BIOLOGY · Stage 8 · Chapter 8: Weather and Climate
Biology Stage 8 Comprehensive Review
5 min read 5 parts Lesson 6 of 6
Lesson summary
Biology Stage 8 Comprehensive Review — Alhussan International Academy — Biology (Stages 7–9) notes: Bring together the main Stage 8 biology ideas on diet, health, movement, ecosystems and climate.Balanced diet — it supplies carbohydrates, fats, proteins, vitamins, minerals, fibre…
- Health between countries
- Correlation
- Stronger claims
- Practical work
- Synovial joints
- Persistent pesticides
Section 1 of 5Diet, health and disease
- Balanced diet
- it supplies carbohydrates, fats, proteins, vitamins, minerals, fibre and water.
- Protein is for growth and repair, calcium for strong bones and iron for haemoglobin.
- Smoking
- it introduces nicotine, tar and carbon monoxide.
- Nicotine is addictive, tar causes cancer and damages cilia, and carbon monoxide reduces oxygen transport.
- Non-smokers usually have a larger lung capacity than smokers because their lungs are healthier.
- Health between countries
- it varies with clean water, healthcare, education and income.
Section 2 of 5Evidence and scientific method
- Correlation
- it does not prove cause.
- Stronger claims
- large representative samples, control groups, repeated trials, a mechanism and peer review.
- Practical work
- vary one factor, keep others constant, take repeat readings, calculate means and consider anomalies.
- In a lung capacity test, use the same size of balloon and the same breath instructions for every person.
Section 3 of 5Movement
- Skeleton
- it supports and protects the body, allows movement, makes blood cells and stores minerals.
- Synovial joints
- they contain cartilage and synovial fluid and are held by ligaments.
- Muscles
- they are joined to bones by tendons and work in antagonistic pairs such as biceps and triceps.
- Muscles only pull.
Section 4 of 5Ecology and environment
- Ecosystem
- a community of organisms together with its physical environment.
- Food webs
- they show energy transfer from producers to consumers, with losses at each level.
- Persistent pesticides
- they accumulate in food chains.
- Invasive species
- they disrupt ecosystems by competing with native species.
- Conservation
- protected areas, breeding programmes and seed banks.
- Sampling
- quadrats and transects measure populations and distribution.
- Population estimate = mean per quadrat × number of quadrats that fit in the area.
- More worm casts are found where soil is loose and rich in compost than in trampled soil.
Section 5 of 5Weather, climate and evidence
- Weather changes daily, while climate is the long-term average.
- Greenhouse gases absorb infrared radiation, and human emissions of carbon dioxide and methane enhance warming.
- Proxy records
- ice cores, tree rings and bog pollen show natural cycles and the unusually rapid recent change.
- Linked effects
- deforestation affects climate, biodiversity and soil together.
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