Transcript Eukaryotic Life Cycles

Eukaryotic Life Cycles
BIOL 1407
Life Cycles
• Asexual Reproduction
• Sexual Reproduction
– Gametic meiosis
– Zygotic meiosis
– Alternation of Generations
Asexual Reproduction
• Watch Video #4, binary fission in Paramecium
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http://www.microscopyu.com/moviegallery/pondscum/protozoa/paramecium/t1/paramecium04.html
Photo Credit: Courtesy of Richard Allen @ http://www5.pbrc.hawaii.edu/allen/
Gametic Meiosis
• Diploid multicellular
organism
• Produces gametes
by meiosis
• Gametes = only
haploid stage
Gametic Meiosis
• Gametes always
fuse to form zygote
• Zygote grows into
diploid multicellular
organism
Zygotic Meiosis
• Haploid multicellular
organism
• Produces gametes
by mitosis
• Gametes always
fuse to form zygote
Zygotic Meiosis
• Zygote  meiosis
 haploid spores
• Zygote = only diploid
stage
• Spores grow into
haploid multicellular
organisms
Alternation of Generations
• Two generations:
– Multicellular
haploid organism
– Multicellular diploid
organism
– Life cycle
alternates between
the two
Alternation of Generations
• Multicellular diploid
organism
• Produces haploid
spores by meiosis
Alternation of Generations
• Spores grow into
haploid multicellular
organisms
• Haploid multicellular
organism produces
gametes by mitosis
Alternation of Generations
• Gametes always
fuse to form zygote
• Zygote grows into
diploid multicellular
organism
Question: Which Type?
The End
Unless otherwise specified, all images in this presentation came from:
Campbell, et al. 2008. Biology, 8th ed. Pearson Benjamin Cummings.