19,879
edits
Changes
→Key Stage 4
===Development of the Theory of Evolution===
====Creationism====
: Before a '''theory of evolution''' [[Christian]]s believed that all the [[species]] on [[Earth]] were created in their current form just 6000 years ago when the [[Earth]] was created by [[God]]. (They arrived at this number by adding up the ages of the descendants of [[Adam and Eve]] until [[Jesus]].
====Lamark's Theory of Evolution====
: In the early 19th century [[Jean-Baptiste Lamark]] developed a '''theory of evolution'''. However, he did not propose [[Natural Selection|natural selection]] as the cause.
: [[Jean Baptiste Lamark|Lamark]] believed that the behaviour and environment of an [[organism]] would cause it to change in its lifetime and those changes could be passed on to their [[offspring]].
: He suggested that the '''evolution''' of the [[giraffe]] was caused by many generations of [[giraffe]] stretching their necks to reach higher food. When a [[giraffe]] stretched its neck then the [[offspring]] would also have longer necks.
: [[Lamark]] believed that all [[species]] began as simple worms which would spontaneously appear and over time their behaviour and environment would change them and pass that change onto their offspring.
: [[Lamark]] was right that [[species]] '''evolve''' over generations, but wrong about the cause.
====Charles Darwin "On the Origin of Species"====
: [[Charles Darwin]] took [[Jean-Baptiste Lamark|Lamark]]'s '''theory of evolution''' and proposed a different cause.
: When visiting the [[Galapagos Islands]] [[Charles Darwin|Darwin]] noticed that on each [[island]] there were a group of [[bird]]s called [[Finches]] which has slightly different features on each [[island]].
: The environment on each [[island]] was slightly different and those features seemed to make the [[Finches]] perfectly suited to their own [[island]].
: [[Charles Darwin|Darwin]] proposed this was caused by [[Natural Selection]] which was based on three [[observation]]s:
#There is [[variation]] within a [[species]].
#[[Variation]]s can be passed down from parent to [[offspring]].
#[[Population]]s always produce more [[offspring]] than the environment can support which causes [[Competition (Biology)|competition]].
: This means that those with beneficial [[adaptation]]s will be more likely to survive and [[Reproduction|reproduce]]. The environment will [[Natural Selection|naturally select]] which [[organism]]s will pass on their features.
: [[Charles Darwin|Darwin]] recognised that people would not believe him.