3.3 Threats to Biodiversity

Question 1

How can we estimate the number of species? (3 methods)

Answer 1

1. Host-specific species
2. Ratio of temperate and tropical species
3. Taxonomic classification system

Question 2

Host-specific species method - explain

Answer 2

Intensively count the number of species in an area and then extrapolate to a wider area

Question 3

Ratio of temperate and tropical species

Answer 3

• Using the ratio that that there are more than 2-3 times more animals in the tropics an assumption has been made that this ratio can be applied across all other groups of species… around 3 million

Question 4

Taxonomic classification system

Answer 4

animals are designated a kingdom based on their phisical characteristics

Question 5

Problems with counting species (HINT: 5)

Answer 5

• variation within a species may cause for them to be counted twice
• very small species such as bacteria are difficult to isolate
• some species are difficult to access (deep sea)
• Species become exctinct before we know of their existence
• lack of finances

Question 6

How can human presence affect habitats?

Answer 6

• Conversion of habitats to urban land
• Removal for agricultural purposes
• Fragmentation through transport routes such as roads and railways
• Degradation through over-exploitation of natural resources such as timber
• Degradation through pollution

Question 7

How do humans influence biodviersity?

Answer 7

• Population growth
  • increase in demand of natural resources
    • over-exploitation of resources, habitat degradation, habitat fragmentation, pollution
• Overfishing (newfoundland case study)
• Habitat fragmentation
  
  • eg. Paracas
• Habitat degradation and loss
  
  • agricultural revolution 1950s with mechanization farming intensified → large scale farming
• invasive species
• Climate change
  • causes change in precipitation patterns

Question 8

How does the IUCN red list classify its species (categories)

Answer 8

Least Concern
Near threatened
Vulnerable
Endangered
Critically endangered
Extinct in the wild
Extinct

Question 9

What is the criteria that the IUCN red list uses to classify its species

Answer 9

• Population size
• Geographical range
• Number of locations
• Extent of habitat fragmentation
• Quality of habitat
• Trophic level

Question 10

What are biological hotspots?

Answer 10

must have:

• a high level of endemic species
• endemic species under threat

Question 11

What are the quantative methods that myers introduced?

Answer 11

• 1,500 vascular endemic plants
  
  • high percent of plant life found nowhere else in the planet
• 30% or less of its original vegetation- aka very under threat

Question 12

Why are biological hotspots useful

Answer 12

• allows conservation efforts to be focused in areas where it can protect the highest numbers of species
• They occupy only 2.3% of Earth’s land area but contain approximately 50% of the earth’s endemic plant species and 42% of all terrestrial vertebrates
• 2.3 % earths land
• 50% earths endemic plants
• 42% terrestrial vertebrates

Question 13

How many biodiversity hotspots are there?

Answer 13

there are 35 global biodiversity hospots, most in the tropical biomes 🌴

Question 14

How can rainforest be vertically divided?

Answer 14

Emergent layer - 100% ☀️

Canopy layer - 95% ☀️

Understory layer - 5% ☀️

Forest Floor - - 2%☀️

Question 15

Make sure you can apply different Environmental Value Systems (EVS) to the different choices made on whether or not to conserve natural resources such as habitats and species

Answer 15

Mira tu tablita