Green world教案
t:(after some minutes’ discussion.)now give us your answers,please.who will answer the first question?
sf:he found 13 kinds of findes,related to each other in the structure of their beaks,tails,shape of body and colour of their feathers.the most curious fact was the differences in the size of the beaks.this could only be explained from the differences in habitat and source of food.the birds with broad beaks would eat hard seeds,while the birds with smaller beaks would eat soft seeds or insects.
t:please give us the answers to the second question.
sg:he found that many characteristics were passed on from one generation to the next,without influence by the environment.
sh:i’ll answer the last question of part 1.he found evidence for the existence of stable varieties within species in nature.he showed that differences between plants of one species occurred as a result of the environmental conditions in their habitat.
si:i think,in part 2,for the first blank,we should fill in the words “of different” and the second,“of the same”.am i right?
t:what do you think,s j?
sj:i think he is right.
t:for the last question,what are your opinions?
sk:soil conditions are important to the output of crops.but that is one side of the question.the research by darwin,mendal and turesson shows that both genetics and the environment are important to plants.if we don’t have good seeds,good soil conditions are not enough for us to improve the output of the crops.am i right?
ss:we agree with you.
(teacher plays the tape after the students’ discussion.then teacher asks students to read the text aloud and find questions in the text.teacher gives brief explanation to them.)
step ⅴ summary and homework
t:now let’s think about a question:what can we learn from the text?(write it on the blackboard.)discuss it with your partner.(after a while.)who can tell us what you think?
s1:we should observe everything carefully and think deeply,then we can draw a good conclusion.
...
t:very good.now let’s see how the scientists observe and think.
(teacher writes observation,thinking,conclusion...on the bb.)
t:so much for the text.now today’s homework:
1.make sentences with the words and phrases:
whatever;lead sb. to do sth.;nowhere,variety;in view
2.do writing on page 35.
sample writing:
dandelions
in nature,there are varieties of environmental conditions for the plants to grow in.some places are hot and dry and there is little rain while in other places it is cool and wet.so the same plants that grow in different places are quite different.