36 votes
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Why is a mosquito feeding on human blood not a parasite?

A mosquito is a biological parasite, it is not a medical parasite. There are two definitions of parasite. A biological/ecological definition and a medical/physiological interaction definition. A ...
John's user avatar
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35 votes
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Why do animal cells "mistake" rubidium ions for potassium ions?

There are multiple biological mechanisms that can be brought to bear for distinguishing between atoms. In addition to binding properties (e.g., ionic charge, electronegativity, bond strength), there ...
jakebeal's user avatar
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32 votes
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Why do both the mango and the bee have "Indica" in their binomial name?

In short, we do not think about the uniqueness of the second part of the binomial (the species epithet) but about the uniqueness of the binomial itself (the genus and the species epithet). Thus, the ...
NatWH's user avatar
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24 votes
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ECG wave names origin

Interesting question! I searched briefly and came up with an answer from this short paper. I won't repeat all the details of the paper, but to be not a completely link-only answer I will give a brief ...
Bryan Krause's user avatar
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24 votes

Does the cytoplasm include the organelles?

The cytoplasm is like the ocean. When you talk about the ocean, do you include the fish? What about islands? Sometimes yes, sometimes no. You could use a cytosol/cytoplasm distinction, where cytosol ...
Bryan Krause's user avatar
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23 votes
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Explaining "paraphyly" for the layperson?

These are terms to describe names we give things that don't really follow phylogeny accurately. Fish, for example - a monophyletic group involving fish would include humans, too, yet there are many ...
Bryan Krause's user avatar
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21 votes
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What is the anatomical term for a two jointed leg?

Welcome to Biology.SE! I think you are talking about plantigrade, digitigrade and unguligrade. Please note that the number of joints in mammals does NOT vary, but only the relative length (and shape)...
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21 votes
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What does rescue mean in the context of biological experiments?

"Rescue" in an experimental context means you're capable of undoing some experimental manipulation. It's considered evidence towards identifying a causal mechanism or verifying that your ...
Bryan Krause's user avatar
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20 votes

Is a walnut a nut or a drupe?

Short answer Walnuts are classified both as nuts and drupes ('stone fruits'). background According to University of Wisconsin - Madison, Department of Botany , hickory and walnut can be classified ...
AliceD's user avatar
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19 votes

Is a DNA molecule a single strand of polynucleotide or two of them linked together?

Hmm, I think that the teacher is actually correct and that the previous explanation, although very nicely referring to text book diagrams, is a little misleading. The issue here is the nature of a ...
Dr Newman's user avatar
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18 votes

Does the cytoplasm include the organelles?

The young scientist asks: “What is the correct definition?”. The old scientist answers: “As is often the case in biology, there is no correct definition — different people adopt different usages.” ...
David's user avatar
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16 votes
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What is the difference between "Bisphosphate" and "Diphosphate" in biochemistry?

[Source:Wikipedia] As you can see in the above structure of ADP(Adenosine di-phosphate), the two phosphate groups in the compound are directly attached to one another. So it is named as di-phosphate. ...
Mesentery's user avatar
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14 votes
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Using anatomical terms for human organs and parts of plants

First, for reference, see here for a discussion about the difference in directional terms between bipeds and quadrupeds as well as a fairly complete explanation of word meanings/etymology. The ...
theforestecologist's user avatar
14 votes
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What is the difference between cytosol and cytoplasm?

IMO, the definitive answer to this question is given in a paper by J. S Clegg. He traced the origin of the term cytosol to a book chapter by H. A. Lardy, and confirmed by email that Lardy had indeed ...
user338907's user avatar
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14 votes
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What is the difference between a protein and a factor?

TLDR: As far as I know, there's no specific reason some proteins are called "factors"; it's just a matter of what name was chosen. "Protein" is a specific term meaning a long chain of amino acids. ...
Jam's user avatar
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14 votes
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What is the definition of "Natural Selection"?

Official definition Is there an official definition of natural selection that is adopted by biologists nowadays? and what is that definition exactly? I don't think there is such a concept as an "...
Remi.b's user avatar
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14 votes

Explaining "paraphyly" for the layperson?

One very simple example that most people are familiar with is the vernacular use of "animal". Most people recognize that humans are animals and more closely related to other animals than ...
WaterMolecule's user avatar
13 votes

Are all carcinogens mutagens?

How can a non-mutagenic agent be carcinogenic? An agent that causes overexpression of oncogenes or inhibition of tumor suppressors, would be carcinogenic but not mutagenic. HPV, for instance, produces ...
WYSIWYG's user avatar
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13 votes
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How to decipher references in natural history works of the late Renaissance and early Modernity?

I have found what may be the holy grail. It is a book known as "A Botanical Materia Medica" by Jonathan Stokes. This has several volumes, but the one you want is volume 1, which has no ...
bob1's user avatar
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12 votes

Is a walnut a nut or a drupe?

A true nut, botanically speaking, is a hard-shelled pod that contains both the fruit and seed of the plant, where the fruit does not open to release the seed to the world. Some examples of ...
wanderweeer's user avatar
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12 votes
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What is the meaning of multicellularity?

Bacteria are, as a general rule, unicellular. However, there are some, like the cyanobacteria which you referenced, which are kind of border line. Wikipedia's definition of multicellularity is a ...
rotaredom's user avatar
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12 votes

What is the difference between a protein and a factor?

Short Answer There is no agreed upon naming convention for proteins - there are some rough standards because in language people usually try to convey their ideas in a way others can understand, but ...
Bryan Krause's user avatar
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12 votes

Why do both the mango and the bee have "Indica" in their binomial name?

That is the species name it is often the same for unrelated organisms, that is why we use a two name system. Binomial nomenclature (literally, two term naming system) goes Genus species respectively. ...
John's user avatar
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12 votes
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What is a synonym of the word design that can be used in context of evolution?

Although not ideal, "adaptation" is more appropriate than "design" as a noun describing something that has come about in an evolutionary context, even though not all evolution is adaptive. In writing,...
Bryan Krause's user avatar
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12 votes

Are all carcinogens mutagens?

Alcohol itself is non-mutagenic because it does not directly alter DNA. (Additionally ethanol enhances carcinogenesis and is itself not a carcinogen - updated) There are similar non-mutagenic ...
Asad Yamin's user avatar
11 votes
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Was Darwin aware of the difficulties behind the concept of species?

The whole point of Darwin's theory was that transition from one species to another is extremely slow and gradual. There are plenty of quotes in "Origin of Species" stating this, and also affirming ...
IMil's user avatar
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11 votes
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Dorsal vs Posterior and Ventral vs Anterior

Short Answer This page on wikipedia gives a good synopsis of these concepts. The confusion lies in the fact that many websites on anatomy discuss/describe/define these terms in relation to humans. ...
theforestecologist's user avatar

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