IB Diploma · Biology A3.1
IB Biology A3.1: Div. of Org. — Practice Questions & Answers
IB Biology A3.1 Diversity of organisms notes: defining species, naming with binomial nomenclature, variation, chromosome differences, and measuring diversity.
Here are 10 practice questions with full answers and explanations.
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Practice questions with answers
1
Multiple choice
Which human species is the only surviving one today?
- Homo sapiens
- Homo neanderthalensis
- Homo floresiensis
- Denisovans
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WhyHomo sapiens is the only surviving human species, all others in the genus having gone extinct.
2
Multiple choice
What is a defining feature of all living organisms?
- Variation
- Uniformity
- Immutability
- Stasis
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WhyVariation among individuals is a defining feature of all living organisms and the raw material for evolution.
3
Multiple choice
Who developed the modern system for classifying living organisms?
- Carl Linnaeus
- Charles Darwin
- Gregor Mendel
- Alfred Hershey
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WhyCarl Linnaeus devised the modern hierarchical classification system and binomial naming of organisms.
4
Multiple choice
What system names species using their genus and species names?
- Binomial nomenclature
- Taxonomic hierarchy
- Phylogenetic tree
- Cladistics
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WhyBinomial nomenclature names each species with a two-part Latin name comprising its genus and species.
5
Multiple choice
What is the first part of a binomial name?
- Genus
- Species
- Family
- Order
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WhyThe first part of a binomial name is the genus, which is capitalised.
6
Multiple choice
What is the second part of a binomial name?
- Species
- Genus
- Family
- Order
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WhyThe second part of a binomial name is the species (specific) epithet, written in lowercase.
7
Multiple choice
What are infertile offspring between two different species called?
- Hybrids
- Mutants
- Clones
- Variants
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WhyHybrids are offspring of two different species and are often infertile due to mismatched chromosomes.
8
Multiple choice
Which hybrid is produced by breeding a horse and a donkey?
- Mule
- Liger
- Zebroid
- Grolar bear
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WhyA mule is the infertile hybrid produced by crossing a female horse with a male donkey.
9
Multiple choice
What are the DNA-containing structures in the nucleus of eukaryotic cells called?
- Chromosomes
- Genes
- Plasmids
- Operons
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WhyChromosomes are the DNA-containing structures within the nucleus of eukaryotic cells.
10
Multiple choice
How many chromosomes do human diploid cells have?
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WhyHuman diploid cells contain 46 chromosomes, arranged as 23 homologous pairs.
Key terms in Div. of Org.
Species: A group of organisms that can interbreed and produce fertile offspring (biological species concept).
Biological species concept: The definition of a species based on the ability to interbreed and produce fertile offspring.
Binomial nomenclature: The two-part Latin naming system: an italicised, capitalised genus name followed by a lower-case species name.
Hybrid: The offspring of a cross between two different species, often sterile, as in the mule.
Continuous variation: Variation showing a smooth range of values, influenced by many genes and the environment, such as height.
Discrete variation: Variation falling into distinct categories with no intermediates, usually controlled by one or few genes, such as blood groups.
Species richness: The number of different species present in a community.
Evenness: How equally individuals are distributed among the species in a community.
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