Living World Cheat Sheet

Key Definitions

• Biodiversity: Variety of life forms in an ecosystem. ✅

• Ecosystem: Community of living organisms interacting with their environment. ✅

• Habitat: Natural environment where an organism lives. ✅

• Niche: Role of a species in its ecosystem. ✅

Important Concepts

Levels of Biological Organization

• Cell: Basic unit of life. ✅

• Tissue: Group of similar cells performing a function. ✅

• Organ: Structure made of tissues working together. ✅

• Organ System: Group of organs performing a specific function. ✅

• Organism: Individual living entity. ✅

Ecological Relationships

• Predation: One organism eats another. ✅

• Mutualism: Both species benefit. ✅

• Commensalism: One benefits, the other is unaffected. ✅

• Parasitism: One benefits at the expense of the other. ✅

Key Formulas

• N: Total population size (unknown)

• n: Number of marked individuals in recapture

• N: Total captured in recapture

Common Mistakes to Avoid

Common Mistake: Confusing habitat with niche; habitat is where an organism lives, niche is how it lives.

Memory Tricks

Tip: "MNEUMONIC" — Mutualism, Niche, Ecosystem, Union, Microorganisms, Organism, Natural selection, Interdependence, Community.

Key Diagrams

Ecosystem Structure:
   +------------------+
   |   Ecosystem      |
   | +--------------+ |
   | |   Community  | |
   | | +----------+ | |
   | | | Population | | |
   | | +----------+ | |
   | +--------------+ |
   +------------------+