Darwins concept He was born February 12th 1809 Darwin developed the biological theory of evolution that explains how modern organisms evolved over long periods of time through descent from common ancestors. In 1831, he began a 5 year voyage on the HMS Beagle that would change his life. Darwin thought about the patterns he’d seen on his voyage He realized that there were many similarities between the animals he’d seen There was evidence that suggested that species were not fixed and that they could change by some natural process Proposed that the use or disuse of organs caused organisms to gain or lose traits over time. These new characteristics could be passed on to the next generation. Lamarck’s hypotheses were incorrect in many ways However, Lamarck was one of the first to: Suggest that species are not fixed Explain that evolution uses natural processes Recognize that there is a link between an organism’s environment and its body structures Lamarck’s work paved the way for later biologists, including Darwin In 1798, Thomas Malthus noticed that people were being born faster than people were dying. How this helped Darwin He reasoned that what Malthus proposed for human populations also applied to all living things. Struggle for Existence From Malthus’ theory of supply and demand, Darwin reasoned that if more individuals are produced than can survive, they will have to compete for food, living space and other necessities of life Darwin described this as the struggle for existence Individuals have natural variations among their inheritable traits Fast predators capture prey more efficiently Prey that are faster, better camouflaged or better protected avoid being caught. Any heritable characteristic that increases an organisms ability to survive and reproduce in its environment is called an adaptation’’ Ability to survive and reproduce in a specific environment is called FITNESS Fitness is a result of adaptation Good adaptations allow organisms to survive and are passed on to their offspring. Good fitness: reproduce Low fitness: few offspring/extinction

1. DARWIN’S
CONCEPT Ayesha safdar
17130814-029
Evolution and systematics
Msc-2nd

2.  He was born February 12th 1809
 Darwin developed the biological theory of evolution that
explains how modern organisms evolved over long periods
of time through descent from common ancestors.

3. In 1831, he began a 5 year voyage on the HMS Beagle that
would change his life.

4.  Darwin thought about the patterns he’d seen on his voyage
 He realized that there were many similarities between the animals
he’d seen
 There was evidence that suggested that species were not fixed and
that they could change by some natural process
Putting the Pieces of the Puzzle Together

5. Lamarck’s Evolutionary Hypotheses
Proposed that the use or disuse of organs caused
organisms to gain or lose traits over time.
These new characteristics could be passed on to the next
generation.

7. Evaluating Lamarck’s Hypotheses
Lamarck’s hypotheses were incorrect in many ways
However, Lamarck was one of the first to:
• Suggest that species are not fixed
• Explain that evolution uses natural processes
• Recognize that there is a link between an organism’s
environment and its body structures
Lamarck’s work paved the way for later biologists,
including Darwin

8. Population Growth
In 1798, Thomas Malthus noticed that people were being
born faster than people were dying.
How this helped Darwin
• He reasoned that what Malthus proposed for human
populations also applied to all living things.

9. Artificial Selection

10. Struggle for Existence
From Malthus’ theory of supply and demand, Darwin
reasoned that if more individuals are produced than can
survive, they will have to compete for food, living space
and other necessities of life
Darwin described this as the struggle for existence

12. Variation and Adaptation
• Individuals have natural variations among their inheritable traits
• Fast predators capture prey more efficiently
• Prey that are faster, better camouflaged or better protected avoid
being caught.
• Any heritable characteristic that increases an organisms ability to
survive and reproduce in its environment is called an adaptation’’

13. Survival of the Fittest
Ability to survive and reproduce in a specific
environment is called FITNESS
Fitness is a result of adaptation
Good adaptations allow organisms to survive and are
passed on to their offspring.
Good fitness: reproduce
Low fitness: few offspring/extinction

14. Natural Selection
o He referred to “survival of the fittest” as Natural
Selection
Natural Selection is the process by which organisms with
variations most suited to their local environment survive
and leave more offspring

15. DARWIN'S FOUR POSTULATES
Individuals within species vary
Some of these variations are passed on to offspring
Individuals vary in their ability to survive and reproduce
Individuals with the most favorable adaptations are more
likely to survive and reproduce.

16. The Evolution of the Horse

17. If we look back far enough we could find the common
ancestors of all living things.
A single “tree of life” links all living things
This is known as the principle of common descent.

18. Biogeography
 Biogeography is the study of where organisms live now
and where they and their ancestors lived in the past
 Two biogeographical patterns are significant to Darwin’s
theory:
Closely Related but Different
Distantly Related but Similar

19. Darwin noticed that all the birds he had collected throughout the
Galapagos were all finches

20. THANK YOU…