Biology · Unity and diversity

A4.1 — Evolution and speciation

Biology · SL / HL · syllabus-mapped notes

1. A4.1.1

   Evolution as change in the heritable characteristics of a population

   Define evolution as change in the heritable characteristics of a population, and distinguish it from Lamarckism.

2. A4.1.2

   Evidence for evolution from base sequences in DNA or RNA and amino acid sequences in proteins

   Explain how DNA, RNA and protein sequence data give evidence of common ancestry.

3. A4.1.3

   Evidence for evolution from selective breeding of domesticated animals and crop plants

   Explain how selective breeding of domesticated species is evidence for evolution.

4. A4.1.4

   Evidence for evolution from homologous structures

   Explain how homologous structures are evidence for evolution, using the pentadactyl limb.

5. A4.1.5

   Convergent evolution as the origin of analogous structures

   Explain how convergent evolution produces analogous structures, with an example.

6. A4.1.6

   Speciation by splitting of pre-existing species

   Explain that new species arise only by the splitting of existing species.

7. A4.1.7

   Roles of reproductive isolation and differential selection in speciation

   Explain the roles of reproductive isolation and differential selection in speciation.

8. A4.1.8

   Differences and similarities between sympatric and allopatric speciation

   Give the differences and the similarities between sympatric and allopatric speciation.

9. A4.1.9

   Adaptive radiation as a source of biodiversity

   Explain how adaptive radiation increases biodiversity.

10. A4.1.10

    Barriers to hybridization and sterility of interspecific hybrids as mechanisms for of preventing the mixing of alleles between species

    Explain how barriers to hybridization and hybrid sterility keep species separate.

11. A4.1.11

    Abrupt speciation in plants by hybridization and polyploidy

    Explain how hybridization and polyploidy cause abrupt speciation in plants.