Reproduction in Organisms
You can now identify the main components, explain the mechanism step by step, interpret an observation and distinguish related ideas.
Big idea
One parent produces offspring without gamete fusion, usually preserving the parent's genotype. Meiosis and gamete fusion combine genetic material from two gametes.
Learning goals
- Asexual reproduction: One parent produces offspring without gamete fusion, usually preserving the parent's genotype.
- Sexual reproduction: Meiosis and gamete fusion combine genetic material from two gametes.
- Clones and mutation: Asexual offspring are clones in principle, but mutation can still create differences.
- Sources of variation: Crossing over, independent assortment and random fertilization generate varied allele combinations.
- Reproductive trade-offs: Asexual reproduction can be fast, while sexual reproduction usually creates more variation that may aid adaptation.
Core concepts
1. Asexual reproduction
One parent produces offspring without gamete fusion, usually preserving the parent's genotype.
Observation: Binary fission rapidly produces genetically similar bacterial cells.
2. Sexual reproduction
Meiosis and gamete fusion combine genetic material from two gametes.
Observation: Fertilization restores diploid chromosome number in a zygote.
3. Clones and mutation
Asexual offspring are clones in principle, but mutation can still create differences.
Observation: A new mutation distinguishes one member of a clonal lineage.