Grade 9 · Science · Unit 1 of 10
Biodiversity & Heredity
Variation, reproduction and genes
What your child practises
Why variety within and between species helps living things survive, how symbiosis works, sexual and asexual reproduction, the basics of DNA, genes and chromosomes, and how people and nature influence which traits are passed on.
Alberta Curriculum learning outcome: Unit A: Biological Diversity · species and niches, variation, how traits are passed on, and what puts diversity at risk
Sample questions
A taste of this unit. In the app, questions change every time and get easier or harder to match your child.
Question 1
One bacterium divides by binary fission every 15 minutes. How many bacteria are there after 45 minutes, starting with one?
answer box
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8
Hint: Each division doubles the number. After 3 divisions: 2 × 2 × 2 = 8.
Question 2
Which is an example of natural selection?
- A breeder crosses two dog breeds
- A gardener clones a rose
- A farmer chooses the largest seeds to plant
- Insects with a resistance to a pesticide survive and pass this trait on
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Insects with a resistance to a pesticide survive and pass this trait on
Hint: In natural selection the environment, not people, determines which individuals survive and reproduce.
Question 3
Which best describes the relationship between DNA, genes and chromosomes?
- Chromosomes are made of DNA, and genes are sections of DNA that carry instructions for traits
- Genes are made of chromosomes, and DNA is a trait
- DNA is a gene made of chromosomes
- Chromosomes are found only in sex cells
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Chromosomes are made of DNA, and genes are sections of DNA that carry instructions for traits
Hint: DNA is the molecule that stores the instructions. A gene is a short section of it. Long strands of DNA make up chromosomes.
Question 4
A dog body cell has 78 chromosomes. How many chromosomes are in one of its sex cells (gametes)?
- 39
- 78
- 156
- 41
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39
Hint: Meiosis halves the number of chromosomes, so a sex cell has 78 ÷ 2 = 39. When two sex cells join, the full number is restored.
Question 5
What is a niche?
- the number of animals in a herd
- a place where only plants grow
- the role a species plays in its ecosystem, including what it eats and where it lives
- the smallest part of a cell
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the role a species plays in its ecosystem, including what it eats and where it lives
Hint: A niche is a species' "job" in an ecosystem: its food, home and relationships with other living things.
Question 6
Which is true about a dominant trait?
- It is always better for survival
- It can never be passed on
- It shows in the offspring even when only one parent passes it on
- It is always the most common trait
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It shows in the offspring even when only one parent passes it on
Hint: Dominant and recessive traits only partly explain variation: many traits are controlled by more than one gene.