VIII. Answer the following questions. Use all information given before:

1. How does the evolution usually take place?

2. What led Charles Darwin to develop his theory of evolution?

3. What did Darwin mean by “natural selection”?

4. What are three main observations of Darwin’s theory?

1. What does “struggle for existence” mean?

2. What book has been called the most important biology book ever written?

3. Do the majority of biologists accept Darwin’s theory?

4. What is called neo-Darwinism?

IX. Match the sentence halves. Make complete sentences:

1.	According to most biologists, the millions of species living on Earth today	A.	is called neo-Darwinism.
2.	Evolution happens	B.	than are required to replace their parents.
3.	The mechanism that is widely accepted among biologists today	C.	to support his theory and refined his ideas.
4.	Organisms produce more offspring	D.	which underpins much of modern biology.
5.	Members of the same population compete	E.	are descended from other species that inhabited the world in the past.
6.	For more than 20 years, Darwin collected evidence	F.	come about by random and spontaneous changes in genes.
7.	Evolution by natural selection has become a central theme	G.	to obtain limited resources.
8.	The variations that are so important in natural selection	H.	when the genetic composition of a population changes over successive generations.

X. Read and translate the short text without any dictionary:

Fact of life: Highly sensitive dating techniques tell us that the Earth is between 4.5 and 5.0 thousand million years old. It is generally agreed by scientists that the Earth was originally devoid of life, and that the first living organisms arose by biochemical evolution from complex organic chemicals formed in the atmosphere and seas of early Earth. These first forms of life gave rise to countless millions of species. Most have become extinct, but some have evolved into organisms found today. According to the latest estimates, 20-30 million species share our planet.

XI. Food for thought:

In 1809 Jean-Baptiste de Lamark suggested that the driving force behind evolution was the need for organisms to adapt to changing environmental conditions. His theory became known as the theory of evolution by the inheritance of acquired characteristics. He believed that adaptations developed by an organism during its lifetime could be passed on to its offspring. According to Lamark, modern giraffes might have evolved from a short-necked ancestors in the following way. Giraffes feed on leaves ripped off the branches of trees. When leaves on the lower branches were removed, or when the trees became taller, the ancestral giraffe needed to stretch to reach leaves on higher branches. By continually stretching, their necks lengthened and the ability to grow a slightly longer neck was inherited by the next generation which carried on stretching, and so on.

We know that this explanation of the evolution of the giraffe’s neck is untrue because activities such as stretching to feed do not affect the gametes. Therefore, this type of characteristic acquired during the life of an organism is not inherited by its offspring. Expressed in modern terms, Lamarckism would mean that changes in phenotype could determine the genotype of future generations. This does not agree with modern genetics, and there are no generally accepted examples of acquired characteristics being inherited. Suggest a neo-Darwinian explanation for the evolution of the modern long-necked giraffe from a short-necked ancestor.