活胚胎始終朝著溫暖點移動，卻避開了危險的過熱溫度點,。圖片來源：《科學(xué)》
冷血動物一生都在它們的棲息地中走來走去,，像喜光的金鳳花一樣尋找完美的溫度。但若它們生存于一只蛋中會發(fā)生什么呢,？
科學(xué)家之前曾觀察到甲魚胚胎會朝其蛋中的溫暖點移動,，但他們并不能解釋該運動是有意的還是被動的,、是否由流體動力學(xué)所驅(qū)使。因此一隊研究人員決定進行實驗,。他們在不同的溫度下孵化了125只中華草龜?shù)?，并在蛋中?chuàng)造過熱、過冷和正好的溫度點,。圖中的活胚胎始終朝著溫暖點移動,，卻避開了危險的過熱溫度點。研究人員日前將報告在線發(fā)表于《生物學(xué)通訊》上,。
同時,，死亡胚胎一點都沒有移動，說明活胚胎的活動是有一定的意向性的,。由于孵化溫度的輕微差別會決定烏龜?shù)男詣e,，因此胚胎本身可能對將其變成雄性草龜還是雌性草龜有一定的控制力。（生物谷Bioon.com）
生物谷推薦英文摘要：
Biology letters Doi: 10.1098/rsbl.2013.0337
Turtle embryos move to optimal thermal environments within the egg
Bo Zhao1,2, Teng Li1, Richard Shine3 and Wei-Guo Du
A recent study demonstrated that the embryos of soft-shelled turtles can reposition themselves within their eggs to exploit locally warm conditions. In this paper, we ask whether turtle embryos actively seek out optimal thermal environments for their development, as do post-hatching individuals. Specifically, (i) do reptile embryos move away from dangerously high temperatures as well as towards warm temperatures? and (ii) is such embryonic movement due to active thermoregulation, or (more simply) to passive embryonic repositioning caused by local heat-induced changes in viscosity of fluids within the egg? Our experiments with an emydid turtle (Chinemys reevesii) show that embryos avoid dangerously high temperatures by moving to cooler regions of the egg. The repositioning of embryos is an active rather than passive process: live embryos move towards a heat source, whereas dead ones do not. Overall, our results suggest that behavioural thermoregulation by turtle embryos is genuinely analogous to the thermoregulatory behaviour exhibited by post-hatching ectotherms.
