Explaining Change: Genetics, Evolution and Reactions
One big idea links biology and chemistry: change. Learn how genes and variation are inherited, how natural selection changes a species over time, and how substances change in chemical reactions.
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One idea: change
Biology and chemistry can feel like separate worlds, but this topic joins them with a single idea: **change**, and what causes it. Genes and **inheritance** explain how features pass on. **Natural selection** explains how a whole species changes over time. And **chemical reactions** explain how substances change into new ones. This module looks at all three.
Words to know
Four words span this whole topic, from genes to reactions.
Match the genetics word
- Variation
- Gene
- DNA
- Allele
- Differences between individuals
- A section of DNA coding for a feature
- The molecule that carries genetic information
- A version of a gene
Dominant or recessive?
A dominant allele shows in the offspring whenever it is present. When does a recessive allele show?
- Only when both alleles are recessive
- It always shows, like a dominant one
- It never shows at all
- Only in male offspring
Physical or chemical change?
Not every change makes a new substance. This is a key difference in chemistry.
Match the rate factor
- Higher temperature
- Higher concentration
- Smaller pieces
- Adding a catalyst
- Particles move faster and collide more often
- More particles in the same space to collide
- More surface area for collisions
- Speeds it up without being used up
The link is cause and effect
Whether it is a gene passing on, a species evolving, or substances reacting, this topic is about change and what causes it. In your answers, always name the cause of the change, not just the change itself.
Complete the summary
Differences between individuals are called _____. Genes are carried on _____. Over many generations, _____ selection changes a species. A change that makes a new substance is a chemical _____. Heating a reaction usually makes it go _____.
Speeding up a reaction
Which of these would speed up a chemical reaction? Choose all that apply.
- Raising the temperature
- Increasing the concentration
- Adding a catalyst
- Cooling the mixture down
- Using larger lumps instead of powder
Find the chemical changes
An interactive activity.
How natural selection works
An interactive activity.
Energy in reactions
A reaction that transfers energy to the surroundings and makes them warmer is described as what?
- Exothermic
- Endothermic
- Physical
- Reversible
Change in a beetle population
An interactive activity.
Your turn
An interactive activity.