Natural selection:

___________ is the driving force of evolution.    

• The changes can occur in many forms.
• With time small changes occur in the organism and these make them different than other animals of the same category. Thus variations occur. 
• Mutations are sudden changes that occur at the molecular level, it changes the genome of an organism.
• Sexual reproduction is also a source of change. As it also causes variations in offspring's. At the time of gamete formation some changes occurs due to recombination.
• So, among all the changes that occurs with time only those will develop that help the organism to remain alive.
• This is called natural selection.

Tortoises with dome-shaped shells have shorter necks because:

• Dome shaped tortoises are larger.
• These have shorter neck because these feed on the vegetation that is closer to the ground.
• So, they are able to eat with shorter neck.

Rheas are flightless birds found in ___________.

• Rheas are flightless birds that show similarities with ostrich.
• These belongs to the order Rheiformes.
• These are also called American ostrich because these are found only in South America.
• These have comparatively larger but nonfunctional wings.
• These are able to swim.

Charles Darwin was best known naturalist in the 19^th century for:

• Charles Darwin during his travel of Galapagos Island, noticed different organisms of different places of same geographic area.
• On the basis of his observations, he gave the theory of natural selection.
• According to the theory of natural selection, only those species can survive in the changing environment which develop such variations that helps them to remain alive. 
• This theory helped to understand the process of evolution properly.
• So, this was an acceptable idea for scientists.

The dome-shaped tortoise came from which islands?

• Dome shaped tortoises are found in Isabele Island.  
• These are found in moist areas and are adapted to feed on vegetation that is closer to the land.
• Darwin noticed some differences among tortoises that he found in Galapagos Island and other islands. These were different in size and shape.
• These differences of tortoises supported the theory of natural selection.

How many species of finches were observed by Darwin on the Galapagos?

• While traveling through the island, Darwin noticed some birds.
• These birds had different sizes and shapes of their beak.
• The structure of their beak was changed due to adaptations.
• All of these birds were evolved from same ancestors. Just their beak was different.
• The shape of their beak was changed according to their feeding habits.
• So, he observed 13 such finches.

______________ is a force that causes groups of organisms to change over time.

• A group of organism changes overtime because of variations.
• These variations are caused during sexual reproduction.
• Changes are also caused by mutations. These are sudden changes that are caused on genetic level. 
• So, all these changes caused in a group of organisms are developed in next generations only if these are helpful for them to survive in the changing environment.
• This is called adaptation. Only such changes are developed in generations of organism that helps them to evolve.
• So, nature selects only those who can survive better in the changing environment. This is called natural selection.
• This concept was given by scientist Charles Darwin. So, natural selection acts as a force that causes group of organisms to change overtime.

In this case if the surface was a sand hill instead of a rocky mountain which mice population would survive better?

Who is considered as the “Father of evolution”?

Tortoises with saddle-shaped shells have shorter necks as they feed on grass.  

Artificial selection is used to produce organisms with:

Darwin published his theory of evolution in his book named:

Natural selection favored melanic moths to survive in industrial areas because?

Changes caused by the environment in the phenotype are not significant in the process of evolution of new species because:

The deer mouse in sand hills of Nebraska are ___________ in color.