Download - Module 9, lesson 3 reproduction3
Reproduction
Comparison of the 2 types
Sexual• 2 parents• Needs meiosis to occur• Variety among offspring
– More natural selection– Crossing over can give even
more variety
Asexual• 1 parent• Needs mitosis to occur• Can occur in an
environment where there are little organisms
• Offspring identical to parent– Less natural selection
Meiosis allows for Sexual Reproduction to have more variation due to:
Nondisjunction• Chromosomes fail to
separate during meiosis which allows for different chromosome numbers.
Crossing Over• A section of one
chromosome switches places with the same section from the other chromosome of the pair.
Bacteria mainly do asexual reproduction by binary fission.
However, they can exchange DNA which then counts as sexual.
Bacterial Conjugationwww.flickr.com/photos/ajc1/1103490291/
Conjugation by Paramecium
Paramecium join at the oral groove and exchange DNA.
Pollination
www.fs.fed.us/.../pollinators/birdsandbees.shtm
Sexual Reproduction
Male gamete= SpermFemale Gamete= Egg
Fertilized egg = Zygote
erin-moore.com/pages/06%20fertilization.htm
Animals
Animals can either do
– External Fertilization: Like a fish
Or
- Internal Fertilization: Like Animals