Term
| How do humans depend on biodiversity? |
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Definition
| Humans depend on biodiversity for the products that wild species provide and for ecosystem services that protect the quality of the abiotic environment |
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Term
| On what three levels do biologists recognize and analyze biodiversity? |
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Definition
1) genetic diversity
2) species diversity
3) ecosystem diversity |
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Term
| What is genetic diversity? |
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Definition
| Genetic diversity is the total genetic information contained within all individuals of the species, measured as the number and relative frequency of all alleles present in the species |
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Term
| What is species diversity? |
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Definition
| Species diversity is the variety of lifeforms on earth, measured as the number and relative frequency of species in a particular region |
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Term
| What is ecosystem diversity? |
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Definition
| Ecosystem diversity is the variety of biotic communities in a region, along with abiotic components such as soil, water and nutrients |
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Term
| What is taxonomic diversity? |
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Definition
| Taxonomic diversity encompasses the evolutionary relationships among species present in a region. Some lineages on the tree of life are species rich, others may be represented by only a single living species |
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Term
| Approximately how many species have been catalogued to date? |
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Definition
| Approximately 1.5 million species have been catalog to date |
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Term
| Describe the two general approaches used to estimate the total number of species |
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Definition
1) using intensive surveys of species rich groups at small sites
2) attempting to identify all of the species present in a particular region |
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Term
| What is the estimated range of the total species of arthropods in existence? |
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Definition
| Estimates range between 10 million and 100 million species |
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Term
| Where is biodiversity highest? |
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Definition
| In most taxonomic groups, species richness is highest in the tropics and declines towards the polls |
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Term
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Definition
| Hotspots are regions that are much more species rich than others |
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Term
| What are the criteria for a conservation hotspot? |
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Definition
| Conservation hotspots are regions that contain at least 1500 endemic plants species and for which at least 70% of their traditional or primary vegetation has been lost |
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Term
| How do modern extinction rates compare to those of the past? |
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Definition
| Modern rates of extinction are 100 to 1000 times greater than the average, or background, rate recorded in the fossil record over the past 550 million years |
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Term
| What is the cause of the recent increase of extinctions? |
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Definition
| Recent extinctions are being caused by the demands of a rapidly growing human population |
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Term
| Where have most of the extinctions that occurred over the past thousand years taken place? |
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Definition
| Most extinctions occurred over the past thousand years took place on the islands as a result of overhunting or introduction of exotic species |
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Term
| What are endangered species? |
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Definition
| Species that are almost certain to go extinct without effective conservation programs |
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Term
| What has recently become the most primary threat to endangered species? |
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Definition
| Habitat distraction has replaced overhunting and species interaction as the primary threats such species |
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Term
| What is habitat fragmentation? |
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Definition
| Habitat fragmentation is the break up of large, contiguous areas of natural habitat into small, isolated pieces |
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Term
| Why is habitat fragmentation a threat to species? |
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Definition
- Habitat fragmentation can reduce habitats to a size that is too small to support some species.
- fragmentation may result in smaller populations which can cause inbreeding and random loss of alleles due to genetic drift |
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Term
| How do biologists predict future extinction rates? |
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Definition
| Biologists use direct counts and species area relationships to estimate current extinction rates and predict how they might change in the future |
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Term
| What direct counts have yielded the best information on current extinction rates? |
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Definition
| The best information on current extinction rates concert studies on birds |
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Term
| What does recent analysis suggest the current extinction rate for birds is? |
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Definition
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Term
| How high is the current rate of extinction for birds, as compared to the background rate? |
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Definition
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Term
| Why is the conservation of biodiversity urgent? |
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Definition
| Extinction is irreversible, unlike other environmental problems |
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Term
| What is the only solution to the biodiversity crisis? |
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Definition
| To prevent the loss of alleles, species and ecosystems |
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Term
| What is the underlying cause to almost every biodiversity crisis? |
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Definition
| Socioeconomic factors that encourage the short-term overexploitation the land and other resources and discourage long-term sustainability of resources |
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Term
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Definition
| Sustainability is the managed use of resources at a rate only as fast as the rate at which they are replaced |
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Term
| What does the stability of a community refer to? |
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Definition
1) the ability to withstand a disturbance without changing
2) the ability to recover to former levels of productivity or species richness after disturbance
3) the ability to maintain productivity and other aspects of ecosystem function as conditions change over time |
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Term
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Definition
| Resistance is a measure of how much a community is affected by disturbance |
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Term
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Definition
| Resilience is a measure of how quickly a community recovers following a disturbance |
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Term
| True or false: diversity leads to high resilience and moderate resistance |
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Definition
| False: diversity leads to high resistance and resilience |
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Term
| What is the gap analysis program? |
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Definition
| The gap analysis program identifies gaps between geographic areas that are particularly rich in biodiversity and areas that are actually managed for conservation |
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Term
| What do the recent gap analyses suggest about our current conservation efforts? |
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Definition
| They suggested it may not be enough to conserve many species |
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Term
| What percentage of the earth's surface is currently being managed for biodiversity conservation |
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Definition
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Term
| What is the purpose of the newly created wildlife corridors? |
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Definition
| To connect populations that would otherwise be isolated |
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