Sabtu, 02 Juli 2016

#154 Summary Biodiversity and conservation

1 All living organisms may be classified into one of the five kingdoms: prokaryotes, protoctists, fungi, plants and animals.

2 Biodiversity includes the range of habitats (environments) and species in an area, and the genetic diversity within a species.







3 There are moral and ethical reasons for maintaining biodiversity, and also more practical ones. For example, we may be able to use plants to provide medicines, and animals to provide alleles to use in animal breeding.

4 Species may become in danger of extinction through habitat loss, change to their environment (perhaps as a result of pollution) and overexploitation by humans.

5 Conservation of an endangered animal species may involve captive breeding programmes, in which viable populations are built up in zoos and wildlife parks. These programmes try to ensure that the gene pool is maintained and inbreeding is avoided. At the same time, attempts are made to provide a suitable habitat in the wild, so that captive-bred animals can eventually be re-released into the wild. Local people are involved, because this increases acceptance of the project and the chances of its success.

6 Botanic gardens and seed banks help to conserve threatened plant species by breeding them for reintroduction into an appropriate habitat. Seed banks provide suitable conditions to keep different types of seeds alive for as long as possible. Samples of the seeds are grown into adult plants every now and then, so that fresh seed can be collected.

7 Many countries have protected areas called national parks, which often cover large areas. These are set up to conserve rare and endangered species and to maintain their habitats. Often legislation is passed to ensure their protection. In such areas, agriculture is controlled and building, mining and other industries strictly regulated. Access is often limited but not forbidden, as one aim of most such parks is to educate people about the importance of conservation. 8 Other, smaller, conservation areas may be created to protect particular species and habitats.

1. End-of-chapter questions

 Which organism is a fungus?


2   Which   of the  statements    about   Protoctista    are correct?
   1   a eukaryote   that  is not  a fungus,   plant   or animal   is a protoctist
   2    an organism   with  cellulose  cell walls  and  chloroplasts    may  be a protoctist
   3    an organism   existing  as a group   of similar  cells may  be a protoctist
   4    a single-celled   heterotrophic     eukaryote   is a protoctist

 A   1,2,3 and  4          B   1, 2 and 4 only  C   2 and 3 only           D 3 and 4 only


3   A gene  bank  is a store  of the  genetic  variation   of a species.  Which   of the  following   are gene  banks?
1   captive  animals   in a zoo                                                                     
2    plants  in a botanic   garden
3    seeds in a seed bank
4    plant  cells growing   in tissue  culture
5   frozen  sperm,   eggs or embryos

A  1, 2, 3, 4 and 5   B   1, 2 and 3 only      C  2, 3 and  4 only   D   3, 4 and  5 only


4   Copy  and  complete   the  table  to show  the  features   present   in the  five different   classificatory   Kingdoms    of living organisms.   Use a tick  (V")   to show  the  presence   of a feature  and  a cross  (x)  to show  its absence.
Add caption
5   Distinguish   between   orthodox    and  recalcitrant     seeds.
6   a    Explain  what  is meant   by biodiversity. [2]
     b    Over  half  of the  living  species  of plants   and  animals   live in  tropical   rainforests.    Suggest  why  this  is so. [4]
    c    Some  rainforest   species,  for  example   the  squirrel   monkey   in Costa  Rica,  are endangered.    Suggest  four  ways to  conserve  an animal   species  such  as the  squirrel   monkey.[4]
   d    List four  practical   reasons  why  humans   should   try  to maintain    biodiversity. [4]
[Total:   14]

7 a In  many   cases,  the  reason   for  an  organism    becoming    endangered    is the  loss of its habitat   as a result  of human activity.   List  four ways  in which   human    activity   causes  habitat   loss. [4]
       b In  1973,  the  population  of African   elephants  in  Kenya was about 167000 animals,  but  by 1989 the population had  dropped to about 16000  animals. In  2010 the  population had  risen  to  about  36000  animals. Suggest explanations for  these  changes. [6]
c Explain: 
             i  how  captive   breeding   of animals,   such  as the  scimitar-horned    oryx,  can  help  conserve   an endangered    species; [3]
            ii  how genetic diversity can be maintained  during a captive breeding programme.     [3] 
[Total:  16]


8  The  American  crocodile,  Crocodylus acutus, was classified  as an endangered  species  by the  USA  in  1975.  It is found in  estuarine  regions  of southern  Florida.

The  salinity   of the  water  was  thought    to  playa   part  in  the  distribution     of the  American    crocodile.   The  figure  shows the  number    of American    crocodile   nest  sites  in  areas  with  water  of varying   salinity   in southern    Florida.

a    Describe   the  results  shown   in  the  figure.               [3]

b    Much   conservation   work  has  been  done  in  the  Everglades   National    Park  in  Florida,   which   is a large wetland area.  As a result,   the  number    of nest  sites  increased   from  eight  in  1975  to 31  in 2000.   This  led  to a rise in the number    of crocodiles.  

  i  Calculate    the  percentage    increase   in  nest  sites  between    1975  and  2000.   Show  your  working.[2]
  ii    Suggest   two  reasons  why  the  population     of crocodiles   in  the  Everglades   National    Park  has  increased.[2]
[Total:  7]

[Cambridge International  AS and A Level Biology 9700/42,   Question 1, Mayljune2010,]                                                                                                          


2. End-of-chapter answers
 1 D
 2 A
 3 A
 4

5 orthodox seeds: can be dehydrated and frozen for long-term storage;

   recalcitrant seeds: cannot be dehydrated and frozen;


Exam-style questions


6 a biodiversity:
      range/variety, of, species/communities/ecosystems;
      the genetic variation within a species;
      the genetic variation between species; [max. 2]

  b high rate of photosynthesis/rapid growth of plants; allows large number of plant species;
     available throughout the year;
      provides niches for large number of animal species; [4]

 c maintain as a captive population in a zoo/captive breeding;
    set up conservation area/protect habitat from clearance;
    ban, hunting/capture;
   educate public/introduce ecotourism; [4]

d as resource for, food/materials;
    as source of alleles for breeding to improve agricultural species;
    as potential medicines; for ecotourism/leisure;
    to maintain, food webs/nutrient cycles; [max. 4]
 [Total: 14]

7 a clearing land for agriculture;
      clearing land for housing;
      clearing land for industrial building;
      clearing land for, road building/railways/pipelines/
     other infrastructure;
     mining;
     logging;
     pollution/global warming; [max. 4]

 b fall from 167 000 to 16 000 due to a combination of factors including:
    ivory hunting;
    game hunting;
    hunting for meat;

    killing after damage to village crops;
   habitat loss;
    rise after 1989 due to ban on ivory trading;
    rise only to 36 000 because other factors still apply: habitat loss;
   poaching;
   killing after damage to village crops; [max. 6]

c i bred in several places so not all at risk from same disease;
     increased numbers of animals;
     allows return of animals to wild; [3]

  ii close relatives are not interbred; e.g. siblings/father with daughter;
    in-vitro fertilisation used to breed from distantanimals;
    refer to embryo donation and use of surrogates; [max. 3]
 [Total: 16]
8 a more nests in less saline areas;
     22 nests at 0–5 parts per thousand compared with 1 at 31–35 parts per thousand;
     anomalous result for 16–20 parts per thousand; [3]









       ii more fresh water/lower salinity;
          sites protected;
          ecotourism encouraged;
          ban on hunting;
          less pollution; [max. 2]
 [Total: 7]