The process through which a biological organism grows to maturity. In certain contexts it can mean the changes the organism goes through over its entire lifetime.

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What would happen if there were no SOX9 in an XY human?

Would testes be produced? If SRY is functional, can it produce other proteins that can direct the production of testes, which may or may not be sterile?
2
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1answer
68 views

How does an embryo know where to grow limbs etc

For example you have a cell or already a bunch of cells. Those cell(s) divide and after several week you have a grown organism, for example a human with limbs, several different organs etc. However, ...
2
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0answers
58 views

How many proteins are synthesized in human body throughout life?

My idea to calculate this is: Define up to what age will do the calculation. (for instance 60) Determine how many cells born and died up to that point in life. (by type of cell) Determine how many ...
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1answer
27 views

Are there anatomical differences between male and female mammal brains before action of hormones?

is there any evidences of these differences during development stages prior to hormone driven sexual differentiation? mice studies ?
3
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1answer
32 views

What are the application areas of Pattern formation studies specific to biology? [closed]

I was reading about reaction-diffusion processes, morphogenesis concept by Alan Turing and works of Murray in describing pattern formation on animals etc. But one question which came to my mind was ...
5
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1answer
31 views

Components of the concept of Developmental Noise?

Developmental noise is a concept that correspond to the amount of possible phenotypic variance of a given genotype in a given environment. Intrinsic noise (aka Cellular noise) is a component of ...
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86 views

What is the smallest scale at which blood vessels, nerves and other structures are deterministic?

Super simple question, but I can't find the answer on the Internet (and I'm in a foreign country so the library is not English.) As the title says, what is the smallest scale at which blood vessels, ...
0
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2answers
73 views

Questions about the Evolution Theory [closed]

I'm trying to understand more about evolution theory. (I am coming from a mathematical background) What i understand till now is that the "improvement" of the dna is a purely random development and ...
7
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1answer
49 views

Is the number of legs in myriapoda determined entirely by the genome?

Myriapoda (comprising, among others, millipedes and centipedes) can have hundreds of legs (Illacme plenipes having up to 750 legs). Interestingly, the number of legs (or leg pairs) appears to differ ...
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27 views

How are the external stimuli which fixed action patterns and other “innate” behaviours are honed in on genetically encoded?

Kelp gulls peck at a red spot on their mother's beak. Geese and cranes imprint on hang gliders. Presumably, these processes depend on sensory primitives (red spots, triangular shapes), and these are ...
6
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1answer
133 views

Is fluoride toxic, and how worried should I be about it?

A recent flurry of "fluoride is bad!" posts are appearing on my social network news feeds. Usually I can simply ignore them after a brief look, but this one, stemming from a recent article in The ...
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1answer
46 views

What does “developmentally programmed” mean?

What does the term "developmentally programmed" mean? I can't seem to find a definition anywhere. What would the alternative (i.e. not developmentally programmed) imply?
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2answers
82 views

Are there special constants in biology that define organism's morphology?

In math, there are special numbers, like Pi (3.14159...) and e (2.71828...). In chemistry, there's numbers like avogadro's number (6.0221413e+23). For example a circle can be defined in terms of 2 * ...
3
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1answer
45 views

What happens to human dopaminergic reward system once a teenager becomes adult?

I've recently heard a podcast which explained teenage impulsivity and novelty seeking in part by "Lowering the baseline dopamine activity in the reward system" "Increase in dopaminergic reward in ...
2
votes
1answer
80 views

Development of vitreous humor

I have tried reading about development of vitreous humor but it is all very confusing. When does it first developed ? Does it renew itself ? Please provide reliable sources..
5
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3answers
186 views

Does our eyeball increase in size as we grow?

Does the size of the eye increase as we develop from the stage the complete eye first forms to infancy and then to adulthood ?
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0answers
62 views

Are there specific features of birds that cats/small predators are attracted to?

I've recently heard a podcast, in which a professor describes one of the theories as to why we like abstract art. In his talk, he mentions an experiment with seagull chicks, in which the seagull ...
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0answers
29 views

Purpose of certain genes in embryonic development [closed]

(Please correct me if I'm wrong on any count here). As I understand it, development requires the action of numerous genes and proteins. My textbook has described it as being almost reminiscent of a ...
11
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1answer
94 views

Beginning of the urogenital system

Are any invertebrate nephridia (proto/meta) homologous with vertebrate kidneys in the sense that embryologically they also begin together with the genital system? When did the embryologic association ...
5
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2answers
216 views

Why is Portuguese man o' war considered a colony?

The wikipedia entry on the Portuguese man o' war says: ... the Portuguese man o' war is ... not actually a single multicellular organism but a colonial organism made up of many highly specialized ...
3
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1answer
91 views

Drosophila melanogaster eclosion

Is there any published data which shows the number of Drosophila melanogaster fruit flies eclosing (hatching out of the pupae) against time since egg oviposition? I'm thinking there should be ...
4
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2answers
126 views

How does the colinearity of the HOX genes determine the body plan of an organism?

I was recently reading about colinearity in the HOX genes that give an organism its high-level body plan (where the order of the HOX genes on the chromosome follow the head-to-tail order of body ...
3
votes
1answer
43 views

Where can I find a full genealogy of human cell types?

It is said on Wikipedia, that the precursor of blastocyst is a morula, and that the precursor of morula is a zygote. This gives us the part of genealogy tree of cell types. Unfortunately, no full ...
5
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0answers
153 views

Cytoplasmic determinants - protostomes and deuterostomes

Cytoplasmic determinants are spread unevenly in the egg, and so when embryo starts forming (cells start dividing), the determinants are also unequally divided between cell. This unequal distribution ...
2
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1answer
339 views

How many consecutive cell divisions are required to form the adult human body from the single cell zygote?

The preferred question would have been what is the total number of cells in a full term human foetus and how many cell divisions are required to reach that number. However estimates of total cell ...
2
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1answer
25 views

How do processes of one osteocyte establish contact with processes of the adjacent cells within the mineralized matrix?

Are the processes and canaliculi formed and contacts established after the osteocytes are embeded in the matrix or are they formed during the embedding process itself. Is there any evidence to suggest ...
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2answers
41 views

Which part of the genome are the developmental sequences of embryogenesis located?

Which part or parts of the the genome are the sequences located. Are they spread across the chromosomes? If so how are they accessed sequentially with precision during embrygenesis?
3
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2answers
97 views

Why ducklings are yellow?

Why ducklings are yellow, what the evolutionary background for this? How could it help to survive? UPDATE I agree with comment below, I did remember then that ducks are wild animals too (when I ...
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0answers
31 views

How did specialized nerve-based behaviors emerge in organisms? [closed]

There are quite a lot of diversity in behaviors of animals and lesser organisms, like mating, hunting, feeding, hiding and avoiding predators. At the same time I know that many hormones like ...
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0answers
53 views

Is there a realtime molecular clock within the genome to co-ordinate the developmental sequences in an embryo?

It is difficult to assume that the massive number of co-ordinated developmental sequences in a developing embryo is controlled by molecular signalling alone. Is anyone aware of a molecular or ...
0
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1answer
500 views

When can a virus modify DNA in every cell of a living organism?

I've recently heard about experiments with brain tissue, where a virus is introduced in a rats brain, causing a "glow when electric charge is present" protein to be created. This protein then helps to ...
2
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1answer
54 views

How do cells figure out the big-picture shape?

I'm wondering what makes cells to divide (and stop) in such a way that they make our hands the shape that our hands are...
2
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1answer
199 views

which exact mechanism triggers the first cell differentiation after n divisions?

I would like to understand which mechanism triggers the first cell differentiation after n divisions. I read previous articles on SE and Wikipedia articles on cellular differentiation and ...
3
votes
1answer
111 views

Method to recognize the age of a firebug from the pattern on its back

Can I recognize the age of a firebug from the pattern on its back? If yes, what pattern shows what age/stage? Below is what I extrapolated from Wikipedia, but is there a more precise scale with more ...
4
votes
1answer
98 views

How animals maintain their body shape after development to maturity?

I've recently read a book on evolutionary-developmental biology for laymen, and it described how a fetus is progressively divided into more refined zones of genetic activity. These zones, kinda like ...
0
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1answer
207 views

How does hair grow and is it similar to how grass grows?

If I recall correctly, nails (finger nails or toe nails) grow by adding matter at its base. So for instance, if you would draw a dot at the very bottom of your nail, it would end at the top in a ...
2
votes
1answer
446 views

Manipulation of gene expression using VP16 fusion and engrailed fusion to a transcription factor?

Today, a presenter briefly mentioned that gene expression in sea urchins during development might be manipulated using VP16 and engrailed fusions. On a slide, it said that expression might be ...
0
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1answer
81 views

When is wing growth in the bat complete and how soon can bats fly after wing growth is complete?

I was reading this paper by Cretekos et al (2008), in which they state that wing development in the bat is not complete until after birth - the wing continues to elongate postnatally. This would ...
5
votes
2answers
426 views

What metabolic activities are performed by a developing human fetus's liver?

I understand that organ function varies with the stages of development. Does a fetal liver EVER perform lipogenesis, gluconeogenesis, make bile, etc? Or does it only begin performing these actions ...
2
votes
1answer
115 views

What's the difference between a free chromosome fragment and an extrachromosomal array?

This is reference to a review on C. elegans mosaic analysis by Yochem and Herman, in which the authors make a distinction between free chromosome fragments and extrachromosomal arrays. For the ...
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0answers
34 views

If a receptor is inhibited throughout embryogenesis, could there be observable phenotypic differences in the adult?

So I read a journal article entitled "Maternal hypoxia and caffeine exposure depress fetal CV function during primary organogenesis" (Momoi, et al., 2012) and in essence the article speaks of the ...
4
votes
2answers
352 views

Question about cell signaling pathways (RTK, Jak-Stat, SMAD, etc)

I am in an embryology course right now and we've just started covering cell-cell communication in development. We were talking about the roles of the various cadherins and their discoveries but we got ...
6
votes
1answer
213 views

Primary cilia: what cell types have non-motile cilia that migrate?

My understanding is that there are two broad categories of cilia: motile and non-motile (also called primary. Examples of the former include sperm flagella and the cilia of epithelial cells that ...
8
votes
1answer
225 views

What prevents a pregnant woman's immune system from recognizing her fetus as nonself (and attacking)?

I'm familiar with the scenario of Rh- mother with Rh+ fetus having complications (more so after her first child), but that's not what I'm curious about. I want to know mechanistically why a pregnant ...
14
votes
1answer
330 views

Fibonacci sequence in nature, truth or just wishful thinking?

I'm reading a bit on the Fibonacci sequence in nature, be it the golden ratio or the golden spiral forming over and over again in biological structures, and then I came across this online article by ...
3
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3answers
1k views

Why does the apex of the human heart usually point to the left?

In the majority of human beings, the apex of the heart (left ventricle) points towards the left side of the body. Sometimes however (approx. 1/12000 births), a person is born with a condition known ...
10
votes
1answer
573 views

Could a fetus properly develop in micro/zero-gravity?

I suppose another way of looking at the question is: how important is gravity for the development of mammal fetuses? And if things would go wrong, what sort of things would they be, and what would be ...
6
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2answers
402 views

How do cells “know” what “type” to differentiate into?

I have been reading about Townes and Holtfreter's work in 1955, in which cells are dissociated from a blastocyst in an alkaline solution then mixed together and spontaneously reaggregates based on ...
4
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1answer
124 views

How does sex differentiation work in Paracerceis sculpta, the sexually tetramorphic isopod?

Paracerceis sculpta is a marine isopod species known for its unusual reproductive strategy: female: medium-sized; lives in harems run by an α male α male: large; keeps a harem of females β male: ...
5
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1answer
91 views

Free-flowing cells and those that are stuck together?

I've been thinking about the development of an embryo from the zygote stage. How is it that when cytokinesis takes place at that stage, the cells all stick together in a little ball, but later in ...