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I need to read this article — "Beyond the rainbow" by Marie-Claire Koschowitz et al., for an exam.

Following are some questions for which I could not figure the answer out after reading.

1) Why does this miniaturization necessitates insulation ? Following is quote from article: "For fast-growing, presumably warm- blooded animals , such miniaturization would only have been possible with sufficient body insulation. "

2) Dinosaurs suppose to have tetrachromacy. The article mentions "dinosaurs were endowed with the highly differentiated color vision of birds". Does this mean Dinosaur's "inherited" their tetrachromacy from birds ? Why does the article mention reptiles before that ? Are birds reptiles ?

3) The article starts talking about how mammals develop fur and lost their highly differentiated color vision because they gave up structural color signaling. What is the direct connection between mammals and the dinosaurs ? I don't see the parallel here....why bring the mammals into the discussion ?

4) What is the connection between pennaceous feather and planar feathers ?

Any or all questions answered is welcome ! Thanks !

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closed as too broad by rg255, AMR, March Ho, kmm, fileunderwater Jan 30 '16 at 19:14

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

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    $\begingroup$ You cannot ask for an explanation of an article. A) It would be too broad B) Homework questions are considered off-topic unless you show an effort. It is fine to ask something that you do not understand from a paper but that has to be a precise point. And the article is in clear and understandable english. $\endgroup$ – WYSIWYG Dec 22 '14 at 5:39
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    $\begingroup$ could you provide an actual link? $\endgroup$ – shigeta Dec 22 '14 at 5:46
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    $\begingroup$ I think the question, although still broad (i.e., multiple questions) is eligible for re-opening. I have adapted my answer. $\endgroup$ – AliceD Dec 23 '14 at 4:18
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    $\begingroup$ you guys are too tough on newbies - asking for clearer question should be first resort. closing second. $\endgroup$ – shigeta Dec 23 '14 at 5:12
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    $\begingroup$ @JennaMaiz If you can then please ask some points as a new question. For example the vision part can be separated from the feather/fur part. Miniaturization can also be another question and there are some posts here related to that topic already; you may also have a look at those. I am voting for reopen but it would be nice if you narrow the question down. $\endgroup$ – WYSIWYG Dec 23 '14 at 6:01
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I will answer the questions one by one-

  • Why does this miniaturization necessitates insulation ? An organism's volume determines the total amount of heat that can be stored. The loss (exchange) of heat between the body and external environment mainly occurs on the skin's surface. Hence, body volume determines how much heat is stored, while body surface determines how fast that heat is dissipated to the environment. Volume increases with a power of three with radius, while surface increases with a power of two. Hence, smaller animals have large surface-to-volume ratios, which decreases rapidly with body size. Hence, small animals will dissipate relatively more heat per unit of time.

  • Dinosaurs suppose to have tetrachromacy. The article mentions "dinosaurs were endowed with the highly differentiated color vision of birds". Does this mean Dinosaur's "inherited" their tetrachromacy from birds ? No, birds are the closest living relatives to dinosaurs, and birds can be said to have inherited tetrachromacy from dinosaurs - see the cladogram below.

cladogram

  • Why does the article mention reptiles before that ? Are birds reptiles ? Birds are not reptiles, they are separate classes within the animal kingdom.

  • What is the direct connection between mammals and the dinosaurs ? ... why bring the mammals into the discussion ? Here below is another cladogram; there is no obvious, direct (evolutionary) connection between dinosaurs and mammals. The thing is that dinosaurs ruled the world before the last mass extinction, thereafter it were the mammals. That's why the authors discuss them both, I guess. Especially since we are mammals it may make sense to draw parallels.

mammals dinos

  • What is the connection between pennaceous feather and planar feathers As far as I could track the two down, they are the same (Prum, 2006)

Lastly, in response to your original question, before edits: Here is a link with a plain-English popular-scientific web article published online by the first author.

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