3.8 - Threats to biodiversity

Question 1

after overexploitation a population may…

Answer 1

recover

Question 2

some species have a naturally low ……. in their population and yet remain ……

Answer 2

genetic diversity, viable

Question 3

what is the bottleneck effect?

Answer 3

when small populations lose the genetic variation needed to enable evolutionary responses to environmental changes

Question 4

in small/low genetically diverse populations what can result in poor reproductive rates?

Answer 4

inbreeding

Question 5

what has led to habitat fragmentation?

Answer 5

habitat clearing

Question 6

what does the degradation of the edges of habitat fragments lead to?

Answer 6

increased competition between species and a decrease in biodiversity

Question 7

Genetic diversity: (not required to memorise)

Answer 7

genetic variation of the number and frequency of alleles of a specific gene

Question 8

Species diversity: (not required to memorise)

Answer 8

two factors - the number of different species in an ecosystem and the proportion of each species in the ecosystem.

Question 9

Ecosystem diversity: (not required to memorise)

Answer 9

the number of distinct ecosystems in a defined area

Question 10

what type of fragments exhibit a lower species diversity?

Answer 10

• more isolated fragments

- smaller fragments

Question 11

what can link habitat fragments?

Answer 11

habitat corridors

Question 12

habitat corridors are to remedy what?

Answer 12

widespread habitat fragmentation

Question 13

habitat corridors increased access to what?

Answer 13

food and choice of mate

Question 14

local extinctions in isolated fragments can be combated with?

Answer 14

habitat corridors

Question 15

introduced/non-native species are species which have been…

Answer 15

moved intentionally or accidentally to new geographic locations

Question 16

introduced species which form wild populations are termed:

Answer 16

naturalised

Question 17

invasive species directly reduce ……… diversity

Answer 17

species

Question 18

invasive species may be successful because they are free from …….. , …… , ……… and …….. which ……. their population in their native habitat

Answer 18

predators, parasites, pathogens, competitors, limit

Question 19

what characteristic makes invasive species hard to combat?

Answer 19

they spread rapidly

Question 20

what do invasive species do to native species?

Answer 20

outcompete for resources , prey on, hybridise with,