Questions looking for clarifications or definitions of biological terminology.

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18 views

How is death of a tree defined?

When a human's brain is dead and the heart stops beating, he is generally considered as dead. Such definition can be made because human has a centralized coordination system and a critical organ that ...
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1answer
60 views

What are the characteristics of a living organism? [closed]

It seemed fairly basic at first, and yet I have to ask because even a quick Google search reveals that it doesn't seem to be quite so straight-forward anymore. After more research, I found multiple ...
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2answers
53 views

Is there a formal definition of `nature` in Biology?

I've been discussing with a friend about Earth Day and at a certain point came out the question What do you call "nature"? He said that he considers "nature" basically all matter, including ...
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1answer
216 views

Was Darwin aware of the difficulties behind the concept of species?

Introduction The concept of species is a very old concept that suffers from not being a natural category. There exists no single definition that would categorize living beings into groups and that ...
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3answers
20k views

Do apes and humans share 99% of DNA or 99% of genes? What is the difference?

I made an answer on the Scifi.SE that can be read here. It is about how the characters in the story Jurassic Park might have gotten DNA for all the species shown. In my answer, I said this: Apes ...
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1answer
189 views

What does pseudo-irreversible mean?

In this publication (PDF) I encountered the following word: Binding of rupatadine to histamine H1 receptors isolated from the guinea-pig cerebellum and lung was demonstrated by inhibition of ...
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2answers
78 views

What is the definition of a mutation?

There are two alleles that determine the sensitivity of a person to Coumadin (a medicine for blood thinners used to treat a stroke etc). Sometimes you encounter the terminology that one has a mutation ...
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1answer
26 views

What would be “Sternum-Intermediate” distance?

I've asked this question on the English Language & Usage board, not being entirely sure whether this question is strictly medical, or just English knowledge suffices to answer. Do note I am no ...
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1answer
149 views

What is a tardigrade “in tun form”?

While reading this article about tardigrades that had been previously frozen, I came across some verbiage I wasn't sure of and couldn't find any real explanation given the context. The article kept ...
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2answers
49 views

What is the definition for vitamins?

I have found the following definition on Wikipedia: An organic chemical compound (or related set of compounds) is called a vitamin when the organism cannot synthesize the compound in sufficient ...
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2answers
6k views

Is blood an organ according to biology?

It consist approximately 7 percent of body weight. By definition organ is composed of multiple tissues. Blood is a fluid, a circulating tissue. Therefore can we call this fluid system a liquid organ?...
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0answers
39 views

“Signal Advance”: Unsure of meaning or contextual use

I am reading through Recombinant DNA; Genes and Genomes - A Short Course - Third Edition by James D. Watson, et. al. and I came across this paragraph in the discussion about discrete factors of ...
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2answers
1k views

What is an organism?

The definition of an organism Wikipedia gives is An organism is any contiguous living system. I understand that these are not organisms according to this definition: A bird and a tree it's ...
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2answers
435 views

Transitivity of Species Definitions

There are many definitions of "species" which usually take the form Two individuals are of the same species if ... An implied (rarely made explicit) property of any sensible species definition ...
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2answers
3k views

Are spiders part of the study of entomology?

The definition of entomology says it is the science of studying insects. I know spiders are not insects but does entomology include studying spiders as well? Otherwise is there any name to the ...
2
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1answer
50 views

How do we call a region of low carrying capacity?

I am looking for a convenient word to define a region of the landscape where the local carrying capacity (population size) for a given species is low but different from zero. The species is still ...
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1answer
198 views

Definitions of common and rare disease

Is there an epidimiological way to define rare and common diseases ?
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1answer
52 views

Can a relationship exist that is mutualistic/parasitic/etc. but not considered symbiotic?

Wikipedia definition of symbiosis: "Symbiosis (from Greek σύν "together" and βίωσις "living")[2] is close and often long-term interaction between two or more different biological species." Wikipedia ...
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2answers
161 views

Definitions of robustness and canalization

The concepts of robustness and canalization are fashionable today in the biology literature. However, I am not sure of their definitions and I am not sure either that all authors actually use the same ...
5
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1answer
5k views

What is the definition of a stringent/relaxed plasmid?

I have found a publication which proposes some definitions, including a definition for strict and relaxed replication. The definitions are: Relaxed control of plasmid replication. Relaxed control ...
5
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2answers
214 views

What is Environmental Robustness? Is it different from plasticity?

Hansen (2006) in his review uses the concept of environmental robustness independently of the other concepts of robustness (at pages 139 and 140) without defining ...
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1answer
339 views

What does “Mutational Variance” mean?

Background The concept of mutational variance can be found in many articles including this one for example. The mutational variance of a trait number $i$ can be found in the M-matrix in position $m_{...
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1answer
1k views

Soft and Hard selection

Seems to me that these two sources (M. Whitlock, B. Wallace) use different definitions of soft and hard selection. M. Whitlock: Soft selection occurs when the relative fitness of an individual is ...
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1answer
73 views

What is a sex-biased gene?

How do you define a male-biased gene and a female-biased gene as they are found in the abstract of this article.
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1answer
231 views

Definition of Sexual Selection?

How do you define Sexual Selection (SS)? (One might want to subdivide SS into intra- and inter- SS to answer) Is SS clearly different from Natural Selection (NS)? Is SS nested within NS or are NS ...
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1answer
896 views

What the difference between an inverted and everted retina?

I'm looking specifically for examples and comparisons, because the definitions of inverted and everted are remarkably similar; e.g. from Dictionary.com/Reference.com: everted verb (used with ...
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1answer
62 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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1answer
9k views

What is a suicide plasmid?

What is a suicide plasmid? Example: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2737453/ mentions a "suicide vector". See also http://www.sci.sdsu.edu/~smaloy/MicrobialGenetics/topics/plasmids/allele-...
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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 ...
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1answer
3k views

What is the definition of “dry weight” and “dry cell weight”?

As I understand it, the dry weight of something is its weight minus the weight of its water content. Is this the definition? What about dry cell weight?
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0answers
270 views

On the definition of gDCW (gram dry cell weight)

I need some clarification on the concept of gram dry cell weight. The unit acronym gDCW stands for gram dry cell weight. My interpretation is that 1 gDCW is equivalent to 1 gram of dry cells, but I ...
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1answer
804 views

What is an on-line measurement? What is an off-line measurement?

See it used here: http://en.wikipedia.org/wiki/Fed-batch. In the table giving the different strategies to control growth in a fed-batch culture, one finds, for example: "on-line measurement of glucose"...
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2answers
2k views

What is a cortical circuit?

I have read about cortical circuits in the context of connectomics (e.g. any example here) and computational neuroscience (e.g. any example here), but a simple Google/Wikipedia does search not show an ...
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1answer
888 views

What is the difference between abiogenesis and spontaneous generation?

As we all should know, abiogenesis and spontaneous generation are far from identical. For one, spontaneous generation was disproven with Pasteur, and abiogenesis seems to be a solid scientific theory. ...
7
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1answer
73 views

Can an organism obtaining a part of its genome via horizontal gene transfer be called a “hybrid”?

Wikipedia definition of "hybrid" offers many competing definitions. But most seem to be centered on sexual-reproduction gene transfer. Is there an official (in a textbook or widely accepted peer ...
4
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1answer
114 views

How would one describe the R-factor in crystallography?

Yes, there is the wikipedia definition, but how would one explain this concept to a non structural biologist?