Biodiversity, conservation and sampling evidence
مُقدَّم| English | المعنى |
|---|---|
| evenness/ˈiːvənnəs/ | التجانس |
| species richness/ˈspiːsiːz ˈrɪtʃnəs/ | تنوع الأنواع |
What would explain this observation?
- A site with many individuals can still be dominated by one species. Abundance, richness and evenness 均匀度 describe different features of biodiversity.
Build the model
- Species richness 物种丰富度 counts species.
- Evenness concerns relative abundance.
- Conservation can protect habitats, populations or genetic diversity; a management judgement must state the conservation goal.
- species richness: The number of species recorded.
- evenness: How evenly individuals are distributed among species.
Two sites have three species each. Which can still differ?
الصعوبة 1/5 · 100 عملة + مكافأة صغيرة عند الإكمال الأول اليوم
Richness counts species only; evenness describes how individuals are shared among them. Two sites can both have three species while one is dominated by a single species and the other is balanced - different evenness, same richness.
Match each technical term to its precise meaning.
الصعوبة 2/5 · 140 عملة + مكافأة صغيرة عند الإكمال الأول اليوم
Use the definitions to distinguish related quantities and processes.
Choose evidence that can test it
- Compare surveys with similar area, effort, season and identification rules.
- A diversity index is meaningful only with its formula and conventions specified.
- Habitat fragmentation can affect movement and gene flow even when total area changes little.
In the lab: Use non-destructive field sampling approved by the school. Identify organisms with a suitable key and record uncertain identifications rather than inventing species. Combine ecological evidence with stakeholder perspectives on land use.
Which two habits make the investigation or model in this case more defensible?
الصعوبة 2/5 · 140 عملة + مكافأة صغيرة عند الإكمال الأول اليوم
Stating the conditions and assumptions lets others repeat the work exactly, and recording the supporting evidence lets them check the conclusion. Hiding disagreeing results removes the evidence that could challenge a wrong conclusion, and one measurement can never establish a wider claim.
Work from known quantities
- Known: site A has counts 8, 1 and 1; site B has 4, 3 and 3.
- Both have richness 3 and total abundance 10.
- The most abundant species occupies 80% in A and 40% in B.
- B is more even under these counts.
Your turn: A survey records 6, 5, 3 and 2 individuals in four species. Find species richness.
A survey records 6, 5, 3 and 2 individuals in four species. Find species richness.
الصعوبة 2/5 · 140 عملة + مكافأة صغيرة عند الإكمال الأول اليوم
The result is 4 species. Known: counts 6, 5, 3 and 2 across four species. Species richness = number of species = 4. Total abundance = 16; evenness would need the distribution, which richness ignores.
Check the conclusion and its limits
- An index cannot by itself explain the cause of a difference.
- A newly recorded species may reflect improved observation rather than a recent ecological arrival.
Not true: A larger total number of individuals always means greater species richness. Richness counts how many species are present, not how many individuals. Ten thousand individuals of one species give richness 1, while ten species with one individual each give richness 10.
- Species richness counts species.
- Compare surveys with similar area, effort, season and identification rules.
- Watch for: an index cannot by itself explain the cause of a difference.
Write from a richness of 5
- A survey records 7, 2, 2, 2 and 1 individuals across five species.
- State the species richness. A larger total of individuals is not greater richness.
Richness counts how many species are present, not how many individuals.
الصعوبة 1/5 · 100 عملة + مكافأة صغيرة عند الإكمال الأول اليوم
True. Richness counts how many species are present, not how many individuals. Ten thousand individuals of one species give richness 1, while ten species with one individual each give richness 10.
The number of species recorded: write the technical term.
الصعوبة 1/5 · 100 عملة + مكافأة صغيرة عند الإكمال الأول اليوم
species richness means The number of species recorded.
A survey records 7, 2, 2, 2 and 1 individuals in five species. What is the species richness, and why is the total of 14 not the richness?
Richness counts species. Abundance counts individuals.
What is the species richness?
الصعوبة 1/5 · 100 عملة + مكافأة صغيرة عند الإكمال الأول اليوم
Five species are recorded. Adding the individuals gives 14, which is abundance, not richness. Other options — 14 individuals (the total count); 7 (the largest single count).