Unit 2-Variation And Sexual Reproduction Flashcards
Give three disadvantages of sexual reproduction
High metabolic cost, gametes are made by special type of cell division
Reproduction rate is much slower
Only half of the population can actually produce offspring
Give two disadvantages of needing males for sexual reproduction
- Males are unable to produce the offspring, so only half the population can reproduce
- Only half of each parent’s genome is passed on so disrupts successful parental genomes
Name a mechanism used by bacteria to allow the exchange of genetic material between generations
Horizontal Gene Transfer (HGT)
Give examples of vegetative cloning methods in plants
Bulbs - Daffodils
Tubers - Potato
Rhizomes - Ginger
Spores - Fungi
What is parthenogenesis?
Production of haploid offspring without needing males or fetilization
Give conditions that parthenogenesis is common
Cooler Climates
Lower level of Parasitism
In what conditions is asexual reproduction beneficial?
Very narrow and stable niche
Recolonising disrupted habitats
Give an example of an area where asexual reproduction is beneficial
Butter cups using stolons to spread into flower beds with clear soil, gaining a competitive advantage
What is the diploid number of chromosomes for humans?
46
Give characteristics that are the same in homologous chromosomes
Same size
Same centromere position
Same genes at the same loci
What is the first stage in meiosis?
Long uncoiled chromosomes replicate to form two identical chromatids
Chromosomes coil up and become visibile
What is the site called where homologous chromosomes cross called?
Chiasma (plr. Chiasmata)
What are seperated during Meiosis I?
Pairs of homologous chromosomes (Not actually any chromosomes, its the pairs)
What is Independent Assortment?
A way of producing variation between daughter cells due to the fact there is no control over which chromosomes of each pair goes to which side of the cell
How many different combinations of chromosomes is there in the resulting haploid cells where n is the number of homologous pairs?
2^n