In this topic of IBDP Biology, we will learn about classification.

• Vast diversity of living organisms – up to 100 million species.
• Allows us to identify the similarities and differences between organisms.
• Allows us to identify the evolutionary history of an organism.
• When it comes to IBDP Biology, it gives every organism a universal name, makes studying easier.
• Devised solely for human convenience – organisms actually form a continuum.

• A group of organisms belong to a species if:
  • They can reproduce together to produce fertile offspring.
    • Closely related species may be able to reproduce to create offspring.
      • These offspring are often infertile, eg mules from horses and donkeys.
      • They cannot produce fertile gametes.
  • When it comes to IBDP Biology, they share observable similarities that members of other species do not possess.
    • Biochemistry
    • DNA
    • Physical similarities
    • Patterns of development - embryology
    • Behavioural
    • Same ecological niche
• Closely related species may be behaviourally incompatible, so they cannot reproduce.
• However, this is difficult to define.
  • Eg grizzly and polar bears can reproduce.
  • They have different:
    • Niche – different territories
    • Behaviour – grizzly bears are more aggressive
  • It is not known whether their offspring are fertile.
  • Even if they are, they would still be defied as separate species, unless their hybrids were found to be freely reproducing.

• Each species is given a unique name
• When it comes to IBDP Biology, It involves the binomial system.
• Consists of genus and species in Latin:
  • Eg Homo sapiens

You get it now. Now you can proceed to Part 2.

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