c.4- conservation and biodiversity

Question 1

define an indicator species

Answer 1

an organism used to assess a specific environmental condition

Question 1

why are certain species good indicators?

Answer 1

because they only occur when specific environmental conditions are present

Question 2

how can we calculate the value of a biotic index?

Answer 2

by using relative numbers/frequencies of indicator species

Question 3

state the equation for biotic index

Answer 3

check

Question 4

A high biotic index indicates

Answer 4

the presence of many pollution-sensitive organisms, denoting an unpolluted environment

Question 5

A low biotic index indicates

Answer 5

a relative abundance of pollution-tolerant organisms, denoting a polluted environment

Question 6

define in situ conservation

Answer 6

measures involving endangered species remaining in the habitat to which they are adapted

Question 7

in situ conservation may require

Answer 7

active management of nature reserves or national parks, eg:
- controlled grazing
- removal of shrubs and trees

Question 8

define ex situ conservation

Answer 8

measures involving removal of organisms from their natural habitat.

Question 9

state a case study of the captive breeding and reintroduction of an endangered animal species

Answer 9

Peregrine falcon
- became endangered because of the widespread use of DDT
- conservation workers collected eggs from nests and replaced them with porcelain replicas , then incubated them
- this ensured a greater frequency of hatching

Question 10

state the two components of biodiversity

Answer 10

richness and evenness

Question 11

define richness

Answer 11

the number of different species present

Question 12

define evenness

Answer 12

how close in numbers each species is

Question 13

give the formula for Simpson’s reciprocal index of diversity

Answer 13

check

Question 14

what does the Simpson’s reciprocal index of diversity do?

Answer 14

it quantifies biodiversity by taking richness and evenness into account

the higher the value of D, the higher the biodiversity.

Question 15

—— ——- can affect species diversity

Answer 15

biogeographic factors

Question 16

analyse the impact of island size on diversity

Answer 16

Biodiversity is proportionate to island size

Larger islands:

• support a greater range of habitats (and hence more available niches for species to occupy)
• sustain higher population numbers for each species (increases species evenness)
• greater productivity at each trophic level, leading to longer and more stable food chains

Question 17

analyse the impact of edge effects on diversity

Answer 17

Edge effects occur at ecotones (where two habitats meet and there is a change near the boundary). More species exist at ecotones as species from different habitats converge leading to increased predation and competition.

However certain species may not be able to thrive under these conditions and instead must occupy more central regions.

These effects depend on the particular abiotic conditions.