Biology›Year 11›Module 3›Checkpoint 1

Checkpoint Quiz 1, Biodiversity & Phylogenetics

Covers biodiversity levels and phylogenetic trees.

Biodiversity & Phylogenetics 6 MC · 2 Short Answer 14 marks total

Lesson Summaries

L01 What is Biodiversity?

Biodiversity is the variety of life on Earth across genetic, species and ecosystem levels. Genetic diversity refers to allele variation within a population, species diversity depends on richness and evenness, and ecosystem diversity refers to the variety of habitats, communities and ecological processes. Biodiversity matters because it supports resilience, ecological stability and future biological resources.

genetic diversityspecies richnessevennessecosystem diversity

L03 Phylogenetic Trees

Phylogenetic trees represent evolutionary relationships based on common ancestry, not just physical similarity. Key features include the root, nodes, branches, tips and sister groups. Molecular evidence can resolve relationships that morphology alone obscures, and parsimony favours the most likely tree requiring the fewest evolutionary changes.

nodesister groupscommon ancestryparsimony

MC Score

0 / 6

Aim for at least 5/6 before moving on.

Multiple Choice, 6 marks

One mark each. Choose the best answer.

Biodiversity

1. Which option correctly matches the biodiversity level with its description?

A Species diversity = variation in alleles within a population
B Genetic diversity = variation in alleles within a species or population
C Ecosystem diversity = the number of species in one community
D Genetic diversity = number of species present in an area

2. A forest contains many species, but one species makes up almost all individuals. Which conclusion is most accurate?

A It must have high species diversity because it has many species
B It may have lower species diversity than expected because evenness is low
C It proves the forest has high genetic diversity
D It demonstrates high ecosystem diversity
Phylogenetic Trees

3. What does a node on a phylogenetic tree represent?

A A living species between two branches
B A divergence point from a common ancestral lineage
C The age of the oldest fossil in the group
D The current taxon at the end of a branch

4. Sister groups are best defined as:

A Two lineages sharing the most recent common ancestor
B Any two taxa drawn closest together on the diagram
C The pair connected most directly to the root
D Any two organisms from the same environment

5. What is the main advantage of molecular evidence in phylogenetic studies?

A It proves morphology is never useful
B It can resolve relationships hidden by misleading physical similarity
C It is only useful when organisms already look identical
D It only works if a fossil record exists

6. Parsimony suggests that the best-supported phylogenetic tree is usually the one that:

A Has the shortest branches when drawn
B Requires the fewest evolutionary changes to explain the evidence
C Was proposed first historically
D Proves evolution always proceeds in the simplest way in nature

Short Answer, 8 marks

Use these to check whether you can explain and evaluate, not just recognise definitions.

7. Distinguish between genetic diversity, species diversity and ecosystem diversity using one example for each. 4 MARKS

1 mark: genetic | 1 mark: species | 1 mark: ecosystem | 1 mark: correct examples

8. Explain why visual similarity alone is not always enough to classify organisms accurately. In your answer, refer to phylogenetic trees or molecular evidence. 4 MARKS

1 mark: judgement | 1 mark: limitation of visual similarity | 1 mark: role of phylogenetic/molecular evidence | 1 mark: coherent explanation

  • 1. BGenetic diversity refers to allele variation within a species or population.
  • 2. BHigh richness can still be paired with low evenness, reducing species diversity.
  • 3. BNodes represent divergence from a common ancestral lineage.
  • 4. ASister groups share the most recent common ancestor.
  • 5. BMolecular evidence can resolve misleading visual similarity.
  • 6. BParsimony prefers the tree requiring the fewest changes.

7. Genetic diversity is variation in alleles within a population, such as different immune-response alleles in a koala population. Species diversity refers to the number of species present and how evenly they are distributed, such as a woodland with many bird species present in balanced numbers. Ecosystem diversity refers to the variety of habitats, communities and processes, such as a coastal region containing mangroves, estuaries, reefs and seagrass meadows.

8. Visual similarity alone is not always enough because unrelated organisms can evolve similar features through convergent evolution. Phylogenetic trees aim to represent common ancestry, not just resemblance. Molecular evidence such as DNA sequence comparison can reveal relationships that appearance alone may hide or distort, making classification more reliable.

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