Advantages And Disadvantages Of Mitosis




BIO372 : Biological & Ecological Implications of Sex : Benefits & Merchandise-offs : Lesson

Benefits & Trade-offs: Lesson

Use the outline below to guide your study of the material in this lesson. The outline indicates those topics the instructor feels are virtually important for you to learn in the course. Yous should read all the pages assigned, open up and study the links, and read the terms in the glossary.

I. Organisms tin can be composed of one cell or of many

Prison cell - the smallest unit of measurement of life
- Nucleus
  - Genes are located on (homologous) chromosomes
  - Chromatin: the genetic material of the chromosomes
  - Ploidy: haploid, diploid, polyploid (approximately 1/iii of flowering plants)
- Cytoplasm
  - Builds proteins
  - Jail cell cycle

Two. Asexual Reproduction

Mitosis ("my-toe'-sister")
- A single jail cell division
- Two girl cells receive exactly the same genetic fabric that the parent jail cell had
- Mitosis with animation
  - Blue chromosomes from the dad, red from the mom
  - Two strands in each chromosome, strands are exact copies of each other
  - 1 strand of each chromosome goes to ane daughter cell, the other strand to the 2nd girl cell

Advantages
- Speed: rapid production of offspring
- Fidelity to parents: well-adapted parents produce equally well-adapted offspring
- Available resources are speedily monopolized
- Population well adjusted to a narrow niche does well under special environmental atmospheric condition, eastward.g., polluted areas
Disadvantages
- Limited flexibility to meet a irresolute surround: a detail strain of cells is well-adjusted to a relatively narrow niche
- Low multifariousness: all cells are identical
- Efficient parasites wipe out an entire population (cf., the Red Queen Hypothesis)

Iii. Sexual Reproduction

Meiosis ("my-oh'-sis")
- Two prison cell divisions
- Produces four daughter cells chosen gametes
- Each gamete contains but half the chromsomes equally the parent cell
- Recombination (=crossing over): each gamete may comprise genetic material which is unlike from each other and from the parent cell
- In "college organisms" the fusion of two gametes produces a new private

Advantages
- Multifariousness of offspring: in a irresolute surroundings, there is a high probability that at least some offspring will be well adapted
- Novel combinations of genes potentially produce new adaptations (through recombination)
- Favorable mutations in unlike individuals can come together in a single offspring
- Offspring with harmful mutations die, resulting in removing the harmful mutations from the population
- New combinations of genes lead to exploitation of new niches: evolution
- Preadaptation: when the environs changes, the population already contains individuals which are adapted to the new conditions
  - Example: when colonists brought measles to the New World, some Native American individuals were resistant although about were not
  - Example: some few individuals resistant to HIV have been found
Disadvantages
- Boring: it takes two cell divisions
- Complicated: crossing over
- Higher probability of errors
- Genetic load: reassortment of genes tin can bring deleterious alleles from different parents together in a single offspring
- Price of sexual activity: need to produce males, but this is not a disadvantage if the male contributes to the survival and success of the offsping
- Cost of recombination: breaks up favorable combinations of genes, both on the same chromosome and in the same individual