Biology • Year 11 • Module 3 • Lesson 12
Comparative Embryology & Evidence for Evolution
Lock in the core vocabulary, what comparative embryology shows, the lines of evidence for evolution, and how antibiotic resistance arises before moving to application tasks.
1. Complete the paragraph
Fill each blank with the correct term from the word bank. Use each term once only. 8 marks
_______________ compares the early embryonic development of different species. The early embryos of fish, reptiles, birds and mammals all show gill-like structures called _______________ and a _______________, even though these develop differently in the adult. These shared features are inherited from a _______________, and the more similar two species' early development, the more closely related they tend to be. Evolution is supported by several _______________ lines of evidence that all point to the same conclusion. A modern example we can observe is _______________: within a bacterial population there is genetic _______________, and when an antibiotic is used, the resistant individuals survive and reproduce, which is _______________ in action.
2. Term–definition match
Write the matching term from this list in the right-hand column: comparative embryology • pharyngeal arches • common ancestor • lines of evidence • antibiotic resistance • natural selection • biogeography • comparative anatomy. 8 marks
| # | Definition | Matching term |
|---|---|---|
| 2.1 | Comparing the early embryonic development of different species as evidence of relatedness. | |
| 2.2 | Gill-like structures present in all early vertebrate embryos. | |
| 2.3 | An ancestral species from which two or more later species descended. | |
| 2.4 | Independent sources (fossils, anatomy, embryology, molecular, biogeography) supporting evolution. | |
| 2.5 | The increase of drug-resistant bacteria through selection when antibiotics are used. | |
| 2.6 | The differential survival and reproduction of individuals with advantageous heritable traits. | |
| 2.7 | The line of evidence based on the distribution of species, explained by ancestry and continental movement. | |
| 2.8 | The line of evidence based on homologous structures such as the pentadactyl limb. |
3. Identify the line of evidence
For each example below, write the matching line of evidence: fossils (F), comparative anatomy (A), comparative embryology (E), biochemical/molecular (M), or biogeography (B) in the Type column. 8 marks
| Type (F/A/E/M/B) | Example |
|---|---|
| Fish, chick and human embryos all develop pharyngeal arches and a post-anal tail | |
| Closely related species have very similar DNA and protein sequences | |
| The pentadactyl limb is shared by humans, whales, bats and cats | |
| Ordered rock sequences contain transitional forms showing change over time | |
| The distribution of marsupials is explained by ancestry and continental movement | |
| A human embryo briefly develops a tail before it disappears | |
| Similar amino acid sequences in the haemoglobin of related mammals | |
| Transitional whale fossils with reduced hind limbs |
4. True or false, with correction
Circle T or F. If the statement is false, write the corrected version on the line below. 8 marks, 1 for T/F, 1 for correction where needed
4.1 Similar early embryos in different vertebrates are evidence of descent from a common ancestor. T / F
4.2 Antibiotics cause individual bacteria to learn to resist the drug during their lifetime. T / F
4.3 When several independent lines of evidence converge on the same conclusion, the case for evolution is stronger than any single line alone. T / F
4.4 Antibiotic resistance arises because resistant bacteria survive treatment and reproduce. T / F
5. Build a concept map
Draw labelled arrows between the five terms below to show how they connect. Each arrow must carry a linking phrase (e.g. “is evidence of”, “is one line of”, “is driven by”). Aim for at least 5 labelled arrows. 5 marks
Supplied terms: comparative embryology • common ancestor • lines of evidence • antibiotic resistance • natural selection.
Q1, Cloze paragraph
In order: comparative embryology • pharyngeal arches • post-anal tail • common ancestor • independent • antibiotic resistance • variation • natural selection.
Q2, Term–definition matches
2.1 comparative embryology • 2.2 pharyngeal arches • 2.3 common ancestor • 2.4 lines of evidence • 2.5 antibiotic resistance • 2.6 natural selection • 2.7 biogeography • 2.8 comparative anatomy.
Q3, Line of evidence answers
E Fish, chick, human embryos • M Similar DNA/protein sequences • A Pentadactyl limb • F Ordered rock sequences • B Distribution of marsupials • E Human embryo tail • M Similar haemoglobin amino acids • F Transitional whale fossils.
Q4, True/False with correction
4.1 True.
4.2 False. Correction: Resistance comes from pre-existing genetic variation. Antibiotics kill susceptible bacteria but the few resistant ones survive and reproduce, this is natural selection, not individual learning.
4.3 True.
4.4 True.
Q5, Sample concept map
Accept any biologically valid linking phrases. A correct map should include arrows such as:
- comparative embryologyis one of the → lines of evidence
- comparative embryologyis evidence of a → common ancestor
- lines of evidenceconverge to support descent from a → common ancestor
- antibiotic resistanceis driven by → natural selection
- antibiotic resistanceis a modern, observable line of → lines of evidence
Award 1 mark per correctly labelled arrow with a valid linking phrase. Maximum 5 marks.