Questions tagged [reproduction]

The biological process by which new individuals are formed.

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What is effect of sperm in blood?

Staphylococcus aureus, Streptococcus pyogenes, and Clostridium perfringens all produce hyaluronidase. Each of these bacteria are pathogens (use hyaluronidase as a virulence factor to destroy the ...
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Are seedless fruits considered life? [closed]

From school, I remember that for something to be considered life, it must be able to reproduce. With the creation of seedless fruits (such as watermelon), would this be considered life as they don't ...
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Difference between Fragmentation and Budding [closed]

I have heard about two terms stating similar things - Fission and Fragmentation . I know Amoeba undergoes fission and Fragmentation is done by spirogyra. So what's the main difference between them?
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if sperm contains only 50% of someone's DNA how can it be used to identify someone?

Is DNA so unique that 50% of it is enough to identify a single person?
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How only one follicle develops into graffian follicle?

I've studied that one out of many follicle develops into mature or graffian follicle. The fact which confuses me is that, since all follicles are in same ovary, close to each other with equal supply ...
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Why are mice with a single X chromosome and no Y chromosome males?

I was searching online and I read this article Mice can be male without Y chromosome and this is a part of it: The experiments demonstrate that there are multiple ways to make males, says Richard ...
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What is the function of the polar bodies produced during oogenesis?

Why are polar bodies produced during oogenesis in human females? I read that polar bodies are produced during meiosis so that the oogonium (or gamete mother cell) can be converted into a haploid ...
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Is the DNA different in each type of cell? What DNA is passed to offspring?

Our body contains many different types of cells and each of those cells have their own DNA (correct me if wrong) like skin cells their own DNA that makes them skin cells instead of muscle cells. So ...
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386 views

What is working definition for female infertility?

I've studied infertility and found that its quite complex to define. However, I came to know about a useful working definition of infertility; which was " Failure to achieve pregnancy". Few days later ...
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Male-Male competition limited to breeding season?

I'm currently reading about sexual selection in the context of evolution. Unfortunately, the focus is always on animal behavior during the breeding season. What is 'normal' behavior outside of ...
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Do only one or both pairs of homologous chromatids exchange genetic material during the process of crossing over?

To be specific: Assume chromosomes A and B are homologous. They've both replicated into A1, A2 and B1, B2 and have formed a tetrad at the equator (synapsis). Most textbooks show either A1 and B1 OR A2 ...
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866 views

What makes animal to continually reproduce? [closed]

I was reading about Trypophobia and reached to Surinam Toad's reproduction methods. Then I had this doubt- Why would animals want to reproduce so much? In case of humans we mostly have the offsprings ...
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Genotype of children conceived after stem cell transplant?

If you have sickle cell disease and have a succesful stem cell or bone marrow transplant, your blood type changes to AA. But what about your future children? Do your sperm or egg cells continue to ...
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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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501 views

When does lactation occur?

High levels of estrogens and progesterone antagonize prolactin’s effect on the mammary glands, and it’s only after the placenta has been removed and the levels of estrogens and progesterone has ...
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573 views

Corpus luteum during the luteal phase and gonadotropins

Does the corpus luteum operate independently of the hypothalamic-hypophyseal-ovarian axis? I know that hCG sustains the corpus luteum in the absence of FSH and LH, but in an ovarian cycle where there ...
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Why does it take many sperm for one sperm to fertilize an egg?

Hundreds of acrosomes must undergo exocytosis to digest holes in the zona pellucida. This is one case that does not bear out the adage, “The early bird catches the worm.” A sperm that comes along ...
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635 views

Acrosomal enzymes and the female reproductive tract

My textbook wrote that the reason why acrosomal enzymes are so securely contained within the sperm (thus needing capacitation to facilitate their release) is to prevent any premature release in the ...
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Are gametes determined by the sex of an organism?

In the Wikipedia article for biological sex, I read the following sentence. "The gametes produced by an organism are determined by its sex:..." However, is it not through the gametes produced by ...
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Are missing limbs hereditary?

So with my basic understanding of biology, DNA can change over time. Does this mean that if one (or both) parents have something major missing (like a limb), the kid will come out without a limb? ...
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Do adult humans exchange beneficial bacteria? If so, how?

Recently there has been increasing interest and research into symbiotic bacteria present in humans and human gut. I'm aware of two new discoveries: humans are surrounded by a unique cloud of ...
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what is the natural way of rose to propagate by its vegetative cells?

I have read that rose reproduces sexually. But I have also heard that it can propagate by its vegetative cells (vegetative cells in its root). Is this correct? If yes, can I know how does it propagate ...
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Why are female not competitive for reproduction like males?

I have wondered if competition for mate among males and the race among sperm cells would result in healthy offspring, why no such mechanisms exist among females and egg cells? (Even females are ...
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What is the change in ratio of histone to protamine in men with infertility called?

I am neither a biology researcher nor a student. In a paper (written by a biology researcher) I am translating into English, there is the following statement which, according to the text, must have a ...
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Why are so many spermatozoa produced when only one of them fertilises the ovum?

During fertilisation only one sperm can fertilise the ovum. So why so many millions of sperms are produced?? Isn't this a waste of energy?
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1answer
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Are progenies factually half-clones of the parents?

Given that a "clone" (if anything, in the context of human cloning) is taken to be, as far as I have understood, a specimen possessing the same genome as his "father/mother", aren't all "non-cloned" ...
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What is this Sacrificial Reproductive Strategy Called?

The reproductive strategy of salmon is 'suicidal'. Before breeding the males metamorph permanently into a form suited for the breeding season but unsuited for survival. The females devote so much of ...
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Zygote Implantation and Pregnancy Detection

In a normal pregnancy, the embryo (blastocyst) implants between 8-9 days after ovulation. My understanding is that it is able to implant because the fertilized embryo produces a hormone that triggers ...
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Heteromaternal Superfecundation - Any known cases?

Superfecundation in mammals (fertilization of two or more ova from the same cycle by sperm from separate acts of sexual intercourse) -- Is possible in nature from different fathers (Heteropaternal) as ...
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Can females be recreated from male DNA?

A chromosomal male is XY and a chromosomal female is XX. Now imagine if, one day, this world has only males - is it possible to "recreate" a female by using two X chromosomes from two different males?
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Why did life on Earth develop with two sexes? [duplicate]

If evolution gives us the best adapted organisms for survival of the fittest, why does so many of Earth's organisms require two sexes for reproduction? Shouldn't this have been bred out of our ...
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Why don't the apples seeds from grafted trees produce the same kind of apples?

As Wikipedia says: Grafting is a horticultural technique whereby tissues from one plant are inserted into those of another so that the two sets of vascular tissues may join together. In most cases, ...
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How often does parthenogenesis in mammals happen?

Probably everyone knows that mammals can't produce viable offspring by parthenogenesis. But there are reports of human chimeras (see: a human parthenogenetic chimaera) and it's known for mice to ...
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Why are siblings unidentical? (Which chromosome of the pair do gametes have?) [closed]

I know that a normal human cell has 23 pairs of chromosomes (total: 46). On the other hand, a gamete has only 23 chromosomes. Which chromosome does the gamete choose out of each pair? And if "One of ...
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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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Nature vs Nurture in Rooster mating dance: Are roosters lame dancers because they never learned any better?

I've seen, read about, or heard several avian courtship dances, flights, songs, and other rituals. They are general very impressive, fancy, and beautiful. Roosters, by comparison, are quite lame. The ...
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1answer
150 views

Can sexual selection operate in temperature dependent sex determining organisms?

Or more broadly, are distinct forms of genetic inheritance (ie. sex chromosomes) needed for sexual selection? My thinking was that since there are no sex determining loci, there could not be linkage ...
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Why can't gametes of one species fuse with that of the other species? [closed]

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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Why didn't humans evolve to reproduce identical twins all the time?

According to the selfish gene theory, it seems like because identical twins sometimes get produced, a mutation to a gene that says, "if you have an identical twin, be fully altruistic towards them" ...
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Albinism inheritance problem: what are the father's alleles if he got an albino kid?

Albinism is caused by a recessive gen "c". A normal man marries an albino woman. The first son happened to be albino. What are the possible phenotypes of the parents? What is the chance that their ...
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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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Big cat in heat for months?

In this documentary about a lioness and a leopard the leopard is in heat for months. https://www.youtube.com/watch?v=MGqmylkOuKw Usually a big cat would be in heat for 5 days and then not in heat ...
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What bacteria do unborn babies contain?

This Scientific American article states that "[human] infestation [by bacteria] begins at birth". This would suggest that unborn babies are free from any bacteria. However, if the mother catches a ...
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How long does conception take?

I know that conception is a multi-step process. A sperm fuses with an egg. Its contents diffuse into the cytoplasm. Dad's DNA is transported to the nucleus. Proteins are gradually made from Dad's DNA....
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Why do we produce so many sperm?

So apparently we produce roughly 300 million sperm daily. Is there a reason why this is necessary? Wouldn't a much smaller (but still large) number be sufficient? Like, one million?
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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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