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15 Cards in this Set
- Front
- Back
- 3rd side (hint)
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What is sex for? |
Genetic Diversity, not reproduction. Crossing over, and independent assortment give variations. |
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What makes sex worthwhile? |
When a mutation in asexual happens, all offspring get it. Sexually only 1/2 get mutation - higher fitness. Also changing environment - > red queen |
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Red Queen Hypothesis |
Running as fast as you can to stay in the same place. An arms race. Changes in physical environment and biological environment. In the absence of sex you could not outcomplete your predator/prey. Ie. Aphids and plants. |
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Self-fertilization |
Leads to genetic diversity, but not as good as sexual reproduction. |
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Rotifers and tuns |
Lots of horizontal Gene transfer, they have genes from bacteria, fungi, plants, etc. Rid themselves of pathogenic fungus by drying out. Blowing the tuns to new habitats can escape the fungus. |
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Why are most things anisogamous? |
1) There may be higher fitness for making small gametes, because there are more of them 2) Big egg, big target Hypothesis (but sperm pheromones make egg 50x bigger). |
Means One big gamete and one small gamete. 2 ideas |
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Why is there gender? - - Anisogomous con'd. |
The control of cytoplasmic inheritance is the greatest contender. In a Cell there are three genomes: nuclear, mitochondrial, and chloroplast. Organelles reproduce independently of the cell, sperm only contribute the nuclear DNA, others from ovum. Darwinian fitness applies to these organelles reproducing independently, so different sized gametes is a strategy to limit genomic conflict. |
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Endosymbiotic Theory |
The eukaryotic cell engulfs the mitochondrial cell, but it is not dissolved. The cell supplies the bacteria with protection and carbon compounds, and the bacterium supplies the eukaryotic cell with ATP. |
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Evidence for endosymbiotic Theory |
Mitochondria and chloroplasts are about the same size as bacteria, reproduce by binary fission , independent of cell division. Contain a single, circular chromosome. Have their own ribosomes, which are like prokaryotes. Chloroplasts have two membranes, and prokaryote like features. |
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What is the key advantage to multicellularity? |
It allows increased specialization. |
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Pros and cons of internal fertilization |
Pro - Less dilution, less risk of desiccation. Con - you need new behaviors and new anatomy. |
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Internal fertilization |
Spermatophore - a gift wrapped box of sperm. Penis, or varieties of it. Sperm competition - second male displaces the first male's sperm. |
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Egg-laying vs. Live birth |
Oviparous - egg laying. Mother has higher chance of survival, but baby has lower. Viviparous - live bearing. Baby has higher chance of survival, but mother has lower. |
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Sexual cannibalism |
Black widow eats male, gets impregnated. Pennsylvania grassland spider eats male just for fun. |
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Traumatic insemination |
Bed bugs have a hypodermic penis, to stab the female's abdomen and inseminate her. The African bat bug also has this, but the females have developed a structure called the spermalege to guide the penis. |
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