B5.1 Inheritance Flashcards
What is variation?
Differences within species.
State four examples of variation.
- Height
- Build
- Eye colour
- Hair colour
- Blood group
- Language
Name the two causes of variation within species.
- Genetics
- Environment.
How can variation of a characteristic displayed be further categorised?
Into continuos vs. discontinuous variation.
What is discontinuous variation?
- Variation that produces distint categories
- e.g. Eye colour, blood group, gender
What is continuous variation?
- Variation that cannot be placed in distinct categories and instead produces a spectrum
- e.g. height, weight, skin colour
What type of variation will human body mass display?
Continuous.
What causes variation?
Mutations in the genetic code.
What is asexual reproduction?
- Reproduction that produces a clone that is a genetically identical to it single parent.
- There is no mixing of genetic material
Give two examples of organisms that can replicate asexually.
- Potato plants
- Stawberries
- Spider plants
- Bacteria
- Mushrooms
- Daffodils
How does asexual reproduction take place?
Mitosis.
What is sexual reproduction?
- Reproduction requiring two parents
- Genetic information is taken from both parents
- Organisms produce haploid gametes that fuse during fertilisation
- Offspring are not identical
- Results in variation
Give one advantage and one disadvantage of sexual reproduction.
- Advantage: Variation in offspring leads to adaptation in a species. This results in some organisms within a species containing adaptations that allow them to cope with an environmental pressue. These organisms can reproduce, enabling the species/population to survive.
- Disadvantage: Reproduction requires two parents. Reproduction is slowers, so few offspring are produced.
Give one advantage and one disadvantage of asexual reproduction.
Advantages
- If the parent was well adapted to an area then the offspring will share an identical set of characteristics
- Only one parent is needs - animals do not need to find a partner, plants do not require pollination.
- Faster, so large numbers of offspring are produced quickly
Disadvantage:
- Adverse changes to the biotic or abiotic factors may destroy the species, as all organisms affected due to the being no variation.
What is a gamete?
- A sex cell
- Haploid cell used in sexual reproduction
- Sperm & egg
- Pollen & ovule
What is a chromosome?
Tightly packaged DNA wrapped around histone proteins.
What is a gene?
A section of DNA that can (but not always) code for a protein.