Stack Exchange Network

Stack Exchange network consists of 174 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.

Visit Stack Exchange

The biological process by which new individuals are formed.

2
votes
0answers
20 views

Are cloned spieces significantly more vulnereble to deseases than sexually reproducing species?

I would like to be able to compare the risk for species to go extinct implied by their reproduction mechanism in the very short term. Imagine we choose some species A that can reproduce both sexually ...
0
votes
0answers
22 views

Why did the menstrual cycle evolve to be a wasteful process? [duplicate]

Why did primates evolve its menstrual cycle to be such a wasteful process;Why did not a more efficient system develop which did not waste the resource in this manner?
1
vote
1answer
42 views

How long does each of the stages in meiosis take?

For each stages of meiosis (i.e. Interphase, Prophase I, ...), I wanted to know the time between each stages either in percentages or minutes. However, while I could find the cell cycle for mitosis ...
0
votes
0answers
14 views

What triggers the formation of slime-mold fruiting body?

I have attached a picture of this slime mold fruiting body which I took in my own yard. It is Mid-Summer (August), the air is humid but no rains. Earlier this month, a smaller one has appeared in one ...
6
votes
1answer
82 views

Very frequent multiple births in humans

18th century Feodor Vassilyev is said to have had children by two wives, each of whom only ever had twins, triplets or quadruplets. His first wife has 16 sets of twins, 7 of triplets and 4 of quads; ...
0
votes
2answers
41 views

What is the chance a given gene will end up in a given gamete?

Let us say a somatic cell had a desired gene. This somatic cell was replicated during interphase so that it had two of the desired gene. It then underwent meiosis. My question then is, what is the ...
0
votes
1answer
30 views

can self-fertilization in flowers be called asexual reproduction?

Suppose a flower having both male and female reproductive parts is self-fertilized then can this be called asexual reproduction...?I'm quite confused cause in this case the fusion of male and female ...
0
votes
1answer
53 views

Examples of points in evolution where two species stopped being interfertile? [closed]

Apologies in advance for not using the right terminology here; I'm not a biologist. This isn't for homework or anything; just curiosity. I'm wondering: at what point do two divergent species stop ...
1
vote
0answers
21 views

Correlation between menstrual period and lunar revolution

Is it just a coincidence that the the length of the entire menstrual cycle from one flow to the other lasts almost exactly as one lunar month?
2
votes
0answers
37 views

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 ...
2
votes
1answer
50 views

How do the chromosomes arrange themselves after fertilization in humans?

In human reproduction the male produces sperm containing 23 chromosomes and the female has the oovum containing 23 chromosomes , so after fertilization the zygote contains 46 chromosomes. What I want ...
0
votes
1answer
57 views

Does amount of sperm affect fitness of baby?

If there's a 3 day ovulation period in which to have intercourse, would it be better (to create a more fit/healthy baby) to have sex once and ejaculate more sperm than have sex three times with ...
1
vote
0answers
48 views

Has Epipremnum aureum lost its ability to reproduce sexually?

In this recent question the shy flowering nature of Epipremnum aureum (Golden Pothos) was discussed: Where can I find a picture of the inflorescence of Epipremnum aureum (golden pothos)? To ...
0
votes
1answer
79 views

Advantages of Monogamy over Polygamy and Vice Versa In Nature?

Some animals take on a single partner, possibly for life, while others have multiple partners over their lifetime, possibly even at the same time. What are the advantages to each approach, and how ...
1
vote
1answer
148 views

Spermatogenesis question

I found this diagram in my textbook regarding the process of spermatogenesis. But, I doubt if the labelling done is correct or not. Especially, I can't figure out any difference between the cells ...
0
votes
0answers
12 views

Sexual reproduction in plants

The female gametophyte of angiosperms is 7 celled and 8 nuclear. My question is Is it possible for the male gamete to fuse with the other haploid cells rather that the egg cell?
2
votes
0answers
17 views

Do marsupials ever die in childbirth?

Question: Do marsupials ever die in childbirth? Obviously the notion of there being a linear ordering of "least advanced" to "most advanced" life forms isn't correct. Still, often marsupials are ...
2
votes
0answers
22 views

How did genome replication first synchronise with cell division?

It is obvious that cell division in living organisms is now synchronised almost perfectly with DNA replication and, furthermore, the line of division has to intersect exactly the space between the two ...
0
votes
1answer
57 views

Is it Theoretically Possible to Create a Male clone from the donor Cell of a Female?

I understand that Dolly the Sheep was created without the presence of a sperm cell. Instead, nucleus DNA from somatic cells of adult sheep were used. Since Dolly was female, i am assuming that the ...
-1
votes
1answer
86 views

When is Semelparous reproduction most likely to be favoured?

Under which of the following conditions is Semelparous reproduction (where organisms produces all its offspring in a single reproductive event) is most likely to be favoured? (A) Adult survival rate ...
1
vote
1answer
94 views

Genotypes of gametes produced by an F1 individual?

I have an urgent question as I have an exam tomorrow. I was skimming some past exam papers and one question came up which has me completely confused. A cross was made between a pure breeding ...
2
votes
0answers
29 views

why hens determine the sex of the chick?

So, I have an exercise where I have to correct the second part of the sentence. It goes like this: In hens, the sex of the chicken is determined by hen, because the hen is the heterogametic ...
0
votes
0answers
31 views

Are seeds alive and by what mechanism do they 'Spring back to life'?

Correct me if I'm wrong but, human and plant cells require, at least to my understanding, a supply of energy, water and other neutrients to survive and carry out functions (such as sell division). ...
1
vote
0answers
31 views

How diverse are the sperm cells of an individual male due to random mutations?

Due to the sheer number of sperm cells in an individual and the rate of mutations, are they likely to be incredibly diverse and encompass most of what we see across our species? For instance would it ...
2
votes
1answer
95 views

Minimum age to reproduce [closed]

How old does one (male and female human) have to be in order to reproduce Im thinking that it's 13 for a boy and 3 for a girl, is that right?
0
votes
0answers
17 views

I am looking for examples of polyandrous insects?

This is for a homework assignment, and yet I am not able find any references that can help me find example of polyandrous insects. Does anyone have any references or suggestions on where to look?
1
vote
1answer
33 views

Harvest honey without damaging brood cells [closed]

I want to make a homemade beehive, I want to know how to differentiate honey cells and brood cells, therefore, I'd like to know how can I organize the beehive so bees will create honey and brood cells ...
5
votes
1answer
78 views

What are these little leaves growing on these other leaves? (plant growing near the ocean)

I saw many of these plants while hiking on a hill facing the ocean in northern Taiwan. I've included a snapshot of a nearby part of the same trail to show it's rugged, wet, green, and rocky, and ...
0
votes
0answers
22 views

Fruit-producing water plant

Are there any water plants that grow fruit that is meant to be eaten? I’m specifically interested in plants that are not rooted permanently to the earth but are mobile for at least part of their life ...
3
votes
2answers
59 views

Human ancestor reproduction after chromosome fusion

I read somewhere that human chromosome 2 is the result of 2 primate chromosomes fusing together somewhere along our evolutionary journey. This is why we have 23 chromosomes while other primates have ...
3
votes
2answers
122 views

Could two women have a child through artificial insemination/genetic engineering?

This is something I just thought of while looking up stuff about matriarchies. I recall a comic series I heard of once, I think it was called 'Y, the last man'. In that story, all males (besides the ...
0
votes
1answer
25 views

Sugar metabolism in preserved/cryopreserved livestock semen

I wonder how can semen use di/tri-saccharide (e.g. sucrose, trehalose, raffinose) for spermatozoa metabolism in preservation/cryopreservation of livestock semen, since the semen itself never bring any ...
0
votes
1answer
37 views

Requirements for ability to reproduce

In my (albeit basic) biology classes in the past, we've learned about how, to reproduce, two organisms must have the same number of chromosomes. This has been verified by a few other websites I found. ...
3
votes
2answers
189 views

Do chromosomes change with time?

An offspring is 23 chromosomes of mother and 23 of father, if one of the mate learns say music after the birth of their first child— will their second offspring have better music skills than former? ...
4
votes
0answers
64 views

Ratio boys:girls born - how to explain?

My son studies genetics at school right now and they have been covering gender. It's well known that slightly more boys are born than girls. However, originally there's an equal number of sperm cells ...
3
votes
0answers
67 views

Do ovaries produce estrogen before menarche?

It is traditionally taught that estrogen is produced by the granulosa cells of the follicle. But before menarche, where does the estrogen come from? Is it from the thin layer of granulosa cells lining ...
9
votes
1answer
287 views

What animal has the longest juvenile period?

I just heard the following complaint from a comedienne. Humans are the only animal that is completely useless for the first twenty five years of life. Obviously this is just a joke but it is true ...
1
vote
1answer
41 views

How plausible would it be for animals to normalize the birth of monozygotic twins in their reproductive cycles? [closed]

I'm currently trying to develop the world of a sci-fi story I'm working on, and a concept I've thought of adopting with the environment and characters is a common breeding system where identical twins ...
3
votes
1answer
73 views

Exact meaning of the term “clutch”

When reading a Wikipedia article to do with chickens, I have come across the term "clutch", but I was not able to entirely figure out what this word means. I was wondering whether the term clutch can ...
-4
votes
1answer
116 views

Can 2 people give rise to billions? Adam and Eve 2.0 [closed]

With with the advancement of GMOs the idea of giving rise to humans from 2 people is possible making questions like this invalid? How many people are required to maintain genetic diversity? With ...
0
votes
1answer
66 views

How is it possible for a new species to evolve? [closed]

Suppose a new species is created from a random mutation that happened during an instance of reproduction in an existing species. How can that new species survive and flourish if there only exists one ...
0
votes
0answers
31 views

is it possible to create eggs from male skin cells?

According to this article, Eggs from skin cells? There is a technique called "in vitro gametogenesis", which they say could allow any type of cell to be reprogrammed into a sperm or egg. The ...
0
votes
0answers
35 views

How do sex and reproduction differ?

My biology book says that "some protists reproduce without sex and have sex without reproduction". Does that mean that sex is not the same as reproduction? Does reproduction involve the production ...
3
votes
1answer
73 views

Do hermaphrodites have more nerve fibers in their puendal nerve?

Recently I have been thinking, both the glans penis and the clitoris are the most sensitive parts of the body. They contain a lot of nerve endings. Do hermaphrodites share the nerve fibres between the ...
0
votes
1answer
144 views

Reproduction in horses and donkeys

How are horses and donkeys able to interbreed and produce a mule. Don't their genetypic variation or chromosomal difference prevent them from doing so? If not, then why not?
0
votes
0answers
347 views

What is the difference between apomixis, agamospermy and apospory?

Some websites say agamospermy is just a synonym of apomixis but the definition of both terms is different. Others give almost same definition of apospory and agamospermy while also saying that ...
0
votes
1answer
43 views

Pseudoautosomal regions of the X chromosome showing heterozgyosity

I've always had questions for myself about sex differentiation, mostly on account of an unusual history & puberty. I won't go into details, but needless to say it was unique. My question is... I ...
1
vote
1answer
686 views

Why are male gametes and female gametes not equally sized

Why is it that male gametes are smaller and produced in larger quantities than female gametes that are large and lesser in number. Why aren't the gametes equally sized, or their sizes the other way ...
2
votes
0answers
317 views

Can telegony happen in humans like in Telostylinus angusticollis?

Is it possible for a human male to transmit features of his phenotype via non-genetic semen-borne factors to his mate's subsequent offspring sired by another male? As it happens in flies (Crean et al.,...
0
votes
0answers
83 views

Amphibian oocytes remain for years in the diplotene stage of meiotic prophase. Resumption of meiosis is initiated by which hormone?

A developmental bio book states that "Resumption of meiosis in the amphibian primary oocyte requires progesterone. This hormone is secreted by the follicle cells in response to gonadotropic hormones ...