Questions tagged [reproduction]

The biological process by which new individuals are formed.

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13 views

Why do eels go through dams?

I was interested in eels after learning about dams. I learned that there are such things as eel ladders as there are salmon ladders for the animals to swim up the damns to continue their journey, but ...
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What causes the shape of the dense structure in this “giant squid egg” sac?

The YouTube video Swimming Next To Giant Squid Egg shows a giant egg of a squid and/or an egg of a giant squid. Text in the video's description includes the text quoted below, which indicates that the ...
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Can foraging worker ants become queens?

The TL;DR is in the subject line. The back story is as follows: I am combating ants in my high-rise apartment unit. One piece of online advice was to vacuum regularly, and pay attention to edges of ...
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Plant hybridization - cross clade cross pollination possibility

Is it possible for monocots, like dates, to cross-pollinate with eudicots, such as olives? What is the general rule for how closely related species must be to form hybrids organically?
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What is meant by Physarum polycephalum having 720 sexes?

There is currently some media hype about the slime mold Physarum polycephalum, which will soon be exhibited in the Paris zoo. This was my first time hearing about slime molds, but so far so good. ...
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After hysterectomy does FSH secretion stop?

This question came in an exam, and my reference book says yes, it does. But it hasn't explained why. If the ovaries are also removed, then the menstrual cycle should stop. In absence of hormones ...
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Why do flowers naturally reproduce with their own species?

I have always wondered why flowers reproduce with the same species naturally. Why can't the pollen grains get to a different species flower through via the wind, water, or insects?
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What's it called when a male seahorse gets “inseminated”?

I am looking for the scientific term for the process where a male seahorse receives eggs from the female. For example, we usually say, "the male inseminates the female with sperm." What is the correct ...
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Do large fathers engender a higher probability of caesarian section?

If a large father has a child with a smaller woman, i.e. 90kg and 45kg, are there higher chances that the baby will be too big to slip through the birth canal, resulting in a C-section?
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Is there an example of a species wherein the female lays eggs in the male?

There are of course many species which lay eggs in the bodies of another species and also many species where either the male is eaten after mating or the male dies soon thereafter. So it seems ...
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Why do four spermatids have different genomes?

It's been a while since my last class in genetics, so I've forgot most of it. However, I found myself studying human reproduction and I've the following doubt concerning spermatogenesis: the process ...
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Is mating between human and non-human primates theoretically possible?

I wonder if it is theoretically achievable to produce living offspring between a human and a non-human primate. Great apes have 24 pairs of chromosomes compared to our 23, however, it is known that a ...
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What's the difference between male and female?

As long as we only look at humans the differences are clear: males have chromosomes XY, produce sperm and don't get pregnant. Females have chromosomes XX, produce egg cells and bear babies. But when ...
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251 views

Sex and human's sexual urge.

Why is it necessary for humans to feel pleasure while having sex? Why is it that other animals don't need to experience it? Is it evolutionary ? Why do we mate for pleasure when it's so energy wasting/...
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Sexual Reproduction in Humans

Is the human egg cell (ova) considered motile? We know that is is not actively motile but it is transferred via the fallopian tube to the uterus. Does that make it motile?
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61 views

Difference between fertilin and fertilizin

I am confused between fertilin and fertilizin.Are these two same or different? Here are a few sources i referred Julian Lombardi (auth.) - Comparative Vertebrate Reproduction-Springer US (1998) Page ...
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Can ovulation and menstruation occur simultaneously?

Is that possible that ovulation happens in the time of actual menstrual haemorrhage in human females - let say in a case that woman has 21 day cycle and her menstrual period is 7 days? If yes, does ...
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386 views

Are the seeds in a single capsicum fruit genetically identical?

Hopefully not a too-basic question for the venue. I'm a chile pepper growing hobbyist and have spent some time searching around and reading up on pepper (angiosperm) reproduction, but I'm not getting ...
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Animal reproduction when resources are scarce

(This question is aimed at animals that take care of their young, e.g. dolphins.) As I understand it, most animals reproduce if possible. The only way they don't is because they run out of resources. ...
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Is the bulbourethral (Cowper) gland turned on during puberty or is it on at birth?

I am trying to find information about the bulbourethral (Cowper) gland and if it gets turned on during puberty or not. I tried asking several other online sites and they said they couldn't help. I don'...
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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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Why don't most life forms show uniqueness in progeny? [duplicate]

I guess everyone must have observed this. Dogs, cats, and most of all insects (including mosquitoes) appear more or less the same. Why is there so little variation in their offspring, unlike humans, ...
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How can space travel affect women’s fertility?

From Time: The reasoning behind the prerequisite, according to officials, is that spaceflight could potentially harm the women's fertility. How can space travel affect a woman’s fertility?
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Why do hydrophytes lack endothecium

So I read that endothecium is a layer in the anther wall and it usually contains layers of alpha cellulosic fibrous bands that help in the dehiscence of anther Further hydrophytes lack this layer So ...
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Looking for realistic representation of angiosperm sperm cells during pollination

I've scoured Youtube, google, and a handful of my botany textbooks for a cellular-scale photo, animation, or video illustrating an angiosperm sperm cell during pollination/fertilization. ...
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Does the Chorion Completely enclose the Amnion in Humans

When a human baby is born "en caul" (aka enclosed in the amniotic sac) the amnion detaches from the chorion and the baby comes out in the sac with the chorion still attached to the placenta. If the ...
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Are there insect species where the male occasionally attacks/eats the female after mating?

While I realize this would be a very ineffective propagation strategy, it could be an aberration that is occasionally observed in the same way that males are not always eaten. Could males "pretend" ...
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In men, why do over 80% of sperm have abnormal form? [duplicate]

Here is the percentage of normal forms among fertile mens according to the centile (Source: Cooper et al. 2010): 2.5: 3% 5 (below this is Teratozoospermia): 4% 10: 5.5% 25: 9% 50 (median): 15% 75: ...
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How do animals learns seductional behaviour?

I was curious how the gender behaviour, the male role or female role, is known in mammals. Do mammals instinctively know how to do seduce the opposed sex or do the animals learn it from their parents/...
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Why are dolphins born tail first?

I heard most dolphins are born tail first. I have read many explanations from books and internet articles and they said that dolphins are born tail first to prevent them from drowning. But now I don'...
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Is there natural occurrence of induced pluripotency / expression of Yamanaka factors and what is the evolutionary explanation of that?

Is there natural biological processes in which the full (full reprogramming into pluripotent state) or partial (partial reprogramming, stopped before point-of-no-return, preserving the functional ...
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3answers
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When is the second polar body extruded from the egg nucleus?

When does the second polar body gets expelled from the egg nucleus during oogenesis ? I know that it occurs after the entry of the sperm into the secondary oocyte but does it occur before the ...
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Is newly produced sperm healthy if there was previous DNA damage?

I read that sperm cannot repair DNA damage. So does this mean that if your sperm has DNA damage, then all of your sperm (whether present or future) has DNA damage? Or does it just mean that the ...
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How many mitotic divisions do haploid cells undergo before fertilization?

Background This question is about human physiology and gametogenesis. A spermatozoid is not necessarily the direct "offspring" of a diploid cell. Stated differently, a spermatozoid cell can be the ...
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Organisms with one, two, or more than two biological parents

I am interested in the generic names of organisms with one, two, or more than two biological parents. I don't know if the latter possibility is possible in nature, but if it could be, it would ...
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Mother's physiological response to baby crying

I have read several articles [1,2] that talks about the physiological response in mothers when their babies cry. Is there any studies performed and published that show that this is not true ? https:/...
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5k views

What will happen if a foetus is Rh- and the mother is Rh+?

If a mother has Rh-negative blood and her foetus has Rh-positive blood it will result in rhesus incompatibility and lead to erythroblastosis fetalis. What will happen if the reverse occurs, when a ...
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Can sperm cells penetrate the cell membrane of non-ovum cells?

Sperm cells have tiny bags of enzymes on their tip (the acrosome) which allow them to penetrate the ovum. My question is whether or not the process that allows sperm cells to penetrate the cell ...
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Are genes for producing heterozygotic twins sweeping?

The tendency for a woman to ovulate two or more eggs at once, which may results in a heterozygotic multiple births is the way I understand it at least to some part genetic. At least since the ...
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How do viable sperm persist for weeks?

Tests on men who have undergone vasectomies show viable sperm in their ejaculate weeks and dozens of ejaculations after ligation of their vas deferens. How is this possible? How long does a ...
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Can an organism exist as a single cell but come together as multi-cellular during certain times?

I am trying to remember a particular segment from a BBC special, about a single celled species. However, at certain times all the individual cells came together to form a structure, not unlike a ...
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Has an ectopic pregnancy's blastocyst ever been made to implant?

Has an ectopic pregnancy's blastocyst ever been successfully extracted from the Fallopian tube and made to implant in the uterus?
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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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What is the purpose of segments in citrus fruit?

What is the purpose of segments in citrus fruit? In my experience, each segment usually contains from zero to two seeds. I may have seen more but only rarely, if I remember correctly. What is the ...
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How does proximal centriole of human sperm function?

I've read that the human's unfertilized oocyte ( stuck at metaphase 2 of meiosis ) lacks centrioles and that it completes meiosis 2 after fertilization as sperm gives its proximal centriole. Then what ...
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55 views

How can inbreeding be used for selecting mutations?

I understand that inbreeding, after a number of generations of crossing genetically related individuals eventually yields homozygotes, however I can't seem to understand how it can be used for ...
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Does global sperm count decline also mean lower testosterone?

So I read about the sperm count decline in men in rich countries. I wonder if this is accompanied by other changes for example in testosterone levels or in other hormones linked with the reproductive ...
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How can twins be born months apart? [closed]

How can twins be born months apart? What is the science behind it?
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What are the advantages of sexual reproduction over asexual reproduction? [closed]

What are the advantages of sexual reproduction over asexual reproduction? How does variation influence ecological and evolutionary success?