Form 5 BiologyBiologi Tingkatan 5

Chapter 9: EcosystemBab 9: Ekosistem

Understand how organisms interact with their environment, how energy flows through food webs, and how nutrients cycle through ecosystems!Fahami bagaimana organisma berinteraksi dengan persekitaran, bagaimana tenaga mengalir melalui rantaian makanan, dan bagaimana nutrien dikitar semula dalam ekosistem!

🎯 What You'll LearnApa Yang Anda Akan Pelajari

Define ecosystem components — biotic and abiotic factorsMentakrifkan komponen ekosistem — faktor biotik dan abiotik

Describe population, community, ecosystem, habitat, and nicheMenerangkan populasi, komuniti, ekosistem, habitat dan nis

Construct food chains and food webs, and explain energy flowMembina rantaian makanan dan r rangkaian makanan, serta menerangkan aliran tenaga

Explain the carbon and nitrogen cyclesMenerangkan kitar karbon dan kitar nitrogen

Identify symbiotic relationships — mutualism, commensalism, parasitismMengenal pasti hubungan simbiosis — mutualisme, komensalisme, parasitisme

🔥 Ecosystem ComponentsKomponen Ekosistem

🔎 KEY CONCEPT:KONSEP UTAMA: An ecosystem is a community of living organisms (biotic factors) interacting with their non-living environment (abiotic factors). Energy flows through one direction, while nutrients cycle continuously.Ekosistem ialah komuniti organisma hidup (faktor biotik) yang berinteraksi dengan persekitaran bukan hidup (faktor abiotik). Tenaga mengalir satu arah, manakala nutrien dikitar semula secara berterusan.

Ecological TermsIstilah Ekologi

TermIstilahDefinitionDefinisiExampleContoh
Species
(Spesies)Spesies		Group of organisms that can interbreed and produce fertile offspringKumpulan organisma yang boleh membiak dan menghasilkan zuriat suburHumans, tigersManusia, harimau
Population
(Populasi)Populasi		Group of the same species in a defined areaKumpulan spesies yang sama dalam kawasan tertentuAll buffaloes in a fieldSemua kerbau di suatu padang
Community
(Komuniti)Komuniti		All populations of different species in an areaSemua populasi spesies berbeza dalam suatu kawasanFish, crabs, seaweed in a pondIkan, ketam, rumput laut di kolam
Ecosystem
(Ekosistem)Ekosistem		Community + abiotic environmentKomuniti + persekitaran abiotikA mangrove ecosystemEkosistem bakau
Habitat
(Habitat)Habitat		The physical place where an organism livesTempat fizikal di mana organisma hidupMangrove mud for crabsLumpur bakau untuk ketam
Niche
(Nis)Nis		The role and position of an organism in the ecosystemPeranan dan kedudukan organisma dalam ekosistemFrog = insect eater + tadpole as primary consumerKatak = pemakan serangga + berudu sebagai pengguna primer

Biotic and Abiotic FactorsFaktor Biotik dan Abiotik

Biotic (Living)Biotik (Hidup)Abiotic (Non-living)Abiotik (Bukan Hidup)
Producers (plants, phytoplankton)Pengeluar (tumbuhan, fitoplankton)Light intensityKeamatan cahaya
Primary consumers (herbivores)Pengguna primer (herbivor)TemperatureSuhu
Secondary consumers (carnivores)Pengguna sekunder (karnivor)HumidityKelembapan
Tertiary consumersPengguna tertierpH, salinity, topographypH, kemasinan, topografi
Decomposers (bacteria, fungi)Pengurai (bakteria, kulat)Water availability, oxygenKetersediaan air, oksigen

📤 Energy FlowAliran Tenaga

Energy flows through ecosystems in a one-directional path from the sun through trophic levels.Tenaga mengalir melalui ekosistem dalam laluan satu arah dari matahari melalui aras trofik.

Food Chain & Food WebRantaian Makanan & Rangkaian Makanan

FeatureCiriFood ChainRantaian MakananFood WebRangkaian Makanan
DefinitionDefinisiA linear pathway of energy transferLaluan linear pemindahan tenagaInterconnected food chainsRantaian makanan yang saling berkait
ComplexityKerumitanSimple, single pathwayRingkas, laluan tunggalComplex, multiple pathwaysRumit, laluan berbilang
ExampleContohGrass → Grasshopper → Frog → Snake → EagleRumput → Belalang → Katak → Ular → HelangAll interconnected relationships in an ecosystemSemua hubungan saling berkait dalam ekosistem
💡 The 10% Rule:Aturan 10%: Only about 10% of energy is transferred from one trophic level to the next. The remaining 90% is lost as heat (respiration), movement, undigested food, and waste. This is why food chains rarely exceed 4-5 trophic levels.Hanya kira-kira 10% tenaga dipindahkan dari satu aras trofik ke aras seterusnya. Bakinya 90% hilang sebagai haba (respirasi), pergerakan, makanan tidak dihadam, dan sisa. Inilah sebabnya rantaian makanan jarang melebihi 4-5 aras trofik.

Ecological PyramidsPiramid Ekologi

TypeJenisWhat It ShowsApa Yang DitunjukkanShapeBentuk
Pyramid of Numbers
(Bilangan)Piramid Bilangan		Number of organisms at each levelBilangan organisma pada setiap arasMay be inverted (one tree → many insects)Mungkin terbalik (satu pokok → banyak serangga)
Pyramid of Biomass
(Biojisim)Piramid Biojisim		Total dry mass at each levelJumlah jisim kering pada setiap arasAlways uprightSentiasa tegak
Pyramid of Energy
(Tenaga)Piramid Tenaga		Energy content at each levelKandungan tenaga pada setiap arasAlways upright (energy always decreases)Sentiasa tegak (tenaga sentiasa berkurang)

📡 Nutrient CyclingKitaran Nutrien

Carbon CycleKitar Karbon

Carbon moves between the atmosphere, living organisms, and the Earth.Karbon bergerak antara atmosfera, organisma hidup, dan bumi.

🔎 Key processes:Proses utama:
• Photosynthesis: CO₂ from atmosphere → incorporated into glucose by plantsFotosintesis: CO₂ dari atmosfera → dijadikan glukosa oleh tumbuhan
• Respiration: Glucose broken down → CO₂ released back to atmosphereRespirasi: Glukosa diuraikan → CO₂ dilepaskan ke atmosfera
• Combustion: Burning fossil fuels releases stored carbon as CO₂Pembakaran: Pembakaran bahan api fosil melepaskan karbon tersimpan sebagai CO₂
• Decomposition: Decomposers break down dead organisms, releasing CO₂Penguraian: Pengurai menguraikan organisma mati, melepaskan CO₂

Nitrogen CycleKitar Nitrogen

ProcessProsesDescriptionKeteranganBacteria InvolvedBakteria Terlibat
Nitrogen Fixation
(Pengikatan nitrogen)Pengikatan nitrogen		N₂ from atmosphere → ammonia (NH₃)N₂ dari atmosfera → ammonia (NH₃)Rhizobium (root nodules of legumes)Rhizobium (nodul akar legum)
Nitrification
(Nitrifikasi)Nitrifikasi		Ammonia → nitrite → nitrate (NO₃⁻)Ammonia → nitrit → nitrat (NO₃⁻)Nitrosomonas, NitrobacterNitrosomonas, Nitrobacter
Assimilation
(Asimilasi)Asimilasi		Plants absorb nitrate to make proteinsTumbuhan menyerap nitrat untuk membuat proteinPlants absorb through root hair cellsTumbuhan menyerap melalui sel rambut akar
Ammonification
(Ammonifikasi)Ammonifikasi		Dead organisms → ammonia by decomposersOrganisma mati → ammonia oleh penguraiAmmonifying bacteriaBakteria pengamoniaan
Denitrification
(Denitrifikasi)Denitrifikasi		Nitrate → N₂ gas (returns to atmosphere)Nitrat → gas N₂ (kembali ke atmosfera)Pseudomonas (in waterlogged soils)Pseudomonas (dalam tanah tepu air)
Food Chain & Ecological Pyramids Producer → 1st Consumer → 2nd Consumer → 3rd Consumer → Decomposer Pyramid of Numbers Producers (many) 1st Consumer 2nd 3rd SPM: Energy decreases at each trophic level (10% rule)

🤝 Symbiotic RelationshipsHubungan Simbiosis

RelationshipHubunganABExampleContoh
Mutualism
(Mutualisme)Mutualisme		✅✅Clownfish & sea anemone; Rhizobium & legume rootsIkan badut & anemon laut; Rhizobium & akar legum
Commensalism
(Komensalisme)Komensalisme		✅⚠️Bird's nest fern & tree; remora & sharkPaku sarang burung & pokok; ikan remora & ikan jerung
Parasitism
(Parasitisme)Parasitisme		✅❌Tick on dog; tapeworm in human intestineKutu pada anjing; cacing pita dalam usus manusia
Predation
(Pemangsaaan)Pemangsaaan		✅❌Tiger hunting deerHarimau memburu rusa
Competition
(Persaingan)Persaingan		❌❌Two plants competing for lightDua tumbuhan bersaing untuk cahaya

💯 Quick CheckSemakan Pantas

Why are there rarely more than 4-5 trophic levels in a food chain?Mengapa jarang ada lebih daripada 4-5 aras trofik dalam rantaian makanan?

APredators kill too many preyPemangsa membunuh terlalu banyak mangsa
BDecomposers consume all the energyPengurai menggunakan semua tenaga
COnly 10% of energy is transferred, so not enough energy remains at higher levelsHanya 10% tenaga dipindahkan, jadi tidak cukup tenaga pada aras lebih tinggi
DProducers cannot produce enough foodPengeluar tidak boleh menghasilkan makanan yang cukup

🇲🇾 Malaysian EcosystemsEkosistem Malaysia

🌃 Mangrove forests — Found along Malaysian coasts (Sungai Merbok, Matang Mangrove). Complex food webs involving phytoplankton → shrimp → fish → herons. Rhizophora provides habitat and nursery grounds.Hutan bakau — Dijumpai di pantai Malaysia (Sungai Merbok, Bakau Matang). Rangkaian makanan kompleks melibatkan fitoplankton → udang → ikan → burung heron. Rhizophora menyediakan habitat dan tempat membiak.

🐝 Coral reefs of Sipadan — Part of the Coral Triangle (world's highest marine biodiversity). Diverse food webs with coral polyps, clownfish, sea turtles, reef sharks.Terumbu karang Sipadan — Sebahagian daripada Segi Tiga Karang (biodiversiti marin tertinggi dunia). Rangkaian makanan pelbagai dengan polip karang, ikan badut, penyu laut, jerung karang.

🌄 Tropical rainforest — Multi-layered ecosystem (emergent, canopy, understory, forest floor) with intricate producer-consumer-decomposer relationships.Hutan hujan tropika — Ekosistem berlapis (lapisan muncul, kanopi, bawah kanopi, lantai hutan) dengan hubungan pengeluar-pengguna-pengurai yang rumit.

📋 SPM PracticeLatihan SPM

SPM 2020 Paper 2SPM 2020 Kertas 2

The diagram below shows a food chain in a paddy field: Paddy plant → Rat → Snake → EagleRajah di bawah menunjukkan rantaian makanan di sawah padi: Pokok padi → Tikus → Ular → Helang

(a) State the trophic level occupied by the snake. [1 mark](a) Nyatakan aras trofik yang diwakili oleh ular. [1 markah]

(b) If the snake population decreases, explain the effect on the paddy yield. [2 marks](b) Jika populasi ular berkurang, jelaskan kesan terhadap hasil padi. [2 markah]

(c) Name the process by which nitrogen is converted into nitrates in the soil and state the bacteria involved. [3 marks](c) Namakan proses di mana nitrogen ditukar kepada nitrat dalam tanah dan nyatakan bakteria yang terlibat. [3 markah]

📌 Exam Tip:Tip Peperiksaan: (a) Secondary consumer / 3rd trophic level. (b) Rat population increases → more paddy eaten → yield decreases. (c) Nitrification, carried out by Nitrosomonas (ammonia → nitrite) and Nitrobacter (nitrite → nitrate).(a) Pengguna sekunder / aras trofik ke-3. (b) Populasi tikus meningkat → lebih banyak padi dimakan → hasil berkurang. (c) Nitrifikasi, dilakukan oleh Nitrosomonas (ammonia → nitrit) dan Nitrobacter (nitrit → nitrat).

🃏 FlashcardsKad Imbas

What is a niche?Apakah nis?
The role/function of an organism in its ecosystem (not just where it lives)Peranan/fungsi organisma dalam ekosistemnya (bukan hanya di mana ia hidup)
10% RuleAturan 10%
Only 10% of energy transfers to next trophic level; 90% lost as heatHanya 10% tenaga berpindah ke aras trofik seterusnya; 90% hilang sebagai haba
Nitrogen FixationPengikatan Nitrogen
N₂ → NH₃ by Rhizobium (in legume root nodules) or lightningN₂ → NH₃ oleh Rhizobium (dalam nodul akar legum) atau kilat
Mutualism (+, +)Mutualisme (+, +)
Both organisms benefit (e.g., clownfish & sea anemone)Kedua-dua organisma mendapat manfaat (contoh: ikan badut & anemon laut)
Carbon is returned to atmosphere by...Karbon dikembalikan ke atmosfera melalui...
Respiration, combustion, decompositionRespirasi, pembakaran, penguraian