In Classification: Hippo Case Study, students investigate how and why scientists classify animals. Using hippos as a focal point they will look at observable characteristics and phylogenetic trees to compare the different methods of classifying animals as well as how modern technologies have altered taxonomical decisions. They will also explore the real world uses of classification, such as how ZSL uses taxonomy to help make conservation decisions.

Specimens used in this session have been donated to Whipsnade Zoo by HM Revenue and Customs.

Age: Post 16 Duration: 60mins Capacity: 35 students Indoor workshop
Common hippo with calf a at Whipsnade Zoo

Intended learning outcomes:

Students will be able to:

  • List and compare the strengths and weaknesses of the different approaches that have been used to classify species
  • Work in groups to determine the lineage of a range of species using a classification toolkit
  • List ways in which taxonomical decisions have changed with the advent of modern technologies
  • Describe how species evolve into the species we see today
  • Describe how the zoo uses classification and phylogenetic trees to help in making conservation decisions.

Additional Resources:


AQA Biology AS & A Level
3.4 Genetic information, variation and relationships between organisms 3.4.1 DNA, genes and chromosomes
  • A gene is a base sequence of DNA that codes for:
    • the amino acid sequence of a polypeptide
3.4.2 DNA and protein synthesis
  • Students should be able to:
    • relate the base sequence of nucleic acids to the amino acid sequence of polypeptides
3.4.3 Genetic diversity can arise as a result of mutation or during meiosis
  • Gene mutations involve a change in the base sequence of chromosomes. They can arise spontaneously
3.4.5 Species and taxonomy
  • A phylogenetic classification system attempts to arrange species into groups based on their evolutionary origins and relationships. It uses a hierarchy in which smaller groups are placed within larger groups, with no overlap between groups. Each group is called a taxon (plural taxa).
  • One hierarchy comprises the taxa: domain, kingdom, phylum, class, order, family, genus and species. Each species is universally identified by a binomial cons
  • Students should be able to appreciate that advances in immunology and genome sequencing help to clarify evolutionary relationships between organisms.
3.4.7 Investigating diversity
  • Genetic diversity within, or between species, can be made by comparing:
    • the frequency of measurable or observable characteristics • the base sequence of DNA
    • the base sequence of mRNA
    • the amino acid sequence of the proteins encoded by DNA and mRNA.
  • Students should be able to:
    • interpret data relating to similarities and differences in the base sequences of DNA and in the amino acid sequences of proteins to suggest relationships between different organisms within a species and between species
    • appreciate that gene technology has caused a change in the methods of investigating genetic diversity; inferring DNA differences from measurable or observable characteristics has been replaced by direct investigation of DNA sequences.
3.7 Genetics, populations, evolution and ecosystems 3.7.1 Inheritance
  • The genotype is the genetic constitution of an organism. The phenotype is the expression of this genetic constitution and its interaction with the environment.
Pearson Edexcel A Level Biology A (Salters-Nuffield)
Topic 2: Genes and Health
  • 2.8 Know that a gene is a sequence of bases on a DNA molecule that codes for a sequence of amino acids in a polypeptide chain.
  • 2.13
    • i) Know the meaning of the terms: gene, allele, genotype, phenotype
Topic 4: Biodiversity and Natural Resources
  • 4.1 Know that over time the variety of life has become extensive but is now being threatened by human activity.
  • 4.4 Understand how natural selection can lead to adaptation and evolution.
  • 4.6
    • i) Understand that classification is a means of organising the variety of life based on relationships between organisms using differences and similarities in phenotypes and in genotypes, and is built around the species concept.
    • ii) Understand the process and importance of critical evaluation of new data by the scientific community, which leads to new taxonomic groupings, including the three domains of life based on molecular phylogeny, which are Bacteria, Archaea, Eukaryota
  • 4.16
    • Be able to evaluate the methods used by zoos and seed banks in the conservation of endangered species and their genetic diversity, including scientific research, captive breeding programmes, reintroduction programmes and education.
Pearson Edexcel A Level Biology B
Topic 1: Biological Molecules 1.4 DNA and protein synthesis
  • iii) Know that a gene is a sequence of bases on a DNA molecule coding for a sequence of amino acids in a polypeptide chain.
Topic 3: Classification and Biodiversity 3.1 Classification
  • i) Know that the classification system consists of a hierarchy of domain, kingdom, phylum, class, order, family, genus and species.
  • iii) Understand why it is often difficult to assign organisms to any one species or to identify new species.
  • vii) Understand the evidence for the three-domain model of classification as an alternative to the five-kingdom model and the role of the scientific community in validating this evidence.
Topic 10: Ecosystems 10.4 Human effects on ecosystems
  • i) Understand data relating to human influences on ecosystems, including climate change and depletion of biological resources, including overfishing.
OCR A Level Biology A
Module 4: Biodiversity, evolution and disease 4.2 Biodiversity 4.2.2 Classification and evolution
  • (a) the biological classification of species
  • (b) the binomial system of naming species and the advantage of such a system
  • (c)
    • (i) the features used to classify organisms into the five kingdoms: Prokaryotae, Protoctista, Fungi, Plantae, Animalia
    • (ii) the evidence that has led to new classification systems, such as the three domains of life, which clarifies relationships
  • (d) the relationship between classification and phylogeny
Module 6: Genetics, evolution and ecosystems 6.1 Genetics and evolution 6.1.3 Manipulating genomes
  • (b)
    • (i) how gene sequencing has allowed for genome-wide comparisons between individuals and between species


OCR A Level Biology B
Module 3: Cell division, development and disease control 3.1 Cell division and development 3.1.3 The development of species: evolution and classification
  • (a) the concepts of biological classification and species
  • (b) the types of evidence used in biological classification and consideration of how theories change as new evidence is found
  • (d) the interpretation of phylogenetic trees and genetic data to show relatedness and classification in plants and animals


Cambridge International AS & A Level Biology
18 Biodiversity, classification and conservation 18.2 Classification Organisms studied locally may be used to show how hierarchical classification systems are organised.
  • a) describe the classification of species into the taxonomic hierarchy of domain, kingdom, phylum, class, order, family, genus and species
  • b) outline the characteristic features of the three domains Archaea, Bacteria and Eukarya
  • c) outline the characteristic features of the kingdoms Protoctista, Fungi, Plantae and Animalia