Reproduction

SRJC, BIO 2.2, Swinstorm. Lecture exam 3

Sexual reproduction

fusion of haploid gametes to from a zygote

Asexual reproduction

new individuals are generated without the fusion of gametes

What are the four types of asexual reproduction?

• budding, pinches off from parent, like yeast

• Fission: parent splits into two: sea anemone

• Fragmentation: regeneration of body after breaking; starfish

• parthenogenesis: egg developing without fertilization

What are the three types of parthenogenesis?

Haploid, automixes, and apomixes 

Haploid parthenogenesis

developed into a haploid organism that may still reproduce. Male honey bees.

Diploid: apomixes

Do mitosis and produce female clones

Diploid: automixes

via meiosis, produce males or females who are genetically different from the parent.

How can parthenogenesis occur?

It requires a mating behavior in order for ovulation to occur. After ovulation progesterone is high so the female exhibits male like behavior. When progesterone is low the female exhibits female like behavior. 

What are the costs of sexual reproduction?

• only pass on half of your genes

• mate may kill you or have bad genes

• requires energy to find mate

What are the benefits of sexual reproduction?

• bad genes can leave more easily

• greater genetic variability leading to quicker adaptations

• ability to reproduce anywhere

What are some costs of asexual reproduction?

• bad genes stay in the population

• lack of genetic variation

• reduced adaptability

What are some benefits of asexual reproduction?

• they have good genes favorable for the environment 

• save energy since they don’t have to look for mates

• rapid population growth

Muller’s rachet

bad genes stay in the population and get passed on which decreases fitness.

Red Queen Hypothesis

If the predator is adapting and you aren’t, you will get obliterated

How can you reduce the cost of finding a mate?

• Simultaneous hermaphrodite

• sequential hermaphrodite

• be chosen when finding a mate

Simultaneous Hermaphrodite

containing both female and male reproductive systems. Annelids

Sequential Hermaphrodite

Starting as one sex then changing to the other under certain circumstances.

give examples of sequential hermaphroditism

• muscles begin as males as they age they become females

• Guppies store sperm in a much with sugars to self fertilize under the right conditions

• Angler fish fuse with their partner since they rarely see on another

Describe the process of Spermatogenesis 

Describe the process of oogenesis and follicle development

How does the timing of spermatogenesis differ from
oogenesis?

Spermatogenesis begins after puberty and goes into completion. Oogenesis starts before birth and stops at meiosis 1 prophase; after puberty it continues up until metaphase 2 of meiosis. oogenesis only goes to completion once it is fertilized. 

How does the number of gametes produced differ
between spermatogenesis and oogenesis?

Spermatogenesis produces 4 haploid sperm whereas oogenesis only produces 1 haploid egg with multiple polar bodies 

How might gametogenesis be related to sexual selection?

Oogenesis favor fewer but higher quality eggs where as spermatogenesis favors making a lot of sperm but not worrying about quality