Biology dealing with study of reproductive process, especially in higher animals. Closely related to reproductive endocrinology.

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Why can't gametes of one species fuse with that of the other species?

I have read that gametes of one species cannot fuse with that of another? For example the sperm of a dog can't fuse with the ova of a cat or a horse?
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24 views

Fruit Fly Hybrids

I have a food waste bin in which I put fruit scraps. The fruits come from all over the world, mainly Europe though. I'm in the UK. I assume the fruit Fly eggs are already in the fruit, in which ...
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36 views

Is there a mechanism by which mammals lose interest in a partner after mating?

I'm reading the book called "Cupid's poison arrow", which revolves around a rather simple assumption: most mammals, including humans have a genetic program that is responsible for ever increasing ...
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29 views

Negative association between habitat quality and reproductive success in birds

I'm looking for bird studies that have found either a negative correlation or no correlation between habitat quality and reproductive success. Or in other words, bird studies that have found that ...
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129 views

Isogametes and oogametes

I have found the following definitions of different types of gametes: isogametes: gametes looking and behaving the same; heterogametes: gametes different in size or in behaviour; oogametes: gametes ...
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50 views

Mating types in fungi (and somatogamy)

I would have some related questions about the mating types of fungi. Does a single spore generate a mycelium possessing only one mating type? If it does not in general, do Ascomycota and ...
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1answer
21 views

Do females retain oogonia after puberty?

Oogonia are the precursors of oocytes in females present during embryonic development. I was wondering whether these stem cells are still present in the ovaria at puberty?
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59 views

What is the trigger of pollen tube formation when the pollen is on the stigma?

What is the mechanism of pollen tube formation when the pollen is close to the stigma ? Is it because of chemotaxis? In other words, is the growth triggered by some chemical substance that is ...
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31 views

What is the developmental basis of the placental sac?

The placental sac is the organ that provides nutrients to the embryo from the mother. My question is that, since this obviously involves a lot of complexity, where does the sac originate from ...
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from an ageing reproductive stem cell's DNA to baby's “brand new” somatic cells' DNA

On the one hand, somatic cells's DNA age as life goes on, mitosis after mitosis, and that is reflected into reduced telomeres. On the other hand, during life, reproductive stem cells must age too. ...
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76 views

How can a drone be male?

A drone bee is male and is the product of only a queen bee. How is it that the drone bee can be male. I know that a drone is produced by an unfertilized egg, but this does not explain where the two X ...
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1answer
50 views

Why does uterus have to be prepared every month for fertilization?

I'm just curious why it has to happen every month when the uterus could have been prepared from the beginning and kept that way throughout life or till a certain point. But why make and break it every ...
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267 views

Why are sperm cells not attacked by the female immune system? [duplicate]

Whenever a foreign particle enters into someone's body, it is attacked by the white blood cells. I just want how it is that, when sperms enter the female body, they are not attacked by the the woman's ...
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3answers
193 views

How does menstruation proceed during one period?

I'm simplifying things here: A. Does a woman bleed constantly, like a drop every 10 minutes? Two hours without pad or tampon and your underwear is dirty? or B. Does a woman bleed suddenly a ...
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2answers
267 views

Why do we have more male infant born?

For every 104 male babies,we have 100 female babies and there is a Statistics which is more reliable (we have 997 female infant born per 1000 male infant born). what's the reason? why do we have male ...
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2answers
2k views

How was birth control realized in ancient days? [closed]

In ancient days, there were no birth control methods like condoms or contraceptive pills available. How did they control pregnancy?
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2answers
369 views

The gender of offspring of Twins?

Given identical twin males, Michael and Douglas, Douglas and his wife have four children, all of whom are girls. Michael and his wife have only one child, a boy, and are expecting another. What are ...
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2answers
609 views

How is menstruation not suicide in the wild?

Watch any wilderness special for more than a few minutes, and you'll notice a familiar pattern: when a predator catches the scent of blood on the wind, the hunt is on. Wounded animals make the best ...
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1answer
165 views

Why are hard boiled eggs so homogeneous?

A eukaryotic animal cell is a complicated piece of biological machinery. Some major structures inside of the cell (see the image below) include: the nucleus, mitochondria, Golgi vesicles, and various ...
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Creating Sperm via cell culture adaptation

I am wondering if it is theoretically possible to create "artificial sperm" via cell culture adaptation. That is at very high level, can you replace the genes of one sperm cell with those of another ...
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3answers
650 views

What exactly does adaptive mean?

This is a quote from Dey et al 2014: Hatching asynchrony is thought to be adaptive because... What exactly does adaptive mean here? Does it mean hatching asynchrony has fitness benefits? Or does ...
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0answers
85 views

What is the main challenge in creating a chemical male contraceptive?

More than 50 years after hormonal contraception for women was invented, a contraceptive pill for males is still not available. With the obvious major biological differences in mind, why does it appear ...
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1answer
117 views

Why doesn't the sperm die if there is citric acid and acid phosphatases in the semen?

While studying I read that sperm needs alkaline medium for its survival.But when I studied the composition of semen it revealed that semen contains citric acid which acts as a sperm nutrient along ...
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1answer
35 views

Significance of prostaglandins in semen?

I am trying to figure out how prostaglandins in the semen relate to the female reproductive tract. More specifically, How does prostaglandins in semen help the female reproductive tract increase the ...
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79 views

Why do mammals in the wild retain the “trait” of menstruating with blood?

This question intrigued me a lot since if animals in the wild did have menstruation with blood flow, wouldn't all that blood be attracting every other predator in the vicinity?
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2answers
201 views

Can diploidy evolve in absence of sexual reproduction?

Theoretical question Can diploidy (or polyploidy) evolve from a haploid lineage in the absence of sexual reproduction ? For what theoretical reason? How can such evolution take place? Empirical ...
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84 views

Is “monosexual” still a valid term in biology?

I read an older article where they talk about species being strictly monosexual as opposite of being hermaphrodite, etc [1]. After an extensive googling and reading about how everybody has to be at ...