3.3 Threats to biodiversity

Question 1

state the number of speicies known to sciense (the number of spieces that have been found and named)a

Answer 1

approximatly 1.8 millio speices named and discribed.

Question 1

one esttimate for the total number of alive species on earth today is about 7 million. Explain why this answer is greater than the 1.8 million speices known to sciense?

Answer 1

• majority of speices are yet to be discovered + discribed.

-some groups such as terrestrial birds and mammals are better known.

-estimates depend on mathicataical modles.

-many habitats and groups of spesies are under-recorded as they are hard to reach or there is insuffienct funding.

Question 2

evaluate the current estimates of total species numbers on earth today?

Answer 2

-the estimate is reliable because it gives an indication of possible scale.

-the number of spesis alive on earth is not consistant over geological time periods.

-the number is unreliable as some smaller species insects, bacteria and other microbes have been overlooked.

some spesiese may have been counteded more than once (misslabled or or not compared to already idenditifed speices)

some speicees are difficult to access

Question 3

discuss how current extension rates compare to other gological periods?

Answer 3

the background rate of extinction from fossile records is between 10 to 100 species per year. Current extenstion rates has been estaimated to be about 3 species an. hour.

Question 4

what are all the ways humans are causes species loss?

Answer 4

habitat fragmentation and destruction

introduction of invasive species

pollution

agrtecultural pracsise

overharvesting (e.g fishing)

hunting/poaching

Question 5

can you expand on habitat fragmentations and disturction as a human factor cuasing spesicies loss?

Answer 5

habitats have been destroyed or devided for agreculture, mining or planting crops. Isolate habitats become isolated and hence vunrable.

Question 6

can you expand on introdcution of invasisve speices as a human factor cuasing spesicies loss?

Answer 6

upset the balance of an ecosystme, may outcompete native species.

Question 7

can you expand on agrecural practises as a human factor cuasing spesicies loss?

Answer 7

reduce biodiveristy with mono-culture, genertic enginnering, and the use of pestisides,

Question 8

can you expand on pollusion as a human factor cuasing spesicies loss?

Answer 8

introduces chemicals, litter, nets, plastic bags, oil spills which damage habitats and kills plants and animals, leading to a loss in population numbers.

Question 9

can you expand on overharvesting (e.g fishing) as a human factor cuasing spesicies loss?

Answer 9

human popualtion growth and improved fishing tequniques eans more sepieces are harvested from the ocean. Increasing by-catch reduces diversity.

Question 10

can you expand on hunting poaching as a human factor cuasing spesicies loss?

Answer 10

growing rural poverty and imporved methods of hunting means more and more people living at subsisencse levle over-exploite the envirment.

Question 11

what proportion of the earth is covered in tropical rainforests?

Answer 11

6%

Question 12

what persenatge of earths specises on earth live in the rain forest?

Answer 12

over 50%

Question 13

with reference to biodiverity hotspots, discribe the leves of speices and habitat diversity in tropical rainforest?

Answer 13

over alltropical rainforest have high species diverity and habitat diversity. BUT hotsports such as Malaysian peninsula have even more than others.

Question 14

what are the main three ecological services that rain forest provides?

Answer 14

oxegen production- high levels of heat, water and light year round eans photosynthesis is rapid and not limited.

nutient cyclining and soil formation- fast rate of respiration and decompisition increases nutrient cycling rates but most nutrients are held in plants not soil.

sequestration of carbon dioxide- rapid photosynthesis and all year round growth means the trees and other vegetation lock up carbon.

Question 15

what are the incomes of goods that the rainforest provides?

Answer 15

carbon sink
recreation
food
timber
medicine
intrinsic value
cultural value
filtering of water
spiritual value
soil stability
oxegen production

Question 16

outline how the amount of rainforest of earth has changed?

Answer 16

rainforesrt cover up to 14% of earth land surface in 1950 while today it is estamated at 8%

Question 17

give reasons for why there are so less rainforest now?

Answer 17

increased ranching and commerical logging.

increasing population pressure and loss of forests and clearnace means the forest does not fully regrow before it is cleared again leading to gradual degrigation of nutrients and biodvseity.

Question 18

in tropical bioms (as with many) there is a conflict between explotation, sustanible development and conservation. Outline this conflict?

Answer 18

MEDCs have the luxury to be able to preserve their remaining ecosystms as they do not s they do not rely on these areas to provide income.

Most tropica bioms are found in LEDCs where the land prvoides income for local communities.

Modern logging tequnices and more importanse placed on ecotourism can provide income without destoying natural income.

Question 19

why is the conflict of exploitation, sustanible development and conservation more complicated in LEDCS?

Answer 19

LECDs do not always have access to the latest technology.

In LEDCS, more of the population is reliant on subsistence farming are population increases more rapidly here.

Lack of infrastructure, political support and education may limit the option of eco-tourism.

Question 20

what are the advantages of human impacts on on biodivserity in tropical rainforests?

Answer 20

-direct service (wood medicine food)

-recreational value

-provides grazing land

-scientific research

Question 21

what are the disadvantages of human impacts on on biodivserity in tropical rainforests?

Answer 21

indirect services lost (CO2 production and sequestering, water filtration, temperature stability and soil stability)

biodiversity loss

loss of unidentified specises

Question 22

what are the factors that affect how prone a species it to extinction?

Answer 22

geographical range
genetic diversity
population diversity
body size
reproductive potential
migration
dispersers
specialised nich requeimrnet
usefullness to humans
island organisms

Question 23

can you expand on geographical range as a factor affecting how prone a species is to extinction?

Answer 23

the narrower the geographical range the more vulnerable. If the habitat is destroyed the speices will be too.

Question 24

can you expand on genetic diversity as a factor affecting how prone a species is to extinction?

Answer 24

small populations have lower genetic diversity which makes them more vulnerable to change

Question 25

can you expand on population diversity as a factor affecting how prone a species is to extinction?

Answer 25

the greater the population diversity the greater the chance of individuals reproducing successfully.

Question 26

can you expand on body size as a factor affecting how prone a species is to extinction?

Answer 26

larger animals tend to have larger ranges, low population densities and need a lot of food. They compete with humans for food, may be seen as dangerous and hunted for sport.

Question 27

can you expand on reporudctve potential as a factor affecting how prone a species is to extinction?

Answer 27

reproducing slowly and infrequently. means populations take a long time to recover. This increases venerability.

Question 28

can you expand on migration as a factor affecting how prone a species is to extinction?

Answer 28

organisms that migrate have the stress of migration routes and they need suitable habitats at both ends. One destination may not have food. barriers can prevent migration.

Question 29

can you expand on disperses as a factor affecting how prone a species is to extinction?

Answer 29

spesices that can not move to new locations (plants) are more vunrable.

Question 30

can you expand on specialised niche requirements affecting how prone a species is to extinction?

Answer 30

if a species has a specialised diet or habitat requirements, if it is put under threat so are they.

Question 31

can you expand on usfullness to humans as a factor affecting how prone a species is to extinction?

Answer 31

if they are hunted for sport or food their numbers can be quickly reduced especially if they live in larger groups.

Question 32

can you expand on island organisms as a factor affecting how prone a species is to extinction?

Answer 32

vulnerable as their populations tend to be small and genetic diversity tend to be low. Islands are more vulnerable to invasive species.

Question 33

what does the acronym IUCN stand for?

Answer 33

international union for the conservation of nature

Question 34

what in the IUCN red list?

Answer 34

red list of threatened species.

Red list deytermines the conservation status of a spies based of on population siz,e degree of spezilisation, distrobution, re[oductive potentional and behaviour, gepgraphical range tropic leves and probability of extinction.

Question 35

what are the categories the IUCN has, put them in order of most at risk of extntiction at the top?

Answer 35

extinct
extinct in the wild
critically endangered
endangered
venerable
near threatened
least consern
data defficent
not evaluated

Question 36

how do the IUCN describe their mission?

Answer 36

to influence, encurragfe and assist socities through put the world to conserve the integrety and diversity of nature and to ensure that any use of natural resorces is equitable and ecologically sustanible.

Question 37

why is cooperation needed to make the red list for the IUCN?

Answer 37

the genetic diversity represented by these species an irreplaceable resorce which needs to be conswerved through increased awareness.

the spies represent key building blocks of ecosystms and information on conservation stataus is needed for informed desions making from local and global scales.