Selective breeding: repeat selection, retain the risks
הוצג| English | משמעות |
|---|---|
| selective breeding/sɪˈlektɪv ˈbriːdɪŋ/ | בחירה מלאכותית |
| inbreeding/ˈɪnbriːdɪŋ/ | אינסואל |
What would explain this observation?
- Choosing a high-yielding parent is only the first step. Selective breeding 选择育种 needs offspring selection across generations and attention to unintended effects.
Build the model
- Selective breeding, or artificial selection, means humans breeding plants and animals for chosen inherited characteristics.
- Select parents with the desired feature from a mixed population, breed them, select offspring showing the feature and breed those.
- Repeat over many generations.
- Examples include disease resistance in food crops, greater meat or milk production, a gentle nature in dogs and large or unusual flowers.
- selective breeding: Human selection of parents and offspring for desired inherited features.
- inbreeding 近交: Breeding closely related individuals, which can increase inherited-defect risks.
Which step must follow breeding the selected parents?
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
Selective breeding is iterative: from the offspring, choose the ones showing the desired trait, breed them, and repeat over many generations. Nothing is inserted into cells, and no trait is fixed in one step.
Match each technical term to its precise meaning.
רמת קושי 2/5 · 140 מטבעות + בונוס קטן בהשלמה הראשונה היום
Use the definitions to distinguish related quantities and processes.
Choose evidence that can test it
- Useful and attractive characteristics are not necessarily the same.
- Repeatedly breeding closely related individuals can cause inbreeding, making some breeds more prone to disease or inherited defects.
- A narrow breeding population may reduce variation.
- Evaluate production benefits alongside health, welfare and resilience rather than treating one selected measurement as the whole organism’s value.
In the lab: Analyse supplied breeding records with yield, disease and parentage stated. Identify the chosen criterion, describe the repeated selection sequence and compare any health costs. A classroom task can use fictional pedigrees and plant data; animal breeding or welfare interventions are not student experiments.
Which two habits make the investigation or model in this case more defensible?
רמת קושי 2/5 · 140 מטבעות + בונוס קטן בהשלמה הראשונה היום
Stating the conditions and assumptions lets others repeat the work exactly, and recording the supporting evidence lets them check the conclusion. Hiding disagreeing results removes the evidence that could challenge a wrong conclusion, and one measurement can never establish a wider claim.
Work from known quantities
- Known: a fictional crop’s mean yield rises from 2.4 to 3.0 kg per plant after the stated selection programme.
- Increase = 0.6 kg; percentage increase = 0.6/2.4×100 = 25%.
- Without matched conditions or a comparison line, this observation alone cannot attribute all the increase to inherited selection.
Your turn: A supplied yield rises from 4.0 to 5.0 kg per plant. Calculate percentage increase.
A supplied yield rises from 4.0 to 5.0 kg per plant. Calculate percentage increase.
רמת קושי 2/5 · 140 מטבעות + בונוס קטן בהשלמה הראשונה היום
The result is 25 %. Known: yield rises from 4.0 to 5.0 kg per plant. Increase = 1.0 kg. Percentage increase = 1.0/4.0 x 100 = 25%. Attributing it to selection needs a matched comparison.
Check the conclusion and its limits
- Selective breeding does not insert a chosen gene directly into a cell.
- It uses reproduction and selection over generations.
- Choosing every parent from one family can intensify inherited risks; a greater average yield is not proof that all other traits improved.
Not true: Selective breeding and inserting a gene with a vector are the same process. Selective breeding chooses parents and lets reproduction shuffle existing alleles over generations. Genetic engineering inserts a chosen gene directly - different mechanisms entirely.
- Selective breeding, or artificial selection, means humans breeding plants and animals for chosen inherited characteristics.
- Useful and attractive characteristics are not necessarily the same.
- Watch for: selective breeding does not insert a chosen gene directly into a cell.
Selective breeding and inserting a gene with a vector are the same process.
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
Selective breeding chooses parents and lets reproduction shuffle existing alleles over generations. Genetic engineering inserts a chosen gene directly - different mechanisms entirely.
Human selection of parents and offspring for desired inherited features: write the technical term.
רמת קושי 1/5 · 100 מטבעות + בונוס קטן בהשלמה הראשונה היום
selective breeding means Human selection of parents and offspring for desired inherited features.