Introduction to Biodiversity
Introduced| English |
|---|
| biodiversity/ˌbaɪəʊdaɪˈvɜːsɪti/ |
| genetic diversity/dʒɪˈnetɪk daɪˈvɜːsɪti/ |
| species richness/ˈspiːsiːz ˈrɪtʃnəs/ |
| resilient/rɪˈsɪlɪənt/ |
The richness of life
- Life on Earth comes in a staggering variety.
- Millions of species, each with its own genes, fill countless habitats.
- This total variety of life is called biodiversity.
- It exists at three connected levels.
Three levels of biodiversity
- Biodiversity 生物多样性 is the variety of life at every scale.
- Genetic diversity 遗传多样性 is the variety of genes within a species.
- Species diversity is the variety of different species in an area.
- Ecosystem diversity is the variety of habitats and ecosystems across a region.
Biodiversity is…
Biodiversity is the variety of life — genes, species, and ecosystems.
Measuring species diversity
- Species richness 物种丰富度 counts how many different species live in an area.
- A rainforest with thousands of species has high richness.
- Diversity also considers how even the species' numbers are.
- More even, more species usually means higher biodiversity.
Species richness means…
Species richness simply counts how many different species live in an area.
The variety of genes within a single species is called ____ diversity.
Genetic diversity is the variety of alleles within a species — the raw material for adapting.
Why it matters
- Higher biodiversity makes an ecosystem more stable and resilient 有韧性的.
- If one species is lost, others can fill its role.
- Diverse ecosystems supply food, medicine, and clean water.
- And genetic diversity gives species the raw material to adapt.
Which level of biodiversity?
Sort each example by the level of biodiversity it describes - genes, species, or whole ecosystems.
Higher biodiversity generally makes an ecosystem more stable and resilient.
With more variety, an ecosystem can better withstand disease, disturbance, and change.
Select all true statements about biodiversity.
Biodiversity is variety, so it is never just one species. The other three are correct.
Biodiversity is more than just counting species. Genetic diversity within a species matters too: a crop with little genetic variety can be wiped out by a single new disease, while a genetically diverse population can survive it. Look at all three levels, not just the species count.
Why genetic diversity saved a crop:
- In the 1970s a disease attacked the world's rice, and most varieties were vulnerable.
- Scientists found one wild rice with a rare resistance gene — an example of genetic diversity.
- Breeding that gene in saved the crop. Without that hidden variety, the harvest could have failed.
Biodiversity is the variety of life at three levels: genetic (genes within a species), species (species richness counts them), and ecosystem (variety of habitats). Higher biodiversity makes ecosystems more resilient and supplies food, medicine, and the genes species need to adapt.