End of Term 1 Exam Coverage

Section 1: Ecosystem Structure & Organization

This section breaks down the fundamental building blocks of an ecosystem. You'll learn to identify the living (**biotic**) and nonliving (**abiotic**) parts, and understand how life is organized into different levels, from a single organism to the entire biosphere.

LO 1: Parts of an Ecosystem

An ecosystem is made of two main components that interact with each other:

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Biotic Factors:
All the living or once-living parts, such as plants, animals, bacteria, and fungi.
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Abiotic Factors:
All the nonliving parts, such as water, air, sunlight, soil, and temperature.

LO 21: Levels of Organization

Living things are organized in hierarchical levels, from smallest to largest:

Organism: A single living thing.

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Population: A group of the same species.

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Community: All the different populations.

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Ecosystem: The community + abiotic factors.

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Biome: A large region with similar climate.

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Biosphere: All parts of Earth where life exists.

Section 2: Energy Flow & Chemical Reactions

This section covers the engine of life. You'll explore the two most important chemical reactions—**photosynthesis** (how energy is captured) and **cellular respiration** (how energy is released). You'll also learn how this energy flows in one direction through an ecosystem.

LO 2, 3, 4, 24: Photosynthesis vs. Cellular Respiration

These two reactions are opposites, forming a cycle. One creates food, the other releases energy from food. [Image of photosynthesis and cellular respiration cycle]

Photosynthesis 🌿 (Producers)

Done by Producers (plants) to create their own food (glucose) using sunlight.

6CO₂ + 6H₂O + Sunlight → C₆H₁₂O₆ + 6O₂

Carbon Dioxide + Water + Energy → Glucose + Oxygen

Cellular Respiration ⚡ (All Organisms)

Done by ALL Organisms (plants and animals) to release usable energy (ATP) from glucose.

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy (ATP)

Glucose + Oxygen → Carbon Dioxide + Water + Energy

LO 5, 6, 7: The Flow of Energy

Energy flows in one direction through an ecosystem. Food chains and food webs show this flow.

Producers: Make their own food (e.g., plants).
Consumers: Eat other organisms (e.g., animals).

The 10% Rule

When energy moves from one trophic level (feeding level) to the next, only about 10% of the energy is transferred. The other 90% is lost as heat. This is why there are fewer top predators.

Visualizing the 10% Rule

This chart shows the energy available at one trophic level.

Section 3: Cycling of Matter

Unlike energy, matter (like water, carbon, and nitrogen) is continuously **recycled** within an ecosystem. This section explores the key processes of the major cycles.

The Water Cycle 💧

The continuous movement of water on, above, and below Earth's surface.

Evaporation: Liquid water turns into gas (water vapor).
Condensation: Water vapor cools and turns into liquid (clouds).
Precipitation: Water falls back to Earth (rain, snow).
Collection/Runoff: Water flows over land or collects in oceans.

The Carbon Cycle ⚫

Carbon, the basis of life, cycles between the air, land, water, and living things.

Photosynthesis: Takes CO₂ from the air.
Respiration: Releases CO₂ back into the air.
Decomposition: Releases carbon from dead organisms.
Human Impact: Burning fossil fuels releases large amounts of stored CO₂.

The Nitrogen Cycle 🧬

Nitrogen is needed for DNA and proteins. This cycle relies heavily on **bacteria**.

Nitrogen Fixation: Bacteria change unusable nitrogen gas (N₂) into forms plants can absorb.
Assimilation: Plants absorb nitrogen compounds.
Decomposition: Bacteria return nitrogen to the soil.

Section 4: Patterns of Interactions

No organism lives in isolation. This section explores the five main ways organisms in a community interact with each other, from fighting for food (**competition**) to forming close, long-term relationships (**symbiosis**).

Competition

Organisms fight over the same limited resources (food, water, space).

Example: Two trees competing for sunlight.

Predation

One organism (the predator) hunts and eats another (the prey).

Example: A hawk catching and eating a snake.

Symbiosis

A close, long-term relationship between two different species. There are three types:

1. Mutualism (+, +)

Both species **benefit** from the relationship.

Example: A bee gets nectar, and the flower gets pollinated.

2. Commensalism (+, 0)

One species **benefits**, and the other is **not affected**.

Example: Barnacles on a whale get a ride and food.

3. Parasitism (+, -)

One species (the parasite) **benefits**, and the other (the host) is **harmed**.

Example: A tick feeding on a dog's blood.

Section 5: Ecosystem Changes & Populations

Ecosystems are not static; they are always changing. This section explains how changes to physical or biological components can affect populations, and how we analyze the availability of resources to understand these effects.

LO 10-19: Changes to Components

Changes in an ecosystem can be physical (abiotic) or biological (biotic).

Physical Changes:

Climate change
Floods or fires
Habitat destruction

Biological Changes:

Invasive species
Disease outbreak
Change in predators

Limiting Factors: These changes act as limiting factors, restricting how large a population can grow. For example, a drought limits water, causing populations to shrink.

Resilience: The ability of an ecosystem to stay balanced and recover quickly after repeated disturbances (like a fire).

LO 23: Analyzing Resource Data

When you analyze data (like graphs or tables) about populations, you should look for evidence of resource availability:

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High Resource Availability:
Populations will be large, healthy, and growing.
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Low Resource Availability:
Populations will decline (die off) or show lower birth rates. This is evidence of a limiting factor.

Section 6: Biodiversity

Biodiversity is the variety of life in an area. High biodiversity means an ecosystem is healthier and more **resilient** to change. This section covers how we measure, maintain, and evaluate biodiversity.

LO 18: Measuring Biodiversity

Scientists count the number and variety of species using methods like:

Quadrat Sampling: Using a square frame to count organisms in a small area, then estimating the total.
Transect Lines: Measuring species along a straight line to see how the community changes.

LO 20: Maintaining Biodiversity

We must protect biodiversity to keep ecosystems stable. Methods include:

**Protecting Habitats:** Creating national parks and marine protected areas.
**Sustainable Practices:** Regulating fishing/hunting and reducing pollution.
**Educating the Public.**

LO 22: Evaluating Biodiversity

Some ecosystems naturally have more biodiversity than others. The biggest threats are climate change and human habitat destruction.

Biodiversity Level	Ecosystem Examples	Characteristics
High Biodiversity	Tropical Rainforests, Coral Reefs	Located near the equator. Warm, stable temperatures, high rainfall, abundant sunlight.
Low Biodiversity	Deserts, Arctic Tundra	Extreme conditions (very hot, very cold, or very dry).

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