Living Systems and Adaptations

MYP Unit Framework

Key Concept: SYSTEMS Related Concepts: Adaptation, Environment, Function Global Context: Globalization and Sustainability (How are living systems connected and how can we protect them?) Statement of Inquiry: Living organisms are complex systems adapted to their environments through evolutionary processes.

Inquiry Questions

ATL Skills

• Thinking: Analyse relationships within ecosystems; understand systems thinking
• Research: Conduct field studies; collect and interpret ecological data
• Communication: Draw food webs; present findings from ecological investigations
• Social: Collaborate on fieldwork and group projects
• Self-Management: Organise equipment and data for field studies

1. Levels of Ecological Organisation

From Individual to Biosphere

1. Organism: A single living individual
2. Population: A group of the same species living in the same area
3. Community: All the populations of different species living in the same area
4. Ecosystem: The community AND the non-living environment (soil, water, air, sunlight)
5. Biome: A large region with similar climate and characteristic organisms (tropical rainforest, desert, tundra)
6. Biosphere: All of Earth's ecosystems combined — the zone of life on Earth

Components of an Ecosystem

Biotic Factors (Living):

• Producers (plants, algae)
• Consumers (herbivores, carnivores, omnivores, decomposers)
• Decomposers (bacteria, fungi)

Abiotic Factors (Non-Living):

• Sunlight
• Temperature
• Water and moisture
• Soil type and pH
• Oxygen concentration
• Nutrients

2. Adaptations

What Are Adaptations?

Adaptations are characteristics that help an organism survive and reproduce in its environment. Adaptations develop over many generations through natural selection.

Types of Adaptations

Structural Adaptations: Physical features of the body.

• Examples: Camouflage (polar bear's white fur), sharp teeth (carnivores), long roots (desert plants), thick fur (arctic animals)

Behavioural Adaptations: Actions or patterns of behaviour.

• Examples: Migration (birds flying south for winter), hibernation (bears), hunting in packs (wolves), nocturnal activity (bats)

Physiological Adaptations: Internal body processes.

• Examples: Venom production (snakes), water storage (cacti), producing antifreeze proteins (arctic fish), bioluminescence (deep-sea creatures)

Case Studies in Adaptation

Desert Adaptations: Camel — hump stores fat, not water; nostrils close to prevent sand; thick fur reflects sunlight; wide feet for walking on sand.

Arctic Adaptations: Polar bear — white fur for camouflage; thick layer of blubber; large feet for walking on snow; excellent sense of smell.

Aquatic Adaptations: Fish — gills for extracting oxygen from water; fins for movement; swim bladder for buoyancy; streamlined body for reducing drag.

3. Energy Flow in Ecosystems

Food Chains

A food chain shows the flow of energy from one organism to another:

Example: Sun → Grass → Rabbit → Fox → Decomposer

Trophic Levels

• Producers (Level 1): Convert sunlight into energy through photosynthesis (plants, algae)
• Primary Consumers (Level 2): Eat producers (herbivores)
• Secondary Consumers (Level 3): Eat primary consumers (carnivores)
• Tertiary Consumers (Level 4): Eat secondary consumers (top predators)

Food Webs

A food web is a network of interconnected food chains. Most organisms eat and are eaten by multiple species, making food webs more realistic than simple food chains.

Why Food Webs Matter: Food webs show the complex interdependence of species. Removing one species can have cascading effects throughout the web.

Energy Pyramids

Only about 10% of energy at one trophic level is passed to the next. The rest is used for life processes (respiration, movement, growth) or lost as heat.

This explains why:

• There are fewer organisms at higher trophic levels
• Top predators are rare
• Food chains rarely have more than 4-5 levels

4. Nutrient Cycles

The Carbon Cycle

Carbon moves through ecosystems via:

1. Photosynthesis: Plants take CO₂ from the atmosphere
2. Respiration: All organisms release CO₂
3. Decomposition: Decomposers break down dead organisms, releasing CO₂
4. Combustion: Burning fossil fuels releases CO₂
5. Fossilisation: Over millions of years, dead organisms become fossil fuels

The Nitrogen Cycle

Nitrogen is essential for proteins and DNA. Most organisms cannot use nitrogen gas directly.

1. Nitrogen Fixation: Bacteria convert N₂ into ammonia (NH₃)
2. Nitrification: Bacteria convert ammonia into nitrates (usable by plants)
3. Assimilation: Plants absorb nitrates through roots
4. Consumption: Animals eat plants and obtain nitrogen
5. Decomposition: Decomposers return nitrogen to the soil
6. Denitrification: Bacteria convert nitrates back to N₂ gas

5. Human Impact on Ecosystems

Biodiversity Loss

Biodiversity is the variety of life in an ecosystem. Human activities threaten biodiversity through:

• Habitat Destruction: Deforestation, urbanisation, agriculture
• Pollution: Chemicals, plastics, light, and noise pollution
• Overexploitation: Overfishing, poaching, hunting
• Invasive Species: Non-native species outcompeting native species
• Climate Change: Altered temperatures and weather patterns

Conservation

• Protected Areas: National parks, wildlife reserves, marine protected areas
• Restoration Ecology: Rehabilitating damaged ecosystems
• Captive Breeding: Breeding endangered species in captivity for reintroduction
• Sustainable Practices: Reducing consumption, using renewable resources
• International Agreements: CITES (Convention on International Trade in Endangered Species)

6. Practical Investigations

Investigation 1: Quadrat Sampling

Use quadrats to sample plant populations in two different areas (e.g., mown grass vs. unmown grass). Calculate species frequency and diversity. Compare the two areas.

Investigation 2: Investigating Decomposition

Compare the rate of decomposition under different conditions (temperature, moisture, presence of soil organisms). Observe over 2-4 weeks.

Investigation 3: Habitat Study

Choose a small habitat (pond, tree, garden). Identify as many species as possible. Draw a food web showing their relationships. Describe adaptations of at least three organisms.

Summative Assessment

Task: Ecological investigation report (800-1000 words) OR research presentation on a conservation issue.

Criteria:

• A: Knowing and Understanding — Explain ecological concepts accurately
• B: Inquiring and Designing — Design and conduct an ecological investigation
• C: Processing and Evaluating — Process data; evaluate methods and limitations
• D: Reflecting on the Impacts of Science — Discuss human impact and conservation

Option 1: Conduct a habitat study. Describe the ecosystem, identify organisms, create a food web, and discuss adaptations.

Option 2: Research an endangered species. Describe its adaptations, explain why it is endangered, and evaluate conservation efforts.

Option 3: Investigate the impact of an environmental factor (e.g., light, moisture) on the distribution of a plant species in your local area.

Formative Assessment

• Ecological organisation diagram: label levels from organism to biosphere
• Adaptation matching activity: match organisms to their adaptations
• Food web construction: create a food web from a given list of organisms
• Energy pyramid calculations: 10% rule problems
• Case study analysis: impact of an invasive species
• Conservation poster: present an endangered species and conservation strategies

Interdisciplinary Connections

• Geography: Biomes of the world; human-environment interaction
• Mathematics: Population sampling; calculating biodiversity indices
• Art: Scientific illustration of organisms and their adaptations
• Environmental Science: Climate change impacts on ecosystems; sustainability

Service as Action

• School Garden: Create or maintain a native plant garden. Observe the organisms it attracts. Document the ecosystem that develops.
• Awareness Campaign: Research a local conservation issue. Create information materials and present them at a school assembly or community event.

IB Learner Profile

• Inquirers: Investigate living systems through observation and field study
• Knowledgeable: Understand ecosystems, adaptations, and human impact
• Caring: Develop concern for the natural world and species conservation
• Principled: Make environmentally responsible choices

Self-Test

1. List the levels of ecological organisation from smallest to largest.
2. What is the difference between biotic and abiotic factors? Give three examples of each.
3. Name and describe THREE types of adaptations with examples.
4. How does a polar bear's white fur help it survive?
5. Draw a food chain with four trophic levels.
6. Explain why only about 10% of energy passes from one trophic level to the next.
7. Describe the carbon cycle. Name FOUR processes involved.
8. Why is nitrogen important for living organisms? How do they obtain it?
9. List FIVE human activities that threaten biodiversity.
10. How can conservation efforts help protect ecosystems?

This unit aligns with IB MYP Sciences guide, developed for Year 3 (Class 8) students.