BIOL 1510 Lecture Notes - Lecture 11: Acrosome, Genetic Load, Disruptive Selection
Lecture 11:
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Reproduction: Chapter 46!
happens because organism that decide to not reproduce ar not here, but the self replicating molecules!•
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Two main routes of Reproduction:!
Asexual Reproduction!•
original position!◦
you are actually swapping genes!◦
Sexual Reproduction!•
create a new fusion by the fusion of gametes!◦
sending a copy of your self!◦
Cost:!•
two fold cost of sex:!◦
Males are note reproductive and are ultimatly competing with females for resources!‣
Idea of sexual reproduction!‣
that produces female and male !•
only female can reproduce !•
your population will not grow over time and stay staggered !•
Females have to convert more ....!•
Idea of Asexual Reproduction!‣
can produce two daughters at the same time!•
Can have more reproduction, exponential growth!•
Benefit !•
there has to be variation for selection BUT selection constantly reduces variation.!◦
Selection requires variation, but with each generation your removing individuals!‣
Sexual selection can do this by having new source of variation and increasing this!‣
By recombination (creating new variants)!•
Means you get a weird combination of parents !◦
You have hidden variation because of this, genes that aren't exposed to selection !•
Asexual population only produces clonal, and cancels out mutation!‣
Accumulation of deleterious mutations in the gene pool!◦
the genome is copied so it will always be passed to their offspring !‣
will acquire this unpleasant mutation eabc time !‣
Called Muller Ratchet!‣
clonal species should evolve from cloning themselves and ‣
undoing their specie!
Not in sexual species !‣
because only summits half of your genes = reduce genetic load!•
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Gamete fuse together to make the next generation:!
BUT do not have to have males and females !•
they are a byproduct of sex!◦
Sexual reproduction is shuffling genes !•
originally was only one type of sex!◦
Gametes were evenly distributed and same breed type - Original Condition!•
Two things they need to do:!•
Find each other!◦
Need to have enough resource combines between them to fuel development...!◦
How are you going to have a lot of resources an deb balanced at the same time?!•
what happened is some individuals produces larger or smaller gametes.!◦
larger could fuel development!‣
Caused disruptive selection!◦
it is good to have two different species to specialize in either making small or large gametes!◦
= selection favoring either one!◦
now sexual selection on small gametes!‣
males are the bi product of sexual selection ‣
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*When you produce sperm you go to one to four sperm !
*When you produce egg you go form one to one !
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Males: Happens in testis !
the sperm cells are matured in the tube!•
the big cells make up the tube itself and grow within these host cells !•
nee dot be provisioned with resources !•
Happens:!•
primordial germ cells and migrate to your testis area!◦
migrate to mitosis right away!◦
end up as sperm stem cells which allow them to always be reproduced !◦
lead to rapid perferation!‣
secondary spermatocycle !◦
mitosis 2!‣
early spematitd!◦
differation of sperm !‣
Differences in sperm (39:00)!•
1. Tail (Flagella)!◦
2. Golgi Aperatus!◦
needs enzymes to turn into the acrosomes!‣
3. Formation of acrosome!◦
4. splits of a drop of the cytoplasm !◦
Sperm determines the sex of baby:!•
BUT it doesn't finish cytokinesis and all sharing ◦
a cytoplasm!
idea that the protein form the genes will be ‣
shared regardless of their genetic
combination!
Helps with separation!‣
Forms sperm trains to maximize speed ‣
through the female reproduction track!
sperm are incompetent until they enter the track!•
Females:!•
when undergo at mitosis ends at eggs cell but not stem cells like males.!◦
Primordial germ cell !◦
undergo mitsosis!‣
but then the eggs stop in their progress!‣
End with eggs stuck in mitosis 1!‣
For this reason women's reproductive system get worse over time !◦
Going to one cloning and split into two polar bodies !◦
Ganadotrophins:!•
drives spermatic genes and oogonium geneisis!‣
Folic stimulate hormone (FSH)!‣
confines a lot of testosterones to the testis!•
Lutinizing hormones (LH)!‣
The production of testosterones !•
Hyperthalomus!•
produce the ganatotrophin relaxing hormone (GnRH)!◦
leave hyperthalamus go to the pituitary gland and releases this !‣
Males!◦
Females!◦
gets eggs primed for reproduction!‣
is a process of having a batch ready and one being prepared!‣
*Eggs have a bunch of cells taking car of them stored in follicle !
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Mesocycle Creation:!
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Steps:!
Hyperthalmus starts kicking in dumping GnRH!•
Document Summary
Reproduction: chapter 46 happens because organism that decide to not reproduce ar not here, but the self replicating molecules. Asexual reproduction original position you are actually swapping genes. Sexual reproduction create a new fusion by the fusion of gametes sending a copy of your self. Males are note reproductive and are ultimatly competing with females for resources. Idea of sexual reproduction that produces female and male only female can reproduce your population will not grow over time and stay staggered. Idea of asexual reproduction can produce two daughters at the same time. Bene t there has to be variation for selection but selection constantly reduces variation. Selection requires variation, but with each generation your removing individuals. Sexual selection can do this by having new source of variation and increasing this. Means you get a weird combination of parents. You have hidden variation because of this, genes that aren"t exposed to selection. Asexual population only produces clonal, and cancels out mutation.
