Reproduction
Aperçu
Every organism on Earth exists because its parents reproduced successfully. Some species clone themselves with remarkable speed, while others invest months in courtship, pregnancy and parental care. Understanding how new individuals are made - whether by splitting a cell in two or by fusing specialised sex cells - is central to biology and to many of the medical, agricultural and conservation questions you will meet later in the course.
In this lesson you will compare sexual and asexual reproduction, trace the journey from pollination to seed dispersal in flowering plants, and follow human fertilisation through pregnancy to birth. You will also explore how four hormones orchestrate the menstrual cycle - a topic that Edexcel tests regularly across both papers.
Objectifs
- Understand the differences between sexual and asexual reproduction
- Understand that fertilisation involves the fusion of a male and female gamete to produce a zygote that undergoes cell division and develops into an embryo
- Describe the structures of an insect-pollinated and a wind-pollinated flower and explain how each is adapted for pollination
- Understand that the growth of the pollen tube followed by fertilisation leads to seed and fruit formation
- Investigate the conditions needed for seed germination
- Understand how germinating seeds utilise food reserves until the seedling can carry out photosynthesis
- Understand that plants can reproduce asexually by natural methods (illustrated by runners) and by artificial methods (illustrated by cuttings)
- Understand how the structure of the male and female reproductive systems are adapted for their functions
- Understand the roles of oestrogen and progesterone in the menstrual cycle
- Understand the roles of FSH and LH in the menstrual cycle
- Describe the role of the placenta in the nutrition of the developing embryo
- Understand how the developing embryo is protected by amniotic fluid
- Understand the roles of oestrogen and testosterone in the development of secondary sexual characteristics
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Évaluation de la leçon
Félicitations, vous avez terminé la leçon sur Reproduction. 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.
- Which of the following is the correct definition of fertilisation? A) The transfer of pollen from anther to stigma B) The release of an egg from the ovary C) The fusion of a male gamete nucleus with a female gamete nucleus D) The implantation of an embryo in the uterus wall Answer: C
- In the menstrual cycle, which hormone triggers ovulation? A) FSH B) Oestrogen C) Progesterone D) LH Answer: D
- Which of these is NOT a condition required for seed germination? A) Water B) Light C) Oxygen D) Warmth Answer: B
- What is the role of the stigma in a flower? A) To produce pollen grains B) To protect the flower bud C) To receive pollen grains during pollination D) To attract insects with nectar Answer: C
- How many chromosomes does a human zygote contain? A) 23 B) 44 C) 46 D) 92 Answer: C
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Livres recommandés
Pour aller plus loin, ressources libres
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Section de manuel
Pollination and Fertilization
Describe what must occur for plant fertilization
"Biology: Pollination and Fertilization" 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/32-2-pollination-and-fertilization. Access for free at https://openstax.org/books/biology/pages/1-introduction
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Section de manuel
Hormonal Control of Human Reproduction
Describe the roles of male and female reproductive hormones
"Biology: Hormonal Control of Human Reproduction" 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/43-4-hormonal-control-of-human-reproduction. 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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