Ch 56 - Conservation Biology & Global Change

Question 1

Describe the three levels of diversity.

Answer 1

1. Genetic diversity: increased variation results in increased adaptive traits
2. Species diversity: the sum of species richness + species evenness, a.k.a. the variety of species
3. Community/ecosystem diversity: the “variety of the biosphere’s ecosystems.” The sum of “intricate webs” of species; the local extinction of one species can have a negative impact on other species in the ecosystem.

Question 2

Describe the threat of habitat destruction.

Answer 2

• Greatest threat to biodiversity
• Caused by urbanization, fragmentation, agriculture, etc.
• Cause of 80% of all extinct & declining species

Question 3

Describe the threat of overexploitation.

Answer 3

• The harvesting of populations at a rate that exceed sgrowth
• K-selected and limited range species most vulnerable

Question 4

Describe the threat of introduced species.

Answer 4

• These species are free from limitations of natural habitat (no native diseases, predators)
• Can drive native species to extinction
• Cause of 40% extinctions and billions of dollars in removal and control
• 5,000 - 50,000 non-native species in the US

Question 5

Describe the threat of nutrient enrichment.

Answer 5

• Nutrient cycles are disrputed via: manipulation of water/nutrients, agriculture, contamination of aquatic ecosystems.
• Agriculture & nitrogen cycling - nitrogen removed with crops are replaced via fertilizer, causing increased nitrogen oxides into atmosphere causing atmospheric warming, ozone depletion, acid precipitation.
• Contamination of aquatic systems - culture eutrophication can exceed critical load causing contaimination, algae blooms/dead zones.

Question 6

Describe the threat of synthetic chemicals.

Answer 6

• not found in nature
• don’t decompose or become toxic via chemical reactions
• can be eaten/absorbed by organisms.

Question 7

Describe the threat of oil spills.

Answer 7

• often rapid death from direct contact with oil; absorbed through skin or ingested
• destorys insulatory properties of fur & feathers.

Question 8

Describe the threat of toxic metals.

Answer 8

• usually present in small amounts, but human activity causes increase in concentration
• e.g. facotries, cars, waste management, mining, etc.
• Exceeds capacity of system to cycle them naturally.

Question 9

Describe the threat of acid precipitation.

Answer 9

• damages & kills
• alters soil & water nutrietns & chemistry
• affects food web dynamics
• affects vulnerable life stages

Question 10

Describe the threat of global change: atmospheric CO₂ increases.

Answer 10

• Occurs via fossil fuel burning, deforestation, other human activities (ex: cattle farming)
  
  • Reflects radiation back to Earth
  • H₂O vapor & other gases causes greenhouse effect
  • Amplified greenhosue effect causes global warming
• Causes…
  
  • expansion and rise of oceans
  • More wildfires
  • Change in distribution of biomes
  • Species declines
  • Spread of tropical diseases
  • Effects on rainfall pattersn & water availabiltiy
  • Effects on development, growth & reproduction

Question 11

Describe the thread of global change: ocean acidification.

Answer 11

• Occurs when bodies of water abosrb CO₂ from the air
• CO₂ + H₂O react to form carbonic acid
• Carbonic acid dissolves calcium carbonate skeletons of organisms like corals, molluscs, and prevents shell formation

Question 12

Describe the thread of global change: depletion of atmospheric O₃.

Answer 12

• Ozone layer abosrbs UV radiation
• Chlorine in chlorofluorocarbon (CFCs) convert ozone to oxygen
• Chlorine now in atmosphere will react with ozone for approx. 100 years
• Some consequences include:
  
  • increased cancer & cataracts
  • DNA damage and decreased growth in photosynthetic organisms

Question 13

Describe fragmentation & edge landscape structure.

Answer 13

• Edge: boundary between patches featuring unique phsical conditions which vary in width & permeability
  
  • More fragmentation = more edges.
• Some species thrive because use resourecs from both patches
• Interior species have increased sensitivitiy, especially in smaller fragments.

Question 14

Describe corridor landscape structures.

Answer 14

• Connect patches & populations
• Length & width determine movement rates
• Can be natural or man-made
• Allow migration & dispersal but can increase disease transmission

Question 15

Describe the SLOSS debate.

Answer 15

• “Single Large or Several Small”
• Diamond presented “single large” idea stating more species are persent in a larger block of area than in all of smaller blocks
• Simberloff presented “several small” stating that if a smaller patch has species not found in other patches, then several small could have mroe species than single large
  
  • a.k.a. not “all eggs in one basket.”

Question 16

Describe **establishing protected areas **and biodiversity hot spots.

Answer 16

• Biologists tend to focus on hot spots of biodiversity to propose protected areas
• A biodiversity hot spot is a small area with nuermous endemic species (not found anywhere else in the world) and a large number of endangered/threatened species.
• With increased landscape fragmentation, it becoems harder to set aside large enough reserves to sustain minimum viable population (MVP) of mayn species.

Question 17

Describe ways to reverse global change.

Answer 17

• Reduce pollution & use clean energy:
  
  • Create anti-pollution laws and pollution taxes, use alternative & renewable energy sources
• Conserve non-renewable resources:
  
  • e.g. topsoil, groundwater/freshwater, fossil fuels
• Preserve endangered species:
  
  • restore habitats, breeding programs maintaining genetic diversity
• Impose sustainable development:
  
  • Meet the needs of people today & in future while preserving biodiversity
• Get involved:
  
  • Be actove
  • Stay informed
  • Vote
  • Remember the butterfly effect…