Biodiversity, conservation and sampling evidence
הוצג| English | משמעות |
|---|---|
| evenness/ˈiːvənnəs/ | התפלגות אחידה |
| species richness/ˈspiːsiːz ˈrɪtʃnəs/ | עושר מינים |
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?
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
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.
רמת קושי 2/5 · 140 מטבעות + בונוס קטן בהשלמה הראשונה היום
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?
רמת קושי 2/5 · 140 מטבעות + בונוס קטן בהשלמה הראשונה היום
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.
רמת קושי 2/5 · 140 מטבעות + בונוס קטן בהשלמה הראשונה היום
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 6
- Counts are 5, 2, 2, 1, 1 and 1.
- Find the species richness. Say why the total of 12 is not the richness.
Richness counts how many species are present, not how many individuals.
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
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.
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
species richness means The number of species recorded.
A survey records counts 5, 2, 2, 1, 1 and 1. What is the species richness, and why is the total number of individuals a different quantity?
Six counts mean six species. Adding them gives 12 individuals, which is not the richness.
What is the species richness?
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
There are 6 recorded species. The sum 12 counts individuals. Other options — 4 species (the earlier calculation's result for counts 6, 5, 3 and 2); 12 (the total number of individuals).