7
votes
1answer
222 views

What evolutionary advantages are provided by ovoviviparity?

I read that some sharks are ovoviviparous. What advantages and disadvantages are provided by this type of reproduction as opposed to egg laying and live birth?
14
votes
2answers
2k views

Why I have to pee more often in low temperature? [closed]

I realised that I have to pee more often in winter or simply the temperature is low. Is there any scientific explanation, or just simply psychology?
1
vote
0answers
132 views

First documented beneficial mutation?

I've been reading up on beneficial mutations, and am curious when we discovered and documented the first one. Can anyone point me to the first documented beneficial mutation? Per request, let me ...
5
votes
3answers
223 views

How does menstruation proceed during one period?

I'm simplifying things here: A. Does a woman bleed constantly, like a drop every 10 minutes? Two hours without pad or tampon and your underwear is dirty? or B. Does a woman bleed suddenly a ...
4
votes
1answer
180 views

How does Pothos grow in only water?

The popular potted plant, Pothos aureus (or Epipremnum aureum) is happy to grow in a jar, with only water, for years. How is this possible when other plants need at least Nitrogen, Phosphorus and ...
9
votes
1answer
2k views

What senses are active while sleeping?

During sleep, our body activity decreases. I am wondering on the extent of the lowering of this activity regarding our five senses. Clearly, the sense of touch is still very efficient since shaking a ...
10
votes
3answers
1k views

Why did humans become bipedal?

Somewhere in evolutionary history homo started walking upright and became bipedal. You hear these hypotheses that, by walking upright, they could see better across the grassy savannas to escape ...
3
votes
0answers
65 views

Is there a standard formula/calculation for sexual dimorphism?

Is there a standard, or most accepted, way to present a value for sexual dimorphism? For example, one could use $$\frac{\text{Female value}}{\text{Male value}} -1$$ This would give negative values ...
1
vote
1answer
60 views
2
votes
2answers
3k views

Blood circulation - How to expand blood capillaries?

Do blood capillaries expand? If yes, through what means can it be done? And can warm water also be used to expand blood capillaries?
0
votes
0answers
52 views

Phenotype choice for one of a MZ twin pair in a genetic association study

I was having a discussion with a colleague and this question came up... It is commonplace in molecular genetics studies to only genotype one of a pair of monozygotic twins (and then implicitly impute ...
9
votes
3answers
6k 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? ...
1
vote
1answer
61 views

Was Earth's atmosphere more buoyant in the prehistoric era then today?

The mass and size of the dinosaurs and prehistoric insects continues to amaze me. I read from an earlier post that oxygen was more abundant during the prehistoric era. However supporting the weight ...
3
votes
0answers
51 views

How does beta branching stop alpha helices from forming?

I am told that beta branching interferes with alpha helix formation. Problem is that I don't see how beta branching has anything to do with alpha-helix formation. Beta-branches are on the outside of ...
17
votes
3answers
48k views

Why can white hairs get dark again?

I have learned (probably in high school?) that hairs turning white is caused by the part of the folicle which produces the pigment dying and being replaced by an air bubble. This sounds very ...
2
votes
0answers
43 views

How to get a pdb file of a single atom?

I am trying to get a pdb file that contains a single atom, it doesn't matter if it's Hydrogen or another atom. How can I obtain this? Are there any pdb files with just a single atom available to ...
2
votes
2answers
161 views

Agony, Hydrophobia and viruses in the light of evolutionary principles

I'm undergraduate physics student, but I've always been interested in biology. So I have a couple of questions about an application of the evolutionary principles to practice. Agony as the last ...
4
votes
1answer
40 views

How to measure heat loss in Tardigrades

I want to measure metabolism in tardigrades (a jar of 30 tardigrades). I know that an easy way to measure metabolism is heat loss; I can just measure the temperature of the water before and after a ...
3
votes
1answer
111 views

What fish (and/or shellfish) species with a multi-year life-cycle, besides salmon, die after spawning?

Most species of salmon die after spawning. Are there any other types of fish that spawn once and then die after a multi-year life-cylce? Is this a rare life history strategy among our human exploited ...
3
votes
1answer
76 views

List of dinosaurs synonyms

Is there a comprehensive list of dinosaurs synonyms with indications of which name is now considered correct? Something like "there's no brontosaurus, there's only Apatosaurus", "there's no ...
2
votes
1answer
561 views

Thermodynamics of Forming Peptide Bonds

Which of the following shows the correct changes in thermodynamic properties for a chemical reaction in which amino acids are linked to form a protein? A) +ΔH, +ΔS, +ΔG B) +ΔH, -ΔS, -ΔG C) ...
2
votes
2answers
139 views

How to retrieve full gene names list and Entrez gene IDs and other annotation information from HUGO gene name list (in R or any)?

How to retrieve full gene names and Entrez gene IDs and other annotation information from HUGO gene name list (in R or any other software or language)? Is it possible vice versa: having full gene ...
25
votes
7answers
5k views

Is there anything that is completely non-toxic to humans at any dose?

Lately I have seen a number of unrelated "scientific" debates over whether certain substances should be outlawed because they are toxic to humans. My initial, informal reaction is usually to respond ...
12
votes
1answer
236 views

Why are fly not scared when landing on a monitor with changing graphics?

I have been wondering why would insects in general, not be scared when important changes happen on your monitor where they have landed... If you move even just a finger, they are scared to death and ...
3
votes
1answer
53 views

How does Trifluralin kill newly germinating seeds, with almost no effects on established ones?

Trifluralin (2,6-Dinitro-N,N-dipropyl-4-(trifluoromethyl)aniline) is a pre-emergent herbicide used in landscape beds before the application of mulch (my use for it, anyway). It kills the weeds as they ...
10
votes
2answers
292 views

Can canines communicate with each other using gaze direction?

After researching why humans have white scleras when most primates have dark scleras, I stumbled upon the cooperative eye hypothesis. It proposed that white scleras may have evolved on behalf that it ...
3
votes
1answer
82 views

Heart Rate being normal when under treatment for the bends

When you surface from diving too quickly; you get "bends" - these are caused by gas bubbles forming in your lungs (especially nitrogen). This causes breathing problems if not treated since the bubbles ...
3
votes
1answer
100 views

Are abrasions considered closed wounds?

A closed wound is one where skin is intact and underlying tissue is not exposed to the environment. Abrasion is an erosion of skin usually due to sheering force. In most cases the dermis is intact ...
1
vote
1answer
52 views

Alternative plant taxonomies to Linneaus

In addition to Linneaus-inspired taxonomies of the botanical world, I suppose there are some other proposals for different kinds of taxonomic accounts, perhaps for specific sub-domains of botany or ...
1
vote
0answers
51 views

Do Parasaurolophus have hands with fingers to grab?

http://en.wikipedia.org/wiki/Parasaurolophus#mediaviewer/File:Parasaurolophus_cyrtocristatus.jpg I cannot tell if the hands have fingers strung together to form a hove, or fingers to grab. I have ...
6
votes
0answers
114 views

Up to date, extensive documentary about dinosaurs?

I just finished reading the Wikipedia page about dinosaurs, and I very much enjoyed it. I knew that much of what I learned in the 80's as a child is (and was) incorrect, and now that I am a parent, I ...
2
votes
1answer
32 views

How does Isoxaben kill newly germinating seeds, with almost no effects on established ones?

Isoxaben (N-[3-(1-ethyl-1-methylpropyl)-1,2-oxazol-5-yl]-2,6-dimethoxybenzamide) is a pre-emergent herbicide used in landscape beds before the application of mulch (my use for it, anyway). It kills ...
6
votes
1answer
74 views

Why doesn't Fenoxaprop-P-ethyl damage cool season lawns?

For controlling bermudagrass, Cynodon dactylon, a serious perennial grassy lawn weed in my area, I use the herbicide Fenoxaprop-P-ethyl. It kills the bermudagrass rather well, without damaging the ...
-1
votes
3answers
713 views

Why scientific names of animals & plants are made difficult to spell & remember?

Why scientific names of animals & plants are made difficult to spell & remember? Mango: it is easy to spell. Corvus splendens: it is difficult to spell
0
votes
0answers
22 views

Polychromatic Fur considered against Monochromatic Hair

As I was gazing at a strand of fur that had shed from my cat, I was struck by the alternating bands of white, black, and tan. It seems that genetically coding for such an intricate coat pattern would ...
2
votes
1answer
203 views

Does increased cell turnover cause cancerous mutations?

If a certain set of cells or tissue are undergoing a lot of reproduction and repair cycles for some reason, does this inevitably lead to cancerous growths? If the mutation rate exceeds the normal ...
9
votes
1answer
67 views

Why doesn't Clopyralid damage cool season lawn grasses?

I use Clopyralid (3,6-dichloro-2-pyridinecarboxilic acid) to kill broad leaved weeds in lawns. From my understanding, it works by mimicking an auxin which affects plant growth. Naturally this pulls ...
2
votes
0answers
77 views

Why did animals evolve genders? [duplicate]

The majority of animals have two genders, and both are needed in reproduction. It seems like it would be more advantageous for creatures to be hermaphrodites, since they could mate with any member of ...
4
votes
2answers
322 views

Why White Blood Cells (WBCs) do not react to foreign bodies like sperm?

Why do the white blood cells allow foreign bodies like sperm to exist inside body cavity without any reaction? White blood cells function is to fight against foreign bodies (from the text books).
3
votes
1answer
565 views

Why are sperm cells not attacked by the female immune system? [duplicate]

Whenever a foreign particle enters into someone's body, it is attacked by the white blood cells. I just want how it is that, when sperms enter the female body, they are not attacked by the the woman's ...
8
votes
2answers
2k views

Why don't breast enlargements leave any marks of surgery on breasts?

If we get stitches, we get marks left on the skin, but there are no marks for breast enlargements. I saw a YouTube video about a breast enlargement wherein a doctor makes a cut. Where does the cut ...
8
votes
1answer
142 views

How does Halosulfuron-methyl kill nutsedge, while leaving lawn grass and most weeds undamaged?

I use Halosulfuron-methyl to control yellow and purple nutsedge in lawns. This chemical acts by interfering with the acetolactate synthase enzyme, which quickly slows cell division, and growth at all ...
1
vote
0answers
149 views

Why not use lactase to aid the break down of lactose when making biofuels?

I did an experiment using nine different substrates (Lactose + lactase, corn, sugar cane, glucose control, wood, grass, no yeast control and yeast control) and observed their fermentation rates. ...
5
votes
2answers
4k views

Diffusion of Hypotonic solution into solution with glucose and starch

Cell walls are selectively permeable to ions and organic molecules. Sometimes the selectivity is passive and a reflection of the physical laws governing diffusion. We can do simple experiments that ...
3
votes
2answers
143 views

Would a plant need light if the chemicals gained by photosynthesis were given through the roots or as a foliar spray?

If you took the chemicals a plant gains through photosynthesis and put it through the plants' roots or by injection, or used as a foliar application for intake through the stomata, would the plant ...
6
votes
0answers
70 views

How to measure Na/K channel activation at the membrane level?

Assume that there are two different signals occurring on the ECG - during depolarization and repolarization in the standard ECG. I was advised not to use the standard ECG in measuring the exact ...
2
votes
1answer
75 views

Are alleles passed down and shuffled randomly to the offspring during meiosis or fertilization?

If it does occur during meiosis, are the alleles switched over from one sister chromatid to the other during the crossing over process in Prophase I?
3
votes
1answer
27 views

How long do zebra fishes remain transparent?

As larva, zebra fishes are transparent, at least up to 5-6 days. I wonder what would be the upper limit of the transparent period. This is of relevance considering purposes for imaging. The question ...
8
votes
0answers
93 views

How to define “Quasifixation” in continuous approximation of finite population?

Background Many models including the famous very first models derived by Sir Ronald Fisher in his early career, assume infinite population size. In an infinite population, an allele can rise in ...
1
vote
0answers
52 views

Cannot conjugate Biotin-labeled DNA to Streptavidin-labeled solid surface

I have been trying to immobilize DNA by the bioconjugation of biotin and streptavidin, but I cannot get this work. I added EDC and streptavidin to COOH ...

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