Questions tagged [sexual-reproduction]
Reproduction involving two morphologically distinct gametes, such as sperm and egg, where offspring inherit genes from two parents.
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Postulate that one sex will put more resources into reproduction than the other
What is the name of the idea that because one sex will put more resources into reproduction than the other, that sex will try to minimize the number of mates (choosing the best one) and the other sex ...
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Comparing the role of fathers in different species
In species where the male of the species is involved with the life of his offspring in what species is the role he takes is the same as the role of the mother, and in which species is it overlapping ...
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Considering Two Genes, Are There Only Two Possible Outcomes for the Four Gametes Produced After Meiosis, Regardless of Independent Assortment?
Is it true that for a single meiotic event when considering only two genes, there are only two possible genetic outcomes among the four gametes produced, regardless of whether the two genes are found ...
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Is there any research on whether a choanozoan might have invaded a similar enough holozoan to make the first metazoan?
My mind was piqued by the idea of endosymbiosis of a bacterium penetrating the cell of an archaean being a precursor to the advent of eukaryotes. And I thought that perhaps something analogous to this ...
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How does sperm gets oxygen in the female reproductive tract?
At the time of insemination, sperm along with seminal plasma enters in female reproductive tract and the plasma contains fructose for providing the energy to sperm
If the fructose follows just EMP ...
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Can citrate in semen be utilized as a source of energy by the sperm?
Prostatic secretions of semen include citrate as one of the component.
The role of citrate in motility has been suggested by some researches.
(Kavanagh JP. Isocitric and citric acid in human prostatic ...
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How does pollen grain lose viability?
If sporopollenin is such a resistant layer, how does pollen grain lose viability, even such easily in some cases?
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When is the sex of a human not determined by their chromosomes?
This might sound like a silly question, but what chromosomes determine whether a human is born a boy or a girl? I ask this because I got https://embryo.asu.edu/pages/sex-determination-humans when ...
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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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Why Sexual Reproduction instead of Gene Transfer?
So, as I understand it, the prominent theories for the evolution of sex are that it increased variation allowing for faster adaptation in evolutionary arms races, and that it gets rid of deleterious ...
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Does the X/Y sperm ratio in male ejaculates depend on circumstances of sex and who they are mating with?
Male mice are known to have different X/Y sperm ratios in their testis. Possibly, this phenomemon is not limited to the mice. However, can the males utilise that to their advantage?
For example, ...
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why do spirogyra turn brown after formation of zygospore?
in the sexual reproduction of spirogyra, the reproductive parts of the 2 spirogyras come together to form a structure called zygospore. after this formation spirogyra turns brown. why is it so? i want ...
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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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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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Do wolves mate with siblings?
I have just watched a "documentary" on a female wolf raising her cubs in the Alps. I found various aspects of the programme less than convincing, but one in particular puzzled me. The alpha ...
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Why do humans have sex for recreational purposes? [closed]
It never made sense to me why human beings crave sex other than for reproducing. It controls our society. It causes heartache, jealousy, anger, low self-esteem etc. Sometimes humans will have sex ...
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For animals with separate hermaphrodite and non-hermaphrodite populations which is more common, female + herm or male + herm?
I think the question already says it all. I know there exist animals that have both herm and female populations and other's with herm and male populations, I'm not personally aware of any animal that ...
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Can offspring be less genetically similar to the parent than more distant relatives?
I'd be interested in answers about any sexually reproducing species, but for simplicity I'm going to focus on humans in this question.
If the parents are very genetically different (i.e. the number of ...
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why are dizygotic twins genetically dissimilar
I am a high school student and I am a little confused in a topic related to dizygotic twins, I get to know that dizygotic twins are genetically dissimilar because they are formed as a result of two ...
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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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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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Is there any evidence for sperm parameters being connected to fitness of the offspring produced by that sperm?
In most (if not all) sexually procreating species the amount of offsprings a male can produce is limited not by the amount of sperm he can produce, but by the amount of eggs his sperm can fertilize (...
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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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What are these structures inside a cut open Allamanda blanchetti?
As suggested by @tyersome in my previous question on the same topic which I posted yesterday, I have cut open few flowers of Allamanda blanchetti
in order to observe if any reproductive structures ...
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Allamanda blanchetti fertilization mechanism
Here is an Allamanda blanchetti flower in my garden.
My question is based on the observation that the flower seems to be devoid of any reproductive structures, i.e., Stamen or Carpel, so how does it ...
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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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What causes the sound of climaxing bees?
I just saw the funniest video of bumblebees(?) having sex. (mirror) As they were getting it on, there seemed to be an almost audible 'moaning' coming from the pair. From what I presume it was a sexual ...
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Why do the two sexes have different reproductive costs and capabilities?
Is there an evolutionary explanation that shows why the reproductive costs are mostly on the female sex?
And therefore, why do males can potentially have more offspring?
Does that happen to create ...
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Is it true that recanalisation of the vas deferens, if any, tends to happen soon after a vasectomy (less than 1 year), and if so, why?
https://doi.org/10.1016/s0140-6736(00)02436-3 "How reliable is a vasectomy? Long-term follow-up of vasectomised men":
Most episodes of recanalisation are believed to happen soon
after ...
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If species are reproductively isolated, then how are interspecific hybridisations carried out?
during fertilisation there is compatibility test done so that both sperms and eggs are of same species. the zona pellucida of egg bears sperm specific receptor proteins(ZP3 receptor proteins) which ...
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Recommended books and articles on the origin and evolution of sexual reproduction? [closed]
I'm interested in learning about the origin and evolution of life on Earth. In particular, one topic that puzzles me a lot as a layman is the evolution of sexual reproduction, since the DNA mutations ...
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Does antibodies get produced in female body against sperms?
Our immune system produces antibodies against any foreign particles entering our body.In female body sperms are a foreign particle .Does females produce antibodies or some sort of chemical resistance ...
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Sperm formation - Frequent Ejaculations
I have visited various authenticated websites and other materials and learnt that a complete sperm development takes approximately 64 days.
My doubts :
If sperm truly takes 64 days to develop, how ...
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What is the developmental and health outcome of an XY individual with an SRY addition on their X chromosome?
I know that "XX male" syndrome occurs through various means, including the addition of an SRY gene in one of the X chromosomes. The developmental and health outcomes of such individuals can be ...
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In human embryology, what starts ovum cell division?
Maybe I am not using the correct search keywords in Google, but I cannot seem to find anything beyond basic information taught in schools about fertilisation of the egg by the sperm.
After the sperm ...
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Why is there such a long interval between ages of sexual maturity and of reproduction in female chimpanzees?
There seems to be some disagreement on the ages at which female chimpanzees typically reach sexual maturity and when they typically first give birth, but regardless, different sources seem to agree ...
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How does antagnostic coevolution work in ducks?
I recently learned that in ducks, the penis and vagina have coevolved: the vagina of the female ducks gets dead-end sacs and clockwise coils; the penis of male ducks become longest and its morphology ...
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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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Polyandry in birds
The Wikipedia article on Bateman's principle states:
Until recently, most bird species were believed to be sexually
monogamous. DNA paternity testing, however, has shown that in nearly
90% of bird ...
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Limitations of the Self-Incompatibility Mechanism in Plants
For a given plant species, how many types of S-loci exists to prevent self-pollination? I would like to know how often a plant stops fertilization process by other plants, thinking the pollens belong ...
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Evolution of the haplo-diplontic life cycle
From wikipedia > Biological Life Cycle:
haplontic life cycle - the haploid stage is multicellular and the diploid stage is a single cell, meiosis is "zygotic".
diplontic life cycle - the diploid ...
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Are Males the main evolutionary tool for production of genetic variation necessary for evolution?
What I'm saying here is just a personal reflection, that might turn to be gravely erroneous, actually I'm asking that because I didn't see it presented elsewhere.
Evolution is propelled by two ...
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Can threat to survival increase mutation rates in germline cells?
Can stress that is related to a threat of survival of a population of animals or plants in some environment, like due to hunger, thirst, fear from predators, etc..; results in an increase in average ...
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What are the (statistically) normal pH levels in the most-outer part of human sexual organs?
What are the (statistically) normal pH values of the outer skin/epidermis of human sex organs (groin/crotch) in the male and female? e.g male testes, female vulva, male glans, the enveloping epiderm, ...
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Spermatozoa and sperms
Does spermatozoa and sperm have different meaning?If they are same why do wikipedia have 2webpages ? But most websites mention them as the same thing.I am confused .Thank you in advance
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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?
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Why does inbreed produce a higher percentage of abnormal babies? [closed]
The babies of close (say, brother and sister, or cousin and niece) family members have a higher chance of being born with an abnormality than babies from non-family related men and women. Why?
