Unit 4 Biology Final Review

Here’s your cleaned-up and corrected version of the Unit 4 study guide, with proper spelling, grammar, and formatting for clarity:

Unit 4 – Key Concepts: Intro to Ecology & Energy Flow Through Ecosystems

What is Ecology?

• Ecology is the scientific study of living things and how they interact with their environment.

Ecosystems

• Ecosystems involve the interaction between living (biotic) and nonliving (abiotic) factors in an environment.

• Scientists study ecosystems to assess the abundance and behavior of organisms like plants and animals.

Key Tasks of Ecologists

• Collect data on species populations.

• Study relationships between different organisms and their environments.

• Monitor ecosystem health and changes over time.

• Conduct fieldwork to observe plant and animal behavior.

Work Environment

• Often based in natural habitats: forests, oceans, wetlands, etc.

• May also work in labs to analyze data.

• Use tools such as cameras and GPS systems.

Employment Settings

• Government Agencies: environmental monitoring, policy-making, protecting endangered species.

• Conservation Charities: wildlife protection, habitat restoration, promoting sustainable practices.

• Research Institutions: academic research on ecological systems, conservation strategies, ecosystem management.

Levels of Organization in Ecology

1. Organism – A single individual in a given area.

2. Population – A group of individuals of the same species in the same area.

3. Community – Different populations living and interacting in an area.

4. Ecosystem – All organisms living in a place, plus their physical environment.

5. Biome – A group of ecosystems that share similar climates and organisms.

6. Biosphere – The part of Earth where life exists.

Niche

• Refers to the unique living arrangements or "lifestyle" of an organism.

• Includes:

  • Food source/nutrients

  • Nesting site

  • Time of day active

  • Interactions with other species

Types of Competition

1. Interspecific Competition

• Between different species

• Happens when species with similar niches compete for the same resources.

Examples:

• Sharks and dolphins competing for the same fish.

• Woodpeckers and squirrels competing for tree nesting sites.

2. Intraspecific Competition

• Within the same species

• Individuals compete for limited resources like food, mates, or shelter.

Examples:

• Two male birds competing for a female.

• Emperor penguins competing for nesting spots.

Key Points on Competition

• Similar niches = more competition.

• Limited resources trigger competition.

• Competition can lead to:

  • Exclusion – one species may be forced out.

  • Adaptation – species may evolve different behaviors or niches.

Predation

• Predator eats prey.

Energy Flow Through Ecosystems

Ecosystem Energy Roles

• Energy roles depend on how organisms obtain energy and interact with others.

Producers (Autotrophs)

• Use sunlight as the main energy source.

• Make their own food through photosynthesis.

• Include: plants, algae, some bacteria.

• Role: First to produce energy in the food chain.

Consumers (Heterotrophs)

• Must consume other organisms for energy.

Types:

• Herbivores – Eat plants

• Carnivores – Eat animals

• Omnivores – Eat plants and animals

• Scavengers – Eat dead animals

• Decomposers – Break down dead matter (fungi, bacteria)

Food Chains

• Show one-way energy flow: Producers → Consumers

• Arrows show the direction of energy flow, not who eats whom.

Trophic Levels Example:

• Producer → Primary Consumer → Secondary → Tertiary → Quaternary

Trophic Levels

• Each step in a food chain/web is called a trophic level.

• 1st level = Primary Producers

Energy Pyramid

• Shows energy loss between trophic levels.

• Only 10% of energy is passed to the next level.

• Energy is lost as heat, movement, and growth.

Food Web

• Made of many interconnected food chains.

• Shows all feeding relationships in an ecosystem.

• Arrows represent the flow of energy.

Be able to identify:

• Producers

• Primary, Secondary, Tertiary Consumers

• Herbivores, Omnivores, Carnivores

Reflection Questions

• Are organisms always competing?

• Is every relationship competitive?

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