The biological process by which new individuals are formed.

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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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9 views

What did William Harvey discover from experimenting with deer?

On his wikipedia page, I read the following: In particular, Charles' hunting expeditions gave Harvey access to many deer carcasses; it was upon them that Harvey made many observations and ...
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58 views

Does reproduction cause aging ? Is aging just a strategy to increase reproductive success in all organisms? [closed]

Background for why I am asking this: I read a book—modern biological theory and experiments on celibacy— which uses life history theory to imply that reproduction is the reason why organisms grow ...
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1answer
40 views

How is excess semen removed if ejaculation does not occur?

There are some attempts to answer the question that I found via cursory Google search, but none of them were appropriately sourced. This site claims that they are "recycled like blood cells", but ...
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22 views

Breeding Southern Right Whales Genetics

I don't know much about biology. I just like watching David Attenborough videos and this made me curious. I just watched this video about breeding Southern Right Whales, and these two quotes puzzled ...
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14 views

Function of prostate gland and seminal vesicles

Multiple sources (my textbook, internet, videos) have been confusing me as they state various things. Which structure produces most of the semen and produces carbohydrates for the sperm; the seminal ...
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64 views

What animal produces male gametes by mitosis?

The following question came up in my biology examination but I could not answer it: "What animal produces male gametes by mitosis?" I know that some plants produce their gametes by mitosis in ...
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1answer
42 views

What's the difference between evolution fitness and reproductive success?

What's the difference biological fitness and reproductive success in the biological terminology?
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4 views

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 ...
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1answer
70 views

Why do chickens continuously lay unfertilized eggs?

As per subject: why do chickens continuously lay eggs even if they are not fertilized? Is this sort of behaviour found in other species of birds (or other egg-laying animals), or only in chickens? Is ...
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2answers
78 views

Do babies conceived naturally or artificially have any differences in long-term health?

Are there any long-term differences in children conceived via artificial insemination or sexual intercourse, pending that the mother successfully delivers the child?
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39 views

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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3answers
101 views

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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64 views

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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145 views

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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0answers
25 views

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 ...
5
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1answer
151 views

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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12 views

Does the spermatogonia divide to form primary spermatocyte or grow into primary spermatocyte?

I have two contrasting sources. One says that a spermatogonia 'divides' into two primary spermatocytes. The other says that there are two types of spermatogonia, one of which 'grows' into a primary ...
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36 views

How many children could Hunter-Gatherer support?

Hunter-Gatherers, to my knowledge, have to cover a fair amount of ground in order to be able to live off the land. This ought to have a placed a limitation on the number of children that they could ...
5
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1answer
369 views

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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2answers
225 views

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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1answer
41 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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1answer
45 views

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 ...
4
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2answers
59 views

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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1answer
60 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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1answer
60 views

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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353 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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52 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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1answer
69 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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46 views

Which sperm fertilizes the 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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72 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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60 views

What genetic link would cause a human to have a extra vertebra? [closed]

Most people have five vertebrae in their lumbar (lower back) region, which are named L1 to L5. However, some people possess an additional lumbar vertebra located below the L5. This extra vertebra, ...
3
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2answers
173 views

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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32 views

How can my baby DNA be “brand new”? [duplicate]

If it is assumed that "over time, our body and our DNA get damaged until we can no longer function properly", how is it that if I make a baby at the age of 40 with a partner of the same age, our baby ...
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3answers
109 views

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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3answers
79 views

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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0answers
15 views

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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2answers
222 views

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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1answer
11 views

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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2answers
44 views

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
58 views

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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43 views

Why do earthworms cross-fertilise being hermaphrodite

Although the earthworms are hermaphrodites, they dont di self fertilisation but crossfertilisation. What is the logical reason behind them doing it?
5
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1answer
417 views

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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0answers
264 views

When does meiosis occur in flowering plants?

At what point in the development of a flower does meiosis occur?
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24 views

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 ...
2
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1answer
42 views

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 ...
8
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1answer
2k views

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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0answers
70 views

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 ...
2
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3answers
774 views

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 ...
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66 views

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 ...