BIOL 2040 Lecture Notes - Lecture 8: Teiidae, Komodo Dragon, Hieracium
3 May 2018
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Why Sex & Recombination?
October 15, 2015
Sexual Reproduction: involves meiosis and fertilization (gamete union)
Recombination includes:
• Crossing over during meiosis
• Independent assortment of homologous chromosomes into gametes
Asexual Reproduction (mitosis)
• Budding
• Spores (conidia)
• Bulbs (vegetative extensions)
Sexual Reproduction: 2N 1N
Recombination & Segregation:
• Recombinations between loci
o New combinations
• Segregations within a locus
o One gamete receives one allele and the other gamete will receive the second
allele
Consequences of Sex and Recombination:
• Sex and recombination break down associations of alleles at different loci
Many organisms are capable of asexual reproduction
• Ex. Whiptail lizard
• Amazon Molly
o All female
o Needs sperm from another species to activate reproduction
o Probably a hybrid of 2 sexual spp.
o Microchromosomes from males can be incorporated
• Komodo Dragon
o Asexually reproduction is possible but unusual
o Offspring all male, not clones
• Stick insects (Order: Phasmida)
• Daphnia – crustacean w eggs via mitosis
• Hawkweed (Hieracium) – creates seeds asexually
• Many dandelions are asexual
• Asexual reproduction by runners – ex. In strawberries = creates new plant from long
vegetative extensions, eventually becomes own plant
The Pattern of Sex/Asex.
on the Tree of Life
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