BIO 30_Lec 2_Life Cycles

In animals, humans, and lower plants

• Terminal or Gametic meiosis
• Intermediary or sporic meiosis
• Initial or zygotic meiosis

meiosis occurs immediately before gamete formation

• Terminal or Gametic meiosis
• Intermediary or sporic meiosis
• Initial or zygotic meiosis

meiosis produces four spermatids

• Terminal or Gametic meiosis
• Intermediary or sporic meiosis
• Initial or zygotic meiosis

four spermatids differentiate to four haploid spermatozoa

• Terminal or Gametic meiosis
• Intermediary or sporic meiosis
• Initial or zygotic meiosis

an ovum fertilized with a sperm having 22 + X

• Male progeny
• Female progeny

an ovum fertilized with a sperm having 22 + Y

• Male progeny
• Female progeny

In flowering plants

• Terminal or Gametic meiosis
• Intermediary or sporic meiosis
• Initial or zygotic meiosis

anthers = microspore; pistil = megaspore

• Terminal or Gametic meiosis
• Intermediary or sporic meiosis
• Initial or zygotic meiosis

nuclei of a pollen grain

• first sperm
• second sperm
• third sperm
• first pollen tube
• second pollen tube

Three megaspores of the four produced by a megasporocyte will degenerate

• True
• False