18 Classification, biodiversity and conservation
Classification systems attempt to order all the organisms that exist on Earth according to their
... [Show More] characteristics
and evolutionary relationships with one another. There are opportunities in this topic for candidates to observe
different species in their locality and assess species distribution and abundance. Fieldwork is an important part
of a biological education because it provides opportunities to appreciate and analyse biodiversity, and to study
the interactions between organisms and their environment. The biodiversity of the Earth is threatened by human
activities and climate change. Conserving biodiversity is a difficult task; individuals, local groups, national and
international organisations can all make significant contributions. Candidates should appreciate the threats to
biodiversity and consider some of the steps taken in conservation, both locally and globally.
18.1 Classification Learning outcomes
Candidates should be able to:
1 discuss the meaning of the term species, limited to the
biological species concept, morphological species concept and
ecological species concept
2 describe the classification of organisms into three domains:
Archaea, Bacteria and Eukarya
3 state that Archaea and Bacteria are prokaryotes and that
there are differences between them, limited to differences in
membrane lipids, ribosomal RNA and composition of cell walls
4 describe the classification of organisms in the Eukarya domain
into the taxonomic hierarchy of kingdom, phylum, class, order,
family, genus and species
5 outline the characteristic features of the kingdoms Protoctista,
Fungi, Plantae and Animalia
6 outline how viruses are classified, limited to the type of nucleic
acid (RNA or DNA) and whether this is single stranded or double
stranded
18.2 Biodiversity Learning outcomes
Candidates should be able to:
1 define the terms ecosystem and niche
2 explain that biodiversity can be assessed at different levels,
including:
• the number and range of different ecosystems and habitats
• the number of species and their relative abundance
• the genetic variation within each species
3 explain the importance of random sampling in determining the
biodiversity of an area
4 describe and use suitable methods to assess the distribution and
abundance of organisms in an area, limited to frame quadrats,
line transects, belt transects and mark-release-recapture using
the Lincoln index (the formula for the Lincoln index will be
provided, as shown in the Mathematical requirements)
continued
18.2 Biodiversity continued Learning outcomes
Candidates should be able to:
5 use Spearman’s rank correlation and Pearson’s linear correlation
to analyse the relationships between two variables, including
how biotic and abiotic factors affect the distribution and
abundance of species (the formulae for these correlations will
be provided, as shown in the Mathematical requirements)
6 use Simpson’s index of diversity (D) to calculate the biodiversity
of an area, and state the significance of different values of D
(the formula for Simpson’s index of diversity will be provided, as
shown in the Mathematical requirements)
18.3 Conservation Learning outcomes
Candidates should be able to:
1 explain why populations and species can become extinct as a
result of:
• climate change
• competition
• hunting by humans
• degradation and loss of habitats
2 outline reasons for the need to maintain biodiversity
3 outline the roles of zoos, botanic gardens, conserved areas
(including national parks and marine parks), ‘frozen zoos’ and
seed banks, in the conservation of endangered species
4 describe methods of assisted reproduction used in the
conservation of endangered mammals, limited to IVF, embryo
transfer and surrogacy
5 explain reasons for controlling invasive alien species
6 outline the role in conservation of the International Union for
the Conservation of Nature (IUCN) and the Convention on
International Trade in Endangered Species of Wild Fauna and
Flora (CITES) [Show Less]