--- marp: true theme: default html: true --- # Quick check: reproductive organs and strategies Year 9 Biology · Reproduction --- ## Today **We are learning to** a few quick questions on reproductive structures, asexual reproduction, and comparing the two strategies. Taught in class; use this to check yourself. - I can name reproductive structures and what they do. - I can describe two kinds of asexual reproduction. - I can compare sexual and asexual reproduction and say when each helps. --- ## Why it matters > A strawberry plant sends out runners; a bacterium splits in two. When is cloning a good strategy, and when is it risky? --- ✅ Check ## What does each do? **What is the main job of this structure?** Groups: Makes gametes · Transfers or receives gametes · Where the embryo develops Testis · Ovary · Anther (in a flower) · Sperm duct · Stigma · Uterus * Answer: Testis → Makes gametes; Ovary → Makes gametes; Anther (in a flower) → Makes gametes; Sperm duct → Transfers or receives gametes; Stigma → Transfers or receives gametes; Uterus → Where the embryo develops --- ✅ Check ## Pollination **What is pollination?** - The growing of a seed into a plant - The joining of a male and a female gamete - The release of eggs from an ovary - The transfer of pollen from an anther to a stigma * Answer: The transfer of pollen from an anther to a stigma --- ✅ Check ## Working together **How do the male and female reproductive structures work together?** - The male structures make the embryo and the female structures only feed it - Either set can make offspring on its own; the other is a backup - The gametes join inside the testis or the anther - Each makes gametes, and the structures carry them to meet so fertilisation can happen * Answer: Each makes gametes, and the structures carry them to meet so fertilisation can happen --- ✅ Check ## Stamen and carpel **Match each flower part to its job.** | | | |---|---| | `Stamen (anther and filament)` | A. Receives pollen and holds the ovules, where fertilisation happens | | `Carpel (stigma, style and ovary)` | B. Attract pollinators | | `Petals` | C. Makes and holds pollen, which carries the male gametes | * Answer: Stamen (anther and filament) → C. Makes and holds pollen, which carries the male gametes; Carpel (stigma, style and ovary) → A. Receives pollen and holds the ovules, where fertilisation happens; Petals → B. Attract pollinators --- ✅ Check ## Asexual or sexual? **Is it asexual or sexual reproduction?** Groups: Asexual · Sexual A strawberry plant growing new plants on runners · A hydra growing a bud that breaks away · A bacterium splitting in two · A flower pollinated and making seeds · An egg fertilised by a sperm * Answer: A strawberry plant growing new plants on runners → Asexual; A hydra growing a bud that breaks away → Asexual; A bacterium splitting in two → Asexual; A flower pollinated and making seeds → Sexual; An egg fertilised by a sperm → Sexual --- ✅ Check ## When it helps **When is asexual reproduction an advantage?** - When the species needs variety - When the environment changes suddenly - In a stable environment or when spreading quickly, because one parent can make many offspring fast - Never * Answer: In a stable environment or when spreading quickly, because one parent can make many offspring fast --- ✅ Check ## The limit **What is the main limit of asexual reproduction?** - Offspring are genetically identical, so one disease or change can harm them all - It can only happen in plants - It is too slow - It needs two parents * Answer: Offspring are genetically identical, so one disease or change can harm them all --- ✅ Check ## Sexual or asexual? **Which strategy does this describe?** Groups: Sexual · Asexual Offspring differ from each other and their parents · Offspring are clones of the parent · Many offspring can be made quickly by one parent · Needs gametes from two parents · Gives some chance of survival if the environment changes · Needs energy and time to find a mate and make gametes · Needs only one parent, so less energy is spent per offspring * Answer: Offspring differ from each other and their parents → Sexual; Offspring are clones of the parent → Asexual; Many offspring can be made quickly by one parent → Asexual; Needs gametes from two parents → Sexual; Gives some chance of survival if the environment changes → Sexual; Needs energy and time to find a mate and make gametes → Sexual; Needs only one parent, so less energy is spent per offspring → Asexual --- ✅ Check ## A new disease **A new disease spreads through a population. Which population is more likely to have survivors?** - One that reproduces sexually, because its variation may include resistant individuals - One that reproduces asexually, because the clones are identical - Neither can have survivors - Both are equally likely * Answer: One that reproduces sexually, because its variation may include resistant individuals --- ✅ Check ## Using both **Aphids reproduce asexually in summer and sexually in autumn. Why might it help to use both?** - Asexual is fast when conditions are good; sexual makes variation for harder times - Sexual is faster in summer - Asexual makes more variation - It makes no difference * Answer: Asexual is fast when conditions are good; sexual makes variation for harder times --- ✅ Check ## Exit ticket **Give one advantage and one disadvantage of asexual reproduction.** * Advantage: fast with one parent. Disadvantage: no variation, so one change or disease can harm all.