Lecture 9
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What are reproductive strategies
Different ways to propogate genes
What is Asexual reproduction
One parent, all genes are passed.
What is vegetative reproduction
When a plant grows from another plant
What is parthenogenesis
Reproduction from an egg, but no sperm.
What is Sexual reproduction
Two parents produce gametes that make a zygote.
What are the energy costs of sexual reproduction
Producing reproductive organs. Locating and courting a mate.
What is the fitness cost of meiosis?
You don’t propogate as much of your genetic material.
What are the benefits of sexual reproduction
Genetic variation Purging mutations
What is muller’s ratchet
As mutations continue through generations they become more frequent and more intense.
What is the red queen hypothesis
Evolution that keeps pace with the evolution of parasites.
How is sex determined?
The female produces the bigger gamete.
What is simultaneous hermaphrodites
When both reproductive organs exist together.
What is sequential hermaphroditism
When the sex of an organism differs through its life
How is self fertilization benefitial.
Can still reproduce without a mate.
When does hermaphroditsm evolve
When the hermaphrodite has a higher fitness than either sex.
What leads to higher fitness in hermaphrodites
Inexpensive gonads. Less mate competition
When do seperate sexes evolve
When the fitness of the hermaphrodite is less than that of either female or male.
When does seperate sexes have higher fitness
When the gonads are complex Mating systems are complex. Parental care is necessary.
How is sex determined?
Genetic sex differences Environmental cues (temp of egg in reptiles.) Biotic cues (whos around)
Why is a 1:1 sex ratio so common
Because the fitness of the rarer sex is higher so more of that sex will be propogated.
How are offspring not randomly selected for?
In some mamles, the male child requires more resources so they won’t be produced by a smaller individual.
What are the priorities of Females?
maximize # of eggs and quality of mates.
What are the priorities of males.
Maximize number of mates and eggs fertilized.
What is promiscuity?
Multiple partners no social bond.