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2.1Ecology

Ecosystem organization — EST 2 Biology Revision Notes & Topical Questions

5 min read 7 parts Lesson 1 of 8 2 quizzes

📚 EST 2 Biology Hub / Topical Revision
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Curriculum Equation Key قوانين الرقم الهيدروجيني والاتزان الأيوني - pH & Acid-Base Equilibrium FormulasFast Exam Solution
pH = -log[H⁺] | pOH = -log[OH⁻] | pH + pOH = 14 | [H⁺][OH⁻] = 10⁻¹⁴
Word Equation & Conditions: الرقم الهيدروجيني = -لوغاريتم تركيز أيون الهيدروجين | pH + pOH = 14
Location & Specifications: الاتزان الأيوني، كيمياء 3 ثانوي، التحصيلي، و AP Chemistry.
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Lesson summary

Ecosystem organization EST Biology revision notes.Two species cannot share exactly the same niche for long (competitive exclusion).Biomestundra, desert, rainforest, grassland, taiga, deciduous forest.OrganismPopulationCommunityEcosystemBiomeBiosphereFactorsBiotic: predators, comp…

  • Ecosystem organization EST Biology: what to do next
  • Identify / Describe (FRQ)
  • Explain / Justify (FRQ)
  • MCQ technique
  • Keywords the mark scheme looks for in this lesson
  • How to get full marks (examiner guidance)

Part 1 of 6Key ideas

Two species cannot share exactly the same niche for long (competitive exclusion).
Biomes
Biomes tundra, desert, rainforest, grassland, taiga, deciduous forest.

Part 2 of 6Process & sequence

  • Organism
  • Population
  • Community
  • Ecosystem
  • Biome
  • Biosphere
Factors
Biotic predators, competitors, food
Abiotic temperature, water, light, soil

Part 3 of 6Summary

Summary
Community + abiotic factors = ecosystem.
An organism’s role is its niche.

Part 4 of 6Part 1

Ecosystem organization

Core summary Ecology explains how living organisms are organised and how they interact with one another and with non-living factors. The levels of organisation increase from an organism to a population, community, ecosystem, biome and finally the biosphere.

Part 1
Organism
Organism one individual living thing.
Population
Population members of one species living in the same area.
Community
Community all populations living and interacting in an area.
Ecosystem
Ecosystem a community plus abiotic factors such as light, temperature, water and soil.
Biome and biosphere
Biome and biosphere large groups of ecosystems and all ecosystems on Earth.

Exam focus when identifying an ecosystem, include both biotic communities and abiotic conditions. An organism’s niche describes its role and interactions in the ecosystem.

Part 5 of 6Keep going

Ecosystem organization EST Biology: what to do next

These Ecosystem organization EST Biology notes covered the key ideas, worked examples and exam technique for this topic. Check your Ecosystem organization EST Biology understanding with the practice questions below, then reread any Ecosystem organization EST Biology point you were unsure about before moving on.

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Practice: Ecosystem organization EST Biology practice questions
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Previous lesson: 1.10 EST II Biology — Cell Structure and Molecular Biology: Image Practice
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Next lesson: 2.2 Energy flow
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Course: EST 2 Biology — all units
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Official syllabus: OpenStax free science textbooks

Ecosystem organization EST Biology revision notes

Part 6 of 6Compare: Compare

Levels of ecological organisation
LevelIncludesExampleLiving only?ScaleStudy focus
OrganismOne individualOne lionYesSmallestAdaptations
PopulationOne speciesLions in SerengetiYes—Growth, density
CommunityAll speciesLions, zebras, grassYes—Interactions
EcosystemCommunity + abioticSerengeti plainsNo—Energy, cycles
BiomeSimilar ecosystemsSavannaNo—Climate
BiosphereAll life on EarthEarthNoLargestGlobal change

Key terms

Command terms

Command terms
Identify / Describe (FRQ)
A short, specific statement; describing requires relevant characteristics, not a single word.
Explain / Justify (FRQ)
Give the cause-and-effect reasoning or evidence; a restated fact does not score.
Calculate
Show setup, substitution and the answer with units.
Predict
State the expected outcome; add a reason only if asked to justify.
MCQ technique
Read every option; eliminate distractors that are true statements but do not answer the question; watch for NOT/EXCEPT.

Exam technique

Keywords the mark scheme looks for in this lesson

Keywords the mark scheme looks for in this lesson
Organism · Population · Community · Ecosystem · Biome · Biosphere · Habitat · Niche
Learn each definition in the Key words tab exactly; a missing keyword in a definition usually loses the mark.

How to get full marks (examiner guidance)

1
Answer exactly what is asked; extra correct material does not earn credit, and contradictory statements can cancel credit (AP FRQ).
2
Use precise vocabulary (e.g. “active site”, “concentration gradient”, “allele”), never “it/stuff/things”.
3
Show units and working in calculations.
4
In MCQs, predict the answer before reading the options, then eliminate.

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