Questions tagged [reproduction]
The biological process by which new individuals are formed.
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Size ratio of Drosophila bifurca gametes and implication for the definition of sex
I recently learned that males of Drosophila bifurca species have gigantic sperm cells, 5.8 cm long and they only produce few hundred such cells during its lifetime. This made me wonder if the male ...
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What signals the corpus luteum to degenerate once the placenta is formed?
I've been trying to learn what causes the corpus luteum to finally degenerate once the placenta is ready to take over (in other words what is the trigger or signal and where is this signal produced) I'...
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Is the offspring of two-sex plants a clone or a child?
Many common plants e.g. tomato, pepper; produce both male DNA carriers and female embrions. In the case that the plant is confined alone, do the resulting seeds carry a carbon copy of the DNA of the ...
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Does monoecious plants have bisexual flowers?
I used to think that monoecious plants have male(unisexual) flowers and female(unisexual) flowers on the same plant but on different locations. But recently I got to know that monoecious plants also ...
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What motivates an organism to reproduce? [closed]
What is the biological factor (gene or something else in case of humans) which motivates an organism to reproduce?
By reproducing the evolutionary success of an organism increases. But why would an ...
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Why Fertilisation occurs only in Fallopian tube?
The Ova is released and stops in the fallopian tube for the sperm..The Fertilisation occurs at the Fallopian tube, but as the zygote divides and forms an embryo, it attaches to the lining of uterus....
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When does a fetus become conscious?
I thought of asking this question in the Psychology & Neuroscience stack exchange, but I ultimately decided this would be a better stack exchange for it. When do the "lights turn on" in ...
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In the female reproductive system, is the labia minora / labia majora / labia as a whole the female counterpart of the scrotum in male?
I am confused about which labia is the counterpart of the male scrotum. Any help would be appreciated. My first question so pls try being more lenient with downvotes.
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Can anatomically modern human siblings have three decades of age gap?
In my story titled La Maison Sapiens, there is a HUGE nuclear family composed of the father, the mother, and their seventeen biological children.
To be exact, the male human being and the female human ...
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Why do dogs still have periods if they have an estrous cycle?
I recently learned that in most mammals, the endometrium is reabsorbed in the estrous cycle. Thus, I would expect dogs not to have periods (at least similar to periods that come from the menstrual ...
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How can drone bees be born from unfertilized eggs?
I am learning about Drone bees and I keep reading that they are born from unfertilized eggs.
Now here is my question: if eggs are gametes and therefore reproductive cells, how can they turn into a new ...
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Why does oogenesis have to begin in foetal stage itself?
In males, spermatogenesis begins after puberty and they retain this ability throughout their life time. However, in females, oogenesis begins and ends in the foetal stage itself and the female is ...
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How does the female body sense its own pregnancy?
I understand that after the fertilized ovum attached in the uterus the female body will not produce the required hormone surge for ovulation the next month. Therefore no new ovum will be sent down the ...
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Why does the Corpus Luteum produce more Progesterone than Estrogen?
In the human ovarian cycle, follicular cells produce only Estrogen in high concentrations (to my knowledge). Yet after ovulation and formation of CL, which should be the remnant follicular cell mass, ...
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Can all plants be reproduced through vegetative propagation?
I have learned that plants can be reproduced or propagated through vegetative parts but there is a question in my mind if we can each method for all types of plants. I don't know if all plants have ...
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Why is the process of releasing gametes in females different from that of males?
In context of humans, males produce sperms, store them (for few weeks? then regeneration?) and ejaculate them "on demand" but females can not do that. Females have an almost fixed pattern of ...
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What does this statement pertaining to fission mean?
I was reading about fission on Wikipedia when I encountered the following statement under Fission of prokaryotes section.
Like in mitosis (and unlike in meiosis), the parental identity is lost.
What ...
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In life history theory, does trade-off between reproduction and growth and maintenance imply longer health span for a sexually inactive organism?
The life history theory suggests that there exists trade-off between life processes like reproduction and growth and maintenance of the organism.
One significant trade off is between somatic effort (...
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Intersexual competition regarding energy investiture of offspring
A while ago I remembered reading about a species that had evolved so that the male sperm cells promoted the energy investiture of the female in this offspring upon fertilisation. Since this was a r-...
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Is being able to interbreed and produce fertile offspring a transitive relation in biology?
Being able to interbreed and produce fertile offspring is one criterion to decide whether two populations are of different species.
Are there 3 populations A, B, C such that A and B are able to ...
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Which varieties of Aurelia aurita do not have a polyp phase?
According to this "In some Aurelia aurita, the polyp stage does not exist.", but they don't cite anything. Is there a resource detailing life cycles of various jellyfish or do I have to find ...
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What happens to quality of breast milk when twins of two different sexes are born?
It says here in Scientific American
Mother's milk may be the first food, but it is not created equal. In
humans and other mammals, researchers have found that milk composition
changes depending on ...
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Using the law of independent assortment, why can't heterozygous parents make identical twins?
In a case where two parents are heterozygous, why can't any pairs of their children be identical twins? As the question asks, I tried to explain this using the law of independent assortment, which ...
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Do plants originate from a single cell
I read the generalization that life originates from a cell, and from my understanding animals, they originate from a single cell, produced as a result of sexual reproduction. And then life begins to ...
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Is there a name for the natural law that any population of a species will increase until it utilizes all available resources in the area it inhabits?
A squirrel population in a forest will only be as big as the available food source allows, and probably a little smaller after you account for predators, disease, etc. What is the name of the tendency ...
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Motion of Fallopian tube fimbriae
The fimbriae at the ovary end of Fallopian tubes are described as "sweeping" eggs from ovaries into the tubes:
When ovulation is about to occur, the sex hormones activate the fimbriae, ...
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How does a diploid sporophyte form in non-recurrent apomixis?
I came across this definition of non-recurrent apomixis which occurs in angiosperms-
In non-recurrent apomixis, both the egg-cell and embryo are haploid and embryo is developed directly from an egg-...
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Why do OX5034 GM mosquitos require the presence of tetracycline to survive? What does the drug do in this case?
I'm confused. Debug Fresno; why are the released mosquitos said to be sterile? from 2017 addresses male mosquitos released with a bacteria that will affect fertility of females after mating. They are ...
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How do honeybees requeen themselves?
It is said that beehives once queenless try to rear a new one by themselves. Beekeeping resources, books, websites, youtube videos, etc. have a very pragmatic human-centered view to the issue: what ...
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Why isn't the ovum reabsorbed into the body (like sperms) if it is not fertilised?
I have read that when sperms are not ejaculated out of the body, they are broken down and reabsorbed. Why can't the ovum be reabsorbed into the body instead of shedding it out during menstruation.
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Do some animals have a tolerance to the negative effects of inbreeding?
Are some animals more or less tolerant to inbreeding? By tolerant I mean do they have a genetic mechanism that allows them to inbreed and corrects for issues introduced through this? When I started ...
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Is human zygote unicellular or multicellular [closed]
Is the human zygote which is formed by fusion of sperm and egg a unicellular structure? Bcz at some places the 2 celled stage which is formed due to cleavage has been labelled as the zygote. So is the ...
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Are there any species whose descendants can meet their ancestors from 100 generations back?
I.e. Humans can sometimes meet even their great-great-grandparents, but are there any species that can be alive at the same time as their great-great-……-great-grandparents? I imagine it would be those ...
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Check simple human fetus answers
Based on this image and questions, could someone please check my answers?
Question 1: At which one of the following points will the blood passing the point be more oxygenated after birth than before ...
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Does lack of adaptations for sperm competition necessarily shows the species are monogamous/serially monogamous/polygynous?
On the one hand adaptations for sperm competition, such as large testes, mate guarding, etc. are used to support that female in species are promiscuous.
On the other hand we know multiple eusocial ...
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Multiple fission and spore formation
I came across this question today. In the B diagram, zoospores of chlamydomonas is given. Now my doubt is, are the zoospores formed by multiple fission or spore formation? If it is by spore formation, ...
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A study has found that cell phones cause infertility, is this something to worry about or is the study flawed?
Is this a worrying study, or is it flawed?
A study has found that cell phones are detrimental to male sperm quality (Lower sperm motility and sperm concentration). It’s original goal was to determine ...
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Reproduction in animals
Humans have acquired knowledge about their environment through many observations. Today, humans have wide variety of resources to gain knowledge about reproduction in human beings and other ...
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How does permanently modifying human DNA work? And how does it impact procreation?
So I read an article about a metabolic disease being treated with gene therapy, where they inserted corrective dna into the patient.
https://www.independent.co.uk/news/science/dna-permanent-change-...
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How do plants that reproduce with artificial vegetative propagation grow in nature?
How do plants that grow with artificial vegetative propagation grow in nature? Will they go extinct if humans stop intervening? e.g., Rose
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Flatworms sexual reproduction; one must be the mother and the other the father?
I watched this.
I wonder if both of these flatworms ever end up pregnant.
Earthworms are simultaneous hermaphrodites, meaning worms have both male and female reproductive organs, just like flatworms. ...
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How the vaccine based on "non replicating viral vector" is produced?
As I understand, this kind of vaccine is a virus that can infect the cell, start synthesis of proteins encoded by its genome, but cannot finish the replication cycle till the proper end. It can have ...
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Germ cells vs. gametes
Naively, I thought that germ cells are diploid (in diploid species like human/mouse at least). Then, germ cells undergo meiosis and become haploid. I thought this was the critical change that defined ...
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Why are so many species reproducing late this year?
Hope this question is OK for this site, couldn't see where else to ask it.
We've spent a few days out in the countryside recently, and have been very surprised at how many species appear to have very ...
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What is the difference between fragmentation and true regeneration?
I read in my book that Planaria (flat worms) undergo true regeneration.
Fungi, filamentous algae and protonema of mosses multiply by fragmentation.
What is the exact difference between fragmentation ...
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Asexual Reproduction Of sponges through endogenous or exogenous budding?
I was studying asexual reproduction in sponges and came across two website
Wikipedia of Gemmule and there is a line....
Only Endogenous Types of Buds develop into New Sponges.
Then as I was reading ...
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Monozygotic vs Dizygotic heteropaternal superfecundation
Update: I had a wrong assumption.
After triple checking, I now see that how ordinary monozygotic twins arise is 1 sperm and 1 ovum and then later the zygote splits up.
(1.1. and that that phil and ...
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Is there alternation of generations in animals other than cnidarians?
Are there other animals besides cnidarians that exhibit alternation of generations (having distinct sexual and asexual life stages)? If so, what are these animals? Further, why do so few animals have ...
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What large "package" is carried by this large spider underneath itself?
One night in early May in northern Taiwan a strange looking spider carrying a large white "package" underneath itself ran in front of me and stopped, so I photographed it. The package is roughly the ...
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What do the initial cell divisions look like in bird embryogenesis?
The germ disc in a bird (a disc because its a chordate) is a mystery to me. The ovum (yolk) is a huge mass of nutrients. It then gets impregnated. Then, what? What does the initial cell divisions look ...
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