meiosis

Pros of Sexual Reproduction

Increased genetic diversity, ability to adapt to changing environments, and potential for evolution.

Cons of Sexual Reproduction

Requires a mate, increased time and energy to find a partner, and risk of sexually transmitted diseases.

Pros of Asexual Reproduction

Quick reproduction, no need for a mate, and produces genetically identical offspring.

Cons of Asexual Reproduction

Lack of genetic diversity, vulnerability to environmental changes, and potential for overpopulation.

Which type of reproduction is better?

It depends on environmental conditions; sexual reproduction is better in fluctuating environments, while asexual reproduction is efficient in stable environments.

Diploid Cells

Cells that have two sets of chromosomes (one from each parent); in humans, diploid cells have 46 chromosomes.

Haploid Cells

Cells that have one set of chromosomes; in humans, haploid cells have 23 chromosomes and occur in gametes (sperm and egg).

Somatic Cells

Body cells that are diploid, containing two copies of each chromosome; involved in growth and repair.

Germ Cells

Reproductive cells that are haploid; give rise to gametes through meiosis.

Reason for Meiosis

To reduce the chromosome number by half to produce haploid gametes, and to increase genetic variation through recombination.

Homologous Chromosomes

Pairs of chromosomes, one from each parent, that have the same genes but may contain different alleles.

Sister Chromatids

Identical copies of a chromosome formed by DNA replication, joined at the centromere.

Similarities between Spermatogenesis and Oogenesis

Both are processes of gamete formation and involve meiosis, producing haploid cells.

Differences between Spermatogenesis and Oogenesis

Spermatogenesis produces four viable sperm cells, while oogenesis typically results in one viable egg and polar bodies; oogenesis has a longer duration.

Forms of Genetic Variation

Include crossing over, independent assortment, and random fertilization; occur during meiosis and increase genetic diversity.

Meiosis Steps

Meiosis consists of two rounds of division (Meiosis I and Meiosis II) with phases: Prophase, Metaphase, Anaphase, and Telophase (PMATx2); involves separation of homologous chromosomes and sister chromatids.