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Evolution A population changes over time.

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Presentation on theme: "Evolution A population changes over time."— Presentation transcript:

1 Evolution A population changes over time

2 Charles Darwin ( )


4 22 years old, 5 years


6 Lamarck- Inheritance of Acquired Characteristics
At least he sees that organisms change- gets a bad rap If you cut a mouse tail off children will still have tail- not changing the genes Characteristics gained after birth – cannot be passed on through reproduction


8 Must be Genetic You cannot “ force” yourself to have a characteristics
Ex. You cannot force yourself to be lactose tolerant Bacteria CANNOT acquire resistance to antibiotics New traits cannot be created during your lifetime Only genes can be passed on

9 Lyell HISTORY OF THE EARTH CALENDER is 4.5 Billion years old
The other idea was that Earth itself is less than 10,000 Lyell proposed that gradual and observable geologic processes such as erosion could explain the physical features of today's Earth. thousands or millions of years

10 Earth 4.5 billion years old 3.5 billion years first life ( single celled)

11 Fossils Shows earth is old – there is enough time for descent with modification to occur


13 Darwin’s Finches Biogeography- geographic distribution of life forms
Galapagos Islands- Volcanic islands off the coast of South America Species were slightly different than the ones on the mainland Finches- different beaks depending on the food available Cactus eating finch-more point beak Insect eating finch- sharp ( trees) Types of seeds All descended from one mainland Finch DESCENT WITH MODIFICATION from a COMMON ANCESTOR








21 The Galápagos tortoise or Galápagos giant tortoise the largest living species of tortoise and 10th-heaviest living reptile, reaching weights of over 400 kg (880 lb) and lengths of over 1.8 meters (5.9 ft). hell size and shape vary between populations- humidity, dryness ect

22 Only swimming marine iguana-

23 Galapagos Land Iguana

24 Blue Footed Boobie blue feet and dancing to impress the female.mating ritual


26 Frigatebird- Do this to distract others and take their prey


28 Natural Selection Mechanism for evolutionary change
Inherited variations: Mutations- changes in DNA Meiosis Not all individuals survive Adaptations( traits that help an organism be more suited to the environment) increase survival and reproductive success ( Fitness- reproductive success) Genes for adaptations increase in each generation LACKS DIRECTION – if environment change- not going towards a “BEST” Extinction- previous adaptations are no longer suitable to changed environment

29 Artificial Selection Breeder choices which traits to perpetuate ( dogs descended from wolves) Canis familiaris comes from canis lupis domesticated 14, 000 years ago Natural selection would never have selected dogs with long ears ( ear infetions)


31 The result of Natural Selection is a population adapted to the local environment

32 Types of Natural Selection
Directional- one trait is favored, ex beak size Stabilizing- population stabilizes on a particular trait, example birth weight Disruptive- which extreme values for a trait are favored over intermediate values- beak size

33 Evidence for Evolution
Fossils Biogeographical Anatomical Biochemical Embryology Examples- Antibiotic

34 Fossils

35 8 million years ago humans chimpanzees - dozen human like species called hominids
The modern form of Homo sapiens first appeared about 100,000 years ago. This species is distinguished by large brain size, mouth not as protruding Begin with bipedal ancestor- skulls begin when humans began to walk on two feet

36 Lucy, after the Beatles song "Lucy in the Sky with Diamonds", which was being played loudly and repeatedly on a tape recorder in the camp.[3]

37 Lucy- The discovery of this 3
Lucy- The discovery of this 3.2 million yearshominin was significant as the skeleton shows evidence of small skull capacity akin to that of apes and of bipedal upright walk akin to that of humans, providing further evidence supporting the view that bipedalism - Australopithecus afarensis

38 Biogeography A mammal of an order (Marsupialia) whose members are born incompletely developed and are typically carried and suckled

39 Anatomical Evidence a. Homologous Structure: Structures that are similar because they are inherited from a common ancestor

40 Anatomical Evidence b. Analogous Structures: features are similar in function but not in structure. They do not derive from a recent common ancestor but in response to a similar environment.


42 Anatomical Evidence C. Vestigial structures: no longer have function. occur because organism inherit anatomy from their ancestors. Ex. Some snakes have small hindlimbs Humans: Appendix, wisdom teeth, tail bone

we can’t digest cellulose (in leaves, barks of trees VESTIGIAL STRUCTURE




47 Biochemical Living organisms use DNA, and many identical enzymes (same 20 amino acids) Degree of similarity of DNA sequence or amino acid structure based on how closely related

48 Embryology( Development)

49 Embryology (Development)
Embryos of closely related organisms often have similar stages in development.

50 Causes of Microevolution
Mutations are the raw material for evolutionary change Gene Flow- Non random mating Genetic Drift

51 Speciation ( Macroevolution)

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