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Questions tagged [definitions]

Questions looking for clarifications or definitions of biological terminology.

18
votes
2answers
881 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 is ...
12
votes
3answers
1k 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 ...
22
votes
6answers
34k 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 ...
6
votes
3answers
4k 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 ...
15
votes
2answers
5k views

Are 'homeothermic' and 'endothermic' synonymous?

I got this question from the comments below this answer. So, do homeothermic and poikilothermic have the same meaning as endothermic and ectothermic, respectively? A user also suggested that the ...
4
votes
1answer
312 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 ...
3
votes
1answer
693 views

The meaning of the $\alpha$ helix and $\beta$ sheets in proteins [duplicate]

I asked this question to my Biology teacher and he, in collaboration with a Chemistry teacher, couldn't find the answer. My question is the following: "What does the $\alpha$ and $\beta$ represent in ...
1
vote
1answer
250 views

Usage of “lineage” over “species”

Remi.b has suggested here: The concept of species is poorly defined and is often misleading. The concept of lineage is much more helpful. IMO, the only usefulness of this poorly defined concept ...
1
vote
0answers
633 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 ...
3
votes
1answer
8k 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?
2
votes
2answers
399 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 ...