Conserving and restoring the environment, and the factors that control the growth and survival of populations, including humans.
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.
Why did a population of sea urchins explode, then crash? The answer is on the growth curve.
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.
Protection and sustainable management of natural resources.
Repairing damaged ecosystems, e.g. replanting mangroves; reafforestation = replanting cut forest.
Protected areas, legislation (quotas, closed seasons, net sizes), captive breeding, seed banks, controlling invasives, education, reforestation.
Lag → exponential → stationary (carrying capacity) → decline.
Maximum population an environment can support long-term.
Food, water, space, shelter, disease, predation, competition, pollution.
Over 8 billion (UN, 2022). Death rates fell with medicine and sanitation; birth rates fall with contraception and education.
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.
| Time (h) | 0 | 2 | 4 | 6 | 8 | 10 | 12 |
|---|---|---|---|---|---|---|---|
| Yeast cells (thousands per cm³) | 2 | 4 | 12 | 40 | 70 | 78 | 80 |
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.
| Method | How it helps | Example |
|---|---|---|
| Protected areas | Habitats kept free from development and over-harvesting | Marine parks and national parks across the region |
| Laws and closed seasons | Limit hunting and fishing while animals breed | Closed seasons for spiny lobster and turtles |
| Captive breeding / head-starting | Young raised safely, then released | Jamaican iguana raised at Hope Zoo, Kingston |
| Restoration (replanting) | Rebuilds damaged habitats | Mangrove and coral replanting projects |
| Seed banks | Store seeds of rare plants for the future | National and international seed banks |
| Education | People understand and support protection | School and community programmes |
Conservation protects what is still there; restoration repairs what has been damaged.
The four phases: Lazy Lions Stay Down — Lag, Log, Stationary, Death.
The Jamaican iguana was thought to be extinct until it was rediscovered in the Hellshire Hills in 1990. Head-starting (raising young safely before release) and protection of its dry-forest habitat have helped it survive.
Find your country’s census population for the last five censuses. Plot them on a line graph. Which phase of the growth curve does your country seem to be in?
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 (13 marks in total). Your answers are saved on this device.
Question 1 [5 marks]
Fish populations on Caribbean coral reefs are threatened by predation and pollution.
(a) Define the term “conservation” as used in biology. [1]
(b) Explain TWO methods of conservation that could minimise these threats. [4]
Question 2 [8 marks]
A few goats were introduced to a small island with no predators. Their numbers were recorded for 20 years.
(a) Sketch/describe the expected growth curve and name its FOUR phases. [4]
(b) Explain why the population stopped increasing. [2]
(c) Suggest TWO factors that account for rapid human population growth in the last century. [2]
Find these in your own past-paper booklets for extra timed practice. The practice above is adapted from them.