11
votes
2answers
1k views

Do males of all sexual species have Y chromosomes?

I know for instance some cells are sexual, so, this got me wondering, do the males of all species that have distinct sexes have Y chromosomes?
9
votes
2answers
293 views

Could cancer be in itself a evolutionary process?

Could cancer be in itself a evolutionary process? Maybe in some way could it be a process of variation? Or would this idea be completely without support, if so, why? I don't mean that each case ...
5
votes
3answers
11k views

Is it possible for a child to grow taller than their tallest parent?

I have heard that offspring can't grow taller than either of their parents but I've also heard that sometimes some gene activation can skip generations. Is it possible for a child to grow taller than ...
28
votes
3answers
531 views

Is telomere length a reliable measure of health/lifespan?

Several companies are commercializing tests for telomere length such as this one here. I understand the basic mechanism for why telomeres shorten during DNA replication, but how good is the evidence ...
13
votes
3answers
462 views

How does a person get AIDS?

I am inquisitive to know about how a person contracts AIDS. Among the common masses it's still the belief that having sex with multiple partners causes the disease but that is not the case when read ...
12
votes
1answer
3k views

Why can hair grow without limit while eyebrow cannot?

I cut my eyebrow and it grows until reach a certain length. Hair can grow without limit. Why can hair grow without limit while eyebrow cannot?
11
votes
5answers
805 views

Introductory biology text for an outsider

I'm a maths major and I have an interest in learning biology. I know very, very little; I know how babies are made and that's about it. Could anyone recommend a stimulating text to read for it's own ...
10
votes
1answer
256 views

How are new people created from the DNA of an aged person. i.e. Why are we young?

The question "why do we age" has been asked numerous times. But why are we young? The cells of the adult human being are an age (time>0), but how can old cells create new cells that are younger than ...
8
votes
1answer
181 views

Why must a planet be in a star's “habitable zone” to have life?

I have seen many articles that talk about a star's "habitable zone" as the ring around it which is just the right temperature for planets to have liquid water, which is necessary for life. My question ...
6
votes
2answers
242 views

Why do we have two of some organs, but not all?

We have two eyes, but we don't have two hearts. Why do humans have two of some organs, but not all?
0
votes
2answers
223 views

Why even if all requirements for natural selection are met, it may not happen?

In the book written by John Endler Natural Selection in the Wild p. 4 it says that even if condition a, b and c are met, evolution by natural selection might occur, [...] , but not necessarily, ...
14
votes
1answer
2k views

Evolutionarily, why do male rats and horses lack nipples?

Developmentally male rats don't have nipples because (reddit) Testosterone release in the fetal male rat happens before the stage of mammogenesis where the teat is formed whereas other species ...
14
votes
2answers
487 views

Have we ever observed two drosophila lineages that evolved reproductive isolation in labs?

Background The standard definition of species refers to the concept of reproductive isolation. If two lineages are found to be reproductively isolated, then we consider these two lineages to belong ...
12
votes
1answer
781 views

If dinosaurs could have feathers, would they still be reptiles?

I just finished watching a video where it was mentioned that nowadays birds are dinosaurs and non-avians dinosaurs could have feathers. I confirmed this from wikipedia: Birds are highly advanced ...
0
votes
2answers
9k views

Will I grow taller? How can i tell? [closed]

I'm 17 and I'm about 160 cm and my weight is 47 kg . I just want to know if I will still grow taller ?
88
votes
5answers
11k views

Does DNA have the equivalent of IF-statements, WHILE loops, or function calls? How about GOTO?

Does DNA have anything like IF-statements, GOTO-jumps, or WHILE loops? In software development, these constructs have the following functions: IF-statements: An IF statement executes the code in a ...
53
votes
3answers
11k views

How does the brain's energy consumption depend on mental activity?

What is the impact of mental activity on the energy consumption of the human brain? I am most interested in intellectually demanding tasks (e.g., chess matches, solving a puzzle, taking a difficult ...
56
votes
4answers
46k views

Death because of distilled water consumption

One of my friends said that I would die if I drank distilled water (we were using it in a chemistry experiment) I gave it a go and surprisingly did not die. I did a bit of Googling and found this ...
24
votes
4answers
2k views

How and where, in the human brain, are memories stored?

Background I am a computer programmer who is fascinated by artificial intelligence and artificial neural networks, and I am becoming more curious about how biological neural networks work. Context ...
24
votes
3answers
2k views

Is it necessary to conduct a power analysis before beginning an experiment?

I know that power analysis is the statistically valid way to ensure you use the correct numer of samples or repeats in an experiment. But I have never seen any biologist actually conduct a power ...
23
votes
3answers
3k views

Which organism has the smallest genome length?

Which animal/plant/anything has smallest length genome?
5
votes
2answers
229 views

What to look for when buying a light microscope?

I am a science lover and want to buy a microscope to explore things around me. Like studying cell structures, microorganisms, blood and plants. It would be great if there is way to photograph slides. ...
44
votes
4answers
2k views

Why do men have nipples?

I'd be tempted to call nipples in men vestigial, but that suggests they have no modern function. They do have a function, of course, but only in women. So why do men (and all male mammals) have them? ...
13
votes
2answers
603 views

Evolution in 37 years, is it possible?

I am confused, can evolution ( speciation ) really occur in such a short time ? In 1971, biologists moved five adult pairs of Italian wall lizards from their home island of Pod Kopiste, in the ...
5
votes
3answers
749 views

A free book/resource for learning genetics?

I took an undergrad class in genetics. I felt it was not too intensive and I do not feel prepared for grad school (if I can manage to get in.) Does anyone know of a preferably free resource for ...
4
votes
1answer
3k views

Why are men stronger than women?

What are the evolutionary explanations for why women are physically weaker than men (on average), and is this difference adaptive? See figure one here. I suppose that something puts pressure on men ...
34
votes
1answer
1k views

What is itching?

What exactly at the molecular level is itching? What physiological function does itching serve, if any? I cant remember the reference but a PLCb3 null mice lost the itch phenotype, so presumably it is ...
9
votes
3answers
7k views

What makes a gene dominant or recessive [duplicate]

We all carry two copies of each gene (outside of male sex chromosomes). If the two differ from each other often one is dominant and one recessive. How does this mechanism work on a molecular level? ...
29
votes
2answers
7k views

What is the advantage of circular DNA in bacteria?

From what I understand, bacteria have circular DNA. What advantages does it have over linear strands like for eukaryotes? Do there exist bacteria with more than one ring of DNA?
14
votes
3answers
3k views

What implications has the missing 2'-OH on the capability of DNA to form 3D structures?

The chemical difference between RNA and DNA is the missing 2'-hydroxyl group in the nucleotides that build DNA. The major effect of that change that I know of is the higher stability of DNA compared ...
13
votes
1answer
863 views

The Origin of Mitochondria

For a long time I've just accepted, because it is just what everyone told me, that mitochondria became organelles in the cell when they were "engulfed" by another cell which acted like it's host. This ...
13
votes
4answers
50k views

What is the armpit hair for?

Modern human beings, especially women, cut their armpit hair. It seems to me the armpit hair is trivial/useless. Shortly speaking, what is the armpit hair for?
9
votes
3answers
8k views

Why doesn't recombination occur in male Drosophila?

"Males do not show meiotic recombination, facilitating genetic studies." For a while I have known that this phenomenon occurs, this quote comes from the Wikipedia page on Drosophila melanogaster, ...
7
votes
2answers
312 views

How does Natural Selection shape Genetic Variation?

Background Importance of the additive genetic variance As stated here, the fundamental theorem of Natural Selection (NS) by Fisher says: The rate of increase in the mean fitness of any organism ...
6
votes
1answer
1k views

What gives things their colour?

My 6 year old daughter asked me 2 biology-related questions yesterday and I tried my best to answer them with the aid of YouTube videos. One of the questions (I may post the other one too) was ...
6
votes
2answers
2k views

Why do DNA and RNA have the functions they have?

I know that there are two most important directions of genetic information transfer in living organisms: DNA->DNA and DNA->RNA. The first is replication, and the second is transcription. I wonder if ...
0
votes
3answers
1k views

How does the modern theory of evolution solve these apparent problems? [closed]

I hold to the truth of Evolution, but I've encountered several problems with it, that I can't answer, and I can't find an answer for, despite much research. If would be great if anyone can answer ...
28
votes
1answer
2k views

How long will a vegetable live for after being harvested?

I understand this might depend on the types of vegetables, but is there an average or studied specifics? Does it die immediately? Is there a way to precisely diagnose death in plants? If so, what are ...
19
votes
4answers
5k views

Why do parasites sometimes kill their hosts?

It's bothered me for a while now. I understand why a parasitoid would do this, as it only temporarily requires the host, and that not all parasites kill their hosts. There seems to be no evolutionary ...
16
votes
6answers
3k views

Why would a single celled organism evolve to be multi-celled?

I read a story this week on Richard Lenski who has been 'evolving' E. coli for more than 50,000 generations now. One comment I read was from someone who doesn't accept Evolution who pointed out that ...
15
votes
3answers
5k views

Are there any motile plants?

There are numerous examples of sessile animals (sponges, barnacles etc.) but are there any examples of motile plants? If not, why not? Surely mobility would have conferred an evolutionary advantage to ...
11
votes
1answer
382 views

What elements are a possible basis for life?

I've been told that life on earth is carbon-based, Then I got curious about one thing: What are the possible bases for life and under which circumstances could lifr based on other elements exist? If ...
9
votes
3answers
511 views

Genetic Diversity and Adaptation

I am somewhat new to evolutionary biology, having studied it on my free time as a computer science student. There is one particular thing that has always bothered me for which I have not seen a good ...
8
votes
2answers
445 views

Why do we have more male infant born?

For every 104 male babies,we have 100 female babies and there is a Statistics which is more reliable (we have 997 female infant born per 1000 male infant born). what's the reason? why do we have male ...
8
votes
3answers
1k views

Is there any kind of immortality in plants?

I asked a question about immortality of hydra and learned good things about senescence. Now I would like to know about immortality in plants, if there is some kind of immortality in plants and how ...
5
votes
1answer
567 views

How do sharks and other fish conserve and gain water in marine environments?

With the osmolarity of the average vertebrate being around 300mOsml, and salt water having an osmolarity of 1000mOsml, why does the water from the shark not leave to the salt water around it? I ...
4
votes
3answers
2k views

Polymorphism in cnidarians?

To me, the phenomenon of polymorphism in cnidarians is particularly troubling. I gather that it essentially refers to existence of various different forms or kinds of individuals, i.e. zooids and ...
3
votes
2answers
337 views

Changing the definition of life?

Viruses at this period of time do not fit the current definition of life. Much of the reasoning behind this is that we currently believe that all life must be made up of cells. Also, many ...
2
votes
2answers
161 views

building intelligent structure with random evolution requires series of non useful steps

In order to build an intelligent design such as a bridge or a mechanical watch, you need a series of non useful steps. As far as I understand, in random evolution theory, the "intelligence" involved ...
10
votes
1answer
238 views

Seeing strange things in light

I have noticed that if you look directly at tubelight (I have only white ones in my home) and close your eyes little, you see little random shaped colourless things sometimes with slow speed and ...

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