What a species is, how new species form, Darwin’s theory of natural selection with Caribbean and modern examples, and natural vs artificial selection.
5 narrated scenes. Press play, listen and read along — the points appear as they are explained. Use ‹ Prev / Next › or the scene bar to jump to any scene.
Anole lizards on different Caribbean islands look remarkably alike — yet they evolved separately. How?
Narration uses your device’s built-in voice. No sound? Switch to “Captions only” — the captions advance on their own.
Copy these into your notebook in your own words — that is how they stick.
Organisms that can interbreed under natural conditions to produce fertile offspring.
Variation → overproduction → competition → survival of best adapted → reproduction → change in allele frequency.
Peppered moth, antibiotic resistance, pesticide resistance, Galapagos finches, Caribbean anoles.
Geographical isolation (allopatric) or reproductive isolation (sympatric) → populations diverge → cannot interbreed.
Humans breed organisms with desired traits; faster; reduces variation.
Adaptation to environment; biodiversity; survival of species.
Slow; less-adapted individuals die; can produce resistant pests/pathogens that harm humans.
The kind of support a teacher gives after the lesson: worked examples to attempt first, a board illustration, key terms, common misconceptions and memory aids.
Try it in your notebook first, then reveal the solution one step at a time.
Try it in your notebook first, then reveal the solution one step at a time.
Write these five ideas in order and you have the core of any natural selection answer.
Natural selection in five words: Variation, Over-production, Competition, Survival, Reproduction — “VOCS-R”.
Aedes aegypti mosquitoes in many Caribbean countries have become resistant to some common insecticides. Public health teams test for resistance and switch between insecticides — natural selection is a real problem in disease control.
Scatter 20 green and 20 brown paper “insects” on a lawn. Give a friend 30 seconds to pick up as many as they can. Which colour survived better? Repeat on bare soil.
3 quick games on this lesson. Earn XP and badges as you play — your best score for each game is saved. Games are for practice and do not change your exam readiness.
8 items modelled on real CSEC Paper 1 questions. Choose one answer for each, then check. Aim for 80% or better.
Write full answers, then reveal the mark scheme and tick the points you earned (24 marks in total). Your answers are saved on this device.
Question 1 [9 marks]
Natural selection and artificial selection.
(a) Outline Darwin’s theory of natural selection. [2]
(b) Explain why the development of antibiotic resistance in bacteria is an example of natural selection. [2]
(c) Suggest TWO ways artificial selection benefits a farmer. [2]
(d) Toxic toads were introduced to an island of iguanas. Many iguanas that ate them died; years later adult tail length had increased by 10%. Suggest THREE reasons. [3]
Question 2 [15 marks]
Species and speciation.
(a) Using TWO examples, define the term “species”. [4]
(b) State TWO ways speciation occurs and explain how each leads to a new species. [6]
(c) Outline THREE advantages and TWO disadvantages of natural selection. [5]
Find these in your own past-paper booklets for extra timed practice. The practice above is adapted from them.