modules 3 and 4 Flashcards
From an energy standpoint, why is it important to eat low on the food chain?
Because about 90% of energy is lost at each level so it is less energy costly to eat lower on the food chain.
Explain the difference between density-dependent and density-independent forms of environmental resistance. give an example
environmental resistance is the ways in which the environment limits growth
density-dependent factors: growth is limited by density of population
- supply of nuts is based on squirrel population and vice versa
density-independent factors: growth is limited by factors that have nothing to w/ size of population
- polar vortex leads to cold temps and inability for the squirrels to survive the cold which will decrease the squirrel population
carrying capacity
number of organisms that a region can support without environmental degradation
mutualism
both organisms benefit
example: bees and flowers (pollination)
commensalism
1 organism benefits, other 1 is neutral
example: fish hiding in coral
competition
1 benefits, 1 suffers/gets consumed
example: cheetah hunting a zebra
Describe an example of how the removal of a predator species can have effects throughout the entire food chain.
With fewer total predators, the regulation of the animals directly below in the food chain will decrease. They will then thrive and as their population increase they will eat more of the lower levels. This can lead to a depletion of the lower levels; therefore, the available food for the species that initially thrived will be gone and eventually this can lead to the end of an ecosystem.
What are 2 variables that distinguish biomes from each other besides the typical vegetation cover?
precipitation
temperature
soil type
ecosystem services
provisioning
regulating
cultural
supporting
provisioning
provides services
food, raw materials, water, medicine
regulating
regulates:
air quality
climate
water
waste
erosion
disease
extreme events
pollution
cultural
mental/physical health
recreation
aesthetics
spiritual/religious values
supporting
nutrient cycling
soil formation
photosynthesis
Explain how one could try to assess the value of ecosystem services provided by a particular species. Why would it be helpful to assess this?
bats:
1 bat species on a cotton farm consumes insects so because of this they’re valued. they save about 15% of the cotton from being eaten by insects so they’re valued at 15% of the farm’s total sales. Without some measure of ecosystem services, the services may be undervalued, and it may be difficult to assess needed funding for sustainable management of these resources/to track the condition of nature or its economic role and value.
Describe two reasons why there tends to be higher species abundance nearer the equator.
the climate is warmer and more consistent
no ice sheets
Explain why we should care about biodiversity hot spots.
they have endemic species and have less than a third of original vegetation
endemic species
any species whose range is restricted to a limited geographical area
What different metrics do the Living Planet Index and IUCN Red List track?
number of population of different species
threatened species and level of threat
There are two components to the Multidimensional Biodiversity Index. explain the difference between the two and which one focuses on instrumental values.
2 components: biodiversity for nature and biodiversity for people
Biodiversity for nature measures diversity, abundance, and function. Biodiversity for people measures regulation, materials and assistance, and non-materials; this focuses on instrumental value and measuring how nature is useful for humans.
What are the largest two global land uses?
pasture
cropland
Name some ecosystem services of forests and wetlands, and classify them.
forests: stabilize soil (r), prevent erosion (r), purify water (r,p), release oxygen (r), moderate climate (r), play role in nutrient cycling (s), wood (p)
wetlands: remove pollutants (r), attract people for recreation (c), store carbon (r), absorb and store water (r)
Consider a palm oil plantation. Which of the forest ecosystem services are still provided by it, and which were lost when the natural forest was converted to a monoculture?
keep: carbon storage and runoff reduction (regulation and provisioning)
lose: biodiversity (affects regulation and nutrient cycling in soil-supporting)
What are the particular factors that lead to the different patterns of deforestation? (fishbone, radial, dendritic, rectangular)
roads, small-scale farming, large farming (slash and burn), paths to transport goods
How do current rates of change in forest cover differ between temperate and tropical forests?
temperate forests are recovering and have a net gain of forest
tropical forests are still in a net loss