Ecosystems
Aperçu
A rock pool, a patch of rainforest and the open ocean look nothing alike, yet each is an ecosystem: a community of living things and the non-living surroundings they depend on, all linked by the steady flow of energy and the endless recycling of matter. Pull on one thread, such as removing a top predator or a single insect, and the whole web can shift in ways no one predicted. Understanding how an ecosystem fits together is the first step to managing it without breaking it.
In this lesson you will meet the building blocks of an ecosystem, from habitat and niche to producers, consumers and decomposers, and the biotic and abiotic factors that shape life. You will trace energy through food chains, food webs and trophic levels, learn why only about a tenth of it passes between levels, and follow carbon as it cycles through photosynthesis, respiration, feeding, decomposition and combustion.
Objectifs
- 5.1.1 Describe the components of an ecosystem, limited to: (a) habitat (b) species (c) population (d) community (e) niche (f) prey (g) predator (h) apex predator.
- 5.1.2 Describe the biotic and abiotic components of an ecosystem, limited to: (a) biotic (living): producers, primary, secondary and tertiary consumers and decomposers (b) abiotic (non-living): temperature, water, oxygen, carbon dioxide, salinity, light, pH.
- 5.1.3 Describe biotic interactions, limited to: (a) native and invasive species (b) competition (c) predation (d) pollination.
- 5.1.4 Describe pollination, limited to: (a) the transfer of pollen from an anther to a stigma (b) insect pollination by an insect pollinator (c) wind pollination (d) pollination leads to fertilisation followed by seed and fruit formation. Knowledge of the structure and naming of flower parts are not required.
- 5.1.5 Describe the process of photosynthesis and the importance of chlorophyll, limited to: (a) synthesis of glucose using carbon dioxide and water (b) sunlight as the source of energy (c) chlorophyll to capture light energy (d) word equation: carbon dioxide + water → glucose + oxygen.
- 5.1.6 Describe and interpret energy flow using food chains, food webs and trophic levels, limited to: (a) 10% of energy is passed between trophic levels (producer, primary consumer, secondary consumer and tertiary consumer) (b) energy lost during life processes: movement, respiration, digestion and excretion.
- 5.1.7 Describe, interpret and explain ecological pyramids based on numbers and energy.
- 5.1.8 Describe the process of aerobic respiration, limited to: (a) break down of glucose in the presence of oxygen to release energy, with carbon dioxide and water as waste products (b) word equation: glucose + oxygen → carbon dioxide + water.
- 5.1.9 Describe the carbon cycle, limited to: (a) photosynthesis (b) respiration (c) feeding (d) decomposition (e) formation of fossil fuels (f) combustion.
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Évaluation de la leçon
Félicitations, vous avez terminé la leçon sur Ecosystems. Maintenant que vous avez exploré le concepts et idées clés, il est temps de mettre vos connaissances à lépreuve. Cette section propose une variété de pratiques des questions conçues pour renforcer votre compréhension et vous aider à évaluer votre compréhension de la matière.
Vous rencontrerez un mélange de types de questions, y compris des questions à choix multiple, des questions à réponse courte et des questions de rédaction. Chaque question est soigneusement conçue pour évaluer différents aspects de vos connaissances et de vos compétences en pensée critique.
Utilisez cette section d'évaluation comme une occasion de renforcer votre compréhension du sujet et d'identifier les domaines où vous pourriez avoir besoin d'étudier davantage. Ne soyez pas découragé par les défis que vous rencontrez ; considérez-les plutôt comme des opportunités de croissance et d'amélioration.
- All the individuals of one species living in an area are called a: A. community B. population C. habitat D. niche Answer: B
- Which of these is an abiotic component of an ecosystem? A. a decomposer B. a producer C. salinity D. a herbivore Answer: C
- Approximately what percentage of energy passes from one trophic level to the next? A. 1% B. 10% C. 50% D. 90% Answer: B
- In a food chain the arrows show the direction of: A. energy flow B. water movement C. predator escape D. decay Answer: A
- Which process removes carbon dioxide from the atmosphere? A. respiration B. combustion C. photosynthesis D. decomposition Answer: C
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Livres recommandés
Pour aller plus loin, ressources libres
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Section de manuel
Energy Flow through Ecosystems
Describe how organisms acquire energy in a food web and in associated food chains
"Biology: Energy Flow through Ecosystems" by OpenStax, OpenStax, Rice University, licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Source: https://openstax.org/books/biology/pages/46-2-energy-flow-through-ecosystems. Access for free at https://openstax.org/books/biology/pages/1-introduction
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Section de manuel
The Scope of Ecology
Define ecology and the four levels of ecological research
"Biology: The Scope of Ecology" by OpenStax, OpenStax, Rice University, licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Source: https://openstax.org/books/biology/pages/44-1-the-scope-of-ecology. Access for free at https://openstax.org/books/biology/pages/1-introduction
Publiées par d'autres organisations sous licence libre, créditées comme elles le demandent. Les liens ouvrent leurs sites.
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