Before each of their revelations many thinkers at the time had sustained more ancient ways of thinking, including the geocentric view that the Earth was a the centre of our universe.
Before each of their revelations many thinkers at the time had sustained more ancient ways of thinking, including the geocentric view that the Earth was a the centre of our universe.
某版本高中生物学教材中,“生长素的发现过程”的部分内容如下。
生长素的发现过程
19世纪末,达尔文(C.Darwin,1809—1882)注意到了植物的向光性,并设计了实验来探究其中的原因。
实验发现,在受到单侧光照射时,金丝雀虉(音yì,—种禾本科植物)草的胚芽鞘会向光弯曲生长;如果去掉胚芽鞘的尖端,或者用锡箔罩子把尖端罩上,则不发生弯曲;如果罩上尖端下面的一段,那么,胚芽鞘还会弯向光源生长。
达尔文根据实验提出,胚芽鞘尖端在受单侧光刺激后,就向下面的伸长区传递某种“影响”(influence),造成伸长区背光面比向光面生长快,因而使得胚芽鞘出现向光性弯曲。
要求:
(1)根据上述材料设计并绘制达尔文的实验示意图。(10分)
(2)设计使用上述示意图的教学过程。(20分)