The biological process by which new individual organisms are formed.
1
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1answer
47 views
How might IVF (and related technologies) alter epigenetic marks?
I was reading up on KCNQ1, which encodes a voltage-gated potassium channel, and I discovered that it happens to be only maternally expressed. This is regulated by KCNQ1OT1, a non-coding RNA, which is ...
3
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1answer
36 views
Are any organisms known to use meiosis I to create non-identical offspring asexually?
So, there are numerous species of animals who use parthenogenesis, but to my knowledge the reproduction is clonal. That is, the offspring are identical to the mother. Are there any documented cases ...
7
votes
1answer
234 views
Do egg laying animals experience a pregnancy?
Does a female animal that lays eggs experience a pregnancy-like period of time, where she will feel and behave differently as if she were fertilized and her body is prepared to lay a fertile egg, not ...
1
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2answers
80 views
How to know if a woman is fertile without actually making her pregnant?
How to know if a human female is fertile (can give birth to child in future) without making her pregnant? Any signs, tests?
1
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1answer
32 views
Parthenogenesis in Bees
Parthenogenesis is defined as:
"A type of asexual reproduction in which egg develops without fertilization to form a new individual."
If parthenogenesis takes place in bees, a drone or male bee is ...
1
vote
0answers
39 views
Can mammals from different species reproduce?
I'm curious on how genetically different can two animals be in order to reproduce. Could they belong to different species?
One example is the mule which is the offspring of a donkey and a horse, in ...
3
votes
0answers
15 views
A program for cell motility assessment with a batch process function?
Cell motility assessment is a branch of experimental biology or medical science. One example could be an assessment of treatment effects on sperm motility of an animal. The standard procedure involves ...
9
votes
3answers
608 views
Species with reproduction barriers that can both reproduce with a third species
To start with, I do not have a sound knowledge in biology or any formal education in the area.
I was told that one of the definition of a species is a reproductive barrier, which means that if two ...
7
votes
2answers
162 views
Do hormone drugs affect whether a person feels sexual attraction to males or females?
I know that ingesting testosterone and other hormonal drugs may stimulate libido and increase sexual desire.
But I wonder, if a man ingests female hormones such as estrogen, will he experience sexual ...
0
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0answers
34 views
Why aren't antheridia and archegonia touching?
Antheridia and archegonia are the two male and female gametangia, respectively, and they are found in bryophytes. To cause fertilization, usually a thin film of water must be present for the sperm ...
6
votes
1answer
91 views
How selfish is Dictyostelium slug formation?
Dictyostelium is a slime mold which is well known for having a single cell free living phase and other some conditions (e.g. when food is scarce) for forming communal piles of cells called 'slugs' ...
8
votes
2answers
815 views
Why are not all species hermaphrodites?
If a hermaphrodite animal (like slug, snail, etc) finds a partner they can mate immediately.
If another animal with "normal" reproduction (lets say a mouse) finds a partner they can only mate if they ...
3
votes
1answer
49 views
How can the child and the mother have different blood types?
As far as I know the fetus is fed by the umbilical cord which basically connects his/her circulatory system with the mother's in order to supply oxygen and nutrients. But how is this possible if they ...
4
votes
1answer
111 views
Which sex has higher variance of reproductive rate in modern societies - male or females?
Who has a more varied reproduction rate in modern western societies - men or women? The average rate is the same of course, but I wonder which sex have higher variance - higher variance means that ...
3
votes
1answer
76 views
Are there records of monozygotic twins in which one experiences androgen insensitivity syndrome
I have given my high school biology students the thought experiment of "What would happen if a researcher induced twinning of a female zygote and then replaced one of the X Chromosomes with a copy of ...
6
votes
2answers
226 views
Can positive and negative blood type of a couple lead to miscarriage?
I want to know can $+ve$ and $-ve$ blood group of a couple could be a cause of miscarriage in pregnancy?
4
votes
2answers
123 views
Is every part of a virus important for replication?
Is every component of a virus absolutely essential for its infection and replication in a host cell? Or can you just have parts of it to cause infection?
3
votes
1answer
55 views
Would ovoviparous to viviparous mutation have been gradual? How would that work?
It seems unlikely that an ovoviparous ancestor of mammals long ago could have had a viviparous offspring in a sharp one-generation dividing line, but what would be the gradual steps between egg birth ...
7
votes
1answer
230 views
When do most mammals mate?
Is one part of the day more prevalent then other when it comes to mammal animals mating? Is there an aggregating study that has been done to see if these living beings in nature mate mostly during day ...
3
votes
2answers
111 views
The probability of indirect human fertilization?
What is the probability of conception in situations when sperm isn't directly ejaculated into the woman's vagina, like:
The man's or the woman's hands come into contact with sperm, for example when ...
4
votes
1answer
110 views
What evolutionary pressures pushed Galápagos tortoises to mature so slowly and live so long?
I read that they take up to 40 years (in the wild) to reach the age of reproduction and are thought to live over 100 years, with one in captivity reaching over 170 years.
Can someone explain in ...
3
votes
1answer
20 views
Mutation in axillary buds of trees overcoming self-incompatability?
I seem to recall from either reading or lecture that there have been instances of trees that are self-incompatible accumulating enough mutations in an axillary bud that the resulting branch was able ...
2
votes
1answer
87 views
Has the age at which menopause occurs changed throughout history?
I was reading recently that the age of menarche has decreased in the last 150 years, and was wondering if the age of menopause in humans has also changed recently?
Would there be selective pressure ...
14
votes
3answers
308 views
Are human fetuses more likely to be male?
Question: From a physiological point of view, when sex is determined in a human fetus, is it equally likely to be male or female?
Studies in this area typically measure age at birth, where the data ...
3
votes
1answer
147 views
6
votes
1answer
88 views
Macromolecule levels in daughter cells after fission
When a prokaryote undergoes binary fission, how are the non-DNA macromolecules distributed between the two daughter cells? This is motivated by comments on a previous question and a G+ discussion. I ...
8
votes
2answers
150 views
Do twins “run in the family”?
My wife and I recently found out that we are going to have twins and so nearly everyone asks if we have a family history of twins. Now I know that the answer for me is that it doesn't matter—as ...
2
votes
3answers
327 views
Can the third sex be categorized as Male or Female?
Hijra are people who have a penis (not sure if sexually active) but look much like a female (perhaps for some feminine biological property). Wikipedia says they are "physiological males who have ...
8
votes
1answer
120 views
A timeline of the odds for survival for fertilized eggs and fetuses
I'm looking for data to build a timeline of the odds for survival of a fertilized egg, i.e.,
What are the odds it'll last a week?
What are the odds it'll last a month?
2 months?
(and so on ...
8
votes
1answer
93 views
Why does the gender of the parent species determines the species of a hybrid offspring
I've read a little about hybrid animals, and have been amazed by the fact that the gender of the parent species determine the species of the offspring, in some hybrids.
A male horse and a female ...
3
votes
1answer
68 views
Predictable microchimerism
I read in New Scientist recently that microchimerism occurs between previously born siblings and grandparents, not just the mother.
Do we know which parts of the genome are likely to be transferred? ...
3
votes
1answer
60 views
What are possible health risks to women having large numbers of children?
What is the possible health issue the women would face in this record?
The record for most children born to a single couple belongs to the
first wife of Feodor Vassilyev of Russia. In 27 ...
5
votes
1answer
122 views
Is ovum + ovum fertilization possible for human?
In humans is it possible to fertilize a ovum with another ovum from the same female subject?
I already found some works in which the ovum is fertilized by a somatic cell (see e.g. this ), but I am ...
2
votes
1answer
67 views
Are there any organisms with larva more advanced than adult form?
Usually adult organisms are more sophisticated than corresponding larva, i. e. frogs, mosquitoes, fish. Are there species where the opposite is true?
5
votes
1answer
116 views
Is sexual reproduction outside the same biological family possible? Ever successfully occured?
Is there an example of two species taxonomically classified in different biological families sucessfully sexually reproducing viable offspring? If not, is there an example of where reproduction ...
5
votes
1answer
196 views
Is it purely the nervous system causing vaginal lubrication (arousal)?
My girlfriend was watching some documentary on TLC about a paralyzed woman getting pregnant. I believe that woman still has some feeling, as she spoke about feeling the effects of a bladder ...
6
votes
1answer
68 views
Reproduction and defecation
In mammals and birds the external reproductive organs and waste removal organs see to be the same. Is this always the case with other animals such as insects etc...? Are there any good reasons for it?
...
1
vote
1answer
213 views
What animals stop other members of their species from mating and why?
(In particular primates)
I know chimps do. Powerful alpha males chimp would beat up omega males that they caught mating.
I know gorillas do. Powerful alpha males gorillas would beat up omega males ...
4
votes
1answer
54 views
Productive turnover and generations in the fruit fly
I was reading about the Lenski experiments on the evolution of E. coli bacterium and Dr. Elders's experiments on the evolution of the guppy.
These two experiments absolutely fascinated me, and seemed ...
2
votes
2answers
90 views
Gametes of two different species
I always wondered why gametes from two different species dont fuse together to form an offspring. eg a donkey (sperm) and a female dog (egg)
I know this is not possible but I'm just curious.
6
votes
1answer
141 views
Effect of spaying on the female cat organism and health
Veterinarians often recommend spaying a female cat if the owner does not want her to have kittens. What does biology know about the effect of spaying on female cats' organism and health (apart from ...
12
votes
1answer
477 views
Why do some mammals not have testes in a scrotum?
Coming from an evolutionary approach, Is the only purpose of a scrotum to regulate the temperature of the testes?
Knowing all mammals are warm blooded, shouldn't all mammals have testes in a ...
5
votes
2answers
246 views
How are the gene sequences of individual sperm and egg cells “randomized”?
What I mean by "randomized" is, in the place where an egg cell or sperm cell is made, what is the mechanism by which each one is not made identically? Though I am a layman, I'm pretty sure that if the ...
