology /A-level Biology - The Effect of Biotic and Abiotic Factors on Populations
A-level Biology - The Effect of Biotic and Abiotic Factors on Populations
This flashcard deck covers key concepts related to biotic and abiotic factors affecting populations, focusing on succession, conservation, and experimental methods in ecology.
Give an example where secondary succession may occur
e.g. after forest fire or deforestation
Tap or swipe ↕ to flip
Swipe ←→Navigate
1/21
Key Terms
Term
Definition
Give an example where secondary succession may occur
e.g. after forest fire or deforestation
What happens at the start of primary succession?
Pioneer species colonise new land surface e.g. Seeds and spores blown by wind & begin to grow
Primary Succession Why is it at first only the pioneer species grow?
Abiotic conditions are hostile (e.g. no soil to retain water) & only pioneer species = specially adapted to cope with harsh conditions
Primary Succession Describe how the pioneer species change the abiotic conditions
Change in environment They die and micro-organism decompose dead organic material (humus) Forms basic soil
Primary Succession What is the result after a basic, thin soil has formed?
Makes conditions less hostile (e.g. basic soil retains water) ∴ new species with different adaptations can grow Then die and decomposed adding more hu...
Primary Succession What happens at each stage (competition wise)?
Different plants and animals that are better adapted for improved conditions move in & out-compete plants and animals already there & become dominant ...
Related Flashcard Decks
Study Tips
- Press F to enter focus mode for distraction-free studying
- Review cards regularly to improve retention
- Try to recall the answer before flipping the card
- Share this deck with friends to study together
| Term | Definition |
|---|---|
Give an example where secondary succession may occur | e.g. after forest fire or deforestation |
What happens at the start of primary succession? | Pioneer species colonise new land surface e.g. Seeds and spores blown by wind & begin to grow |
Primary Succession Why is it at first only the pioneer species grow? | Abiotic conditions are hostile (e.g. no soil to retain water) & only pioneer species = specially adapted to cope with harsh conditions |
Primary Succession Describe how the pioneer species change the abiotic conditions | Change in environment They die and micro-organism decompose dead organic material (humus) Forms basic soil |
Primary Succession What is the result after a basic, thin soil has formed? | Makes conditions less hostile (e.g. basic soil retains water) ∴ new species with different adaptations can grow Then die and decomposed adding more humus = makes soil deeper and richer in minerals ∴ larger plants (shrubs) can grow & more water retained |
Primary Succession What happens at each stage (competition wise)? | Different plants and animals that are better adapted for improved conditions move in & out-compete plants and animals already there & become dominant species in ecosystem |
Primary Succession As succession goes on, increases | biodiversity |
Primary Succession Name and describe the final stage | Climax community Ecosystem is supporting the largest and most complex community of plants and animals it can Won't change much = in steady state |
Secondary succession happens in same way but at a ___ stage | later Pioneer species are larger plants e.g. shrubs |
What is meant by plagioclimax? | When succession is stopped artificially (e.g. by humans), climax community its called plagioclimax |
How are ecosystems conserved? | Succession is prevented to preserve an ecosystem in its current stage of succession |
Name 2 ways to manage succession to conserve moorland ecosystem | Animals are allowed to graze on land Managed fires |
Describe how allowing animals to graze on land can manage succession | (Similar to mowing) = growing points of shrubs and trees eaten = stops them establishing themselves & keeps vegetation low |
Describe how having managed fires can manage succession | After fires = secondary succession will occur & species that grow back first (pioneer species) are being conserved Larger species will take longer to grow back & will be removed when moor is burnt |
Define Conservation | Protection and management of species and habitats in sustainable way |
Name and describe 4 examples of conservation techniques | Protected areas (e.g national parks & nature reserves) protects habitats Restrict urban development, industrial development & farming Using seedbanks to conserve plants They're stores of lots of seeds from lots of different plant species If they become extinct = can be replanted Fishing quotas Limits to amount of a fish species fishermen can catch Reduces no. caught & killed Endangered species can be bred in captivity to increase their numbers & then returned to wild |
Describe how you would investigate the effect of competition on seedling growth | Divide base of Petri dish into 8 equal segments. Do this for 5 dishes. Place filter paper in each Petri dish & same amount of water (just enough so the paper is wet) In 1st Petri dish, place 1 seed in the middle of each segment Continue placing seeds in the rest of the Petri dishes, increasing the number of seeds in each segment each time by 1 Place lids on Petri dishes Put all dishes together in dark cupboard Observe the seeds at same time each day & count how many seeds have germinated After 3 days, remove seedlings & measure the growth of shoot and root Record results in table & carry out statistical test to see if there's a significant difference in germination and initial growth in the seedlings at different densities of sowing |
When investigating the effect of competition on seedling growth, name 4 precautions you should take | Wash hands Use boiled water Don’t handle seeds and there should be minimal handling of the inside of Petri dishes and filter papers Petri dishes should be clean/sterile All to destroy/prevent the spread of micro-organisms |
When using the mark-release-recapture method, why is it important that the samples contain as many organisms as possible? (2) | More organisms in sample = improve accuracy of estimate ∵ calculation assumes a constant ratio between total number of marked and unmarked individuals |
What is meant by uniformly distributed (1)? | Same number (of organisms) in each region / (organisms) equally spread |
The pioneer plants had seeds that germinate better when the temperature fluctuates. Explain the advantage of this to these pioneer plants. (2) | Bare soil temperatures fluctuate More bare soil, early / at start of succession / when few plants |