Sexual Reproduction
When one haploid cell from each parent fuses together to create one single unique diploid cell(zygote) through sex.
The six advantages of sexual reproduction are?
- genetic diversity
- select beneficial mutations
- can survive in a variety of environmental settings
- reduces the risk of genetic diseases
- ability to adapt to environmental changes
- harmful mutations can be purged from future generations
Disadvantages of Sexual Reproduction
- more energy is utilized to find a mate
- fewer offspring are produced
- offspring doesn’t allows receive the best genes
Asexual Reproduction
When an organism makes more of itself without exchanging genetic material with another organism through sex
Four advantages of asexual reproduction
- positive genetic influences are guaranteed to be passed on to future generations
-minimal energy utilization - only one organism is needed to start a colony
- does not require specialized cells
Disadvantages of Asexual Reproduction
- harmful mutations linger longer
- limited genetic diversity
- competition between offspring
- one change can eliminate an entire species
Mitosis
A process of cell reproduction, duplication where two genetically identical daughter cells are produced
What happens in Prophase?
1st stage
- nucleolus disappears and the nuclear envelope disintegrates
- chromatins coils and condenses into visible chromosomes
- centrosomes move apart, microtubules extend and mitotic spindle forms
- centromeres are attached to microtubules
Metaphase
- 2nd stage
- sister chromatids are lined up in the linear plane in the middle of the cell
- metaphase plate forms between centrosomes
- microtubules pull apart sister chromatids
Anaphase
-3rd stage
- pairs of chromosomes are separated to form chromosomes once again
-the chromosomes are pulled to
opposite ends, the microtubules
shorten.
- The new daughter cells will contain
identical genetic material.
Telophase
final stage
- the formation of two new
daughter nuclei at either end of the dividing
cell.
- Chromosomes return to loosely packed
chromatin
- Nucleoli reappear within the new nuclear
membrane
- Mitotic spindle breaks apart
- Each cell receives its own complement of
DNA, organelles, membranes, and centrioles.
- The cell is now ready to split in half as
cytokinesis begins
Importance of Mitosis
-provides new cells for growth and for replacement of worn-out cells, such
as skin cells.
- primary means of asexual reproduction.
Meosis
- Meiosis takes place in specialized tissues (e.g. ovaries and
testes) - Involves two divisions and results in four daughter cells, each
containing only half the original number of chromosomes (23
in the case of humans)
Importance of Meiosis
- The production of sex cells (gametes)
- allows adaptations that
will help in surviving in an ever-changing environment. - repair and regulation of genetic abnormalities
that tend to arise in sex cells.
