nothing in biology makes sense except in the light of evolution theodosius dobzhansky 1900 1975 n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
"nothing in biology makes sense except in the light of evolution” PowerPoint Presentation
Download Presentation
"nothing in biology makes sense except in the light of evolution”

Loading in 2 Seconds...

play fullscreen
1 / 25

"nothing in biology makes sense except in the light of evolution” - PowerPoint PPT Presentation


  • 130 Views
  • Uploaded on

Photo by “davemee” flickr creative commons. "nothing in biology makes sense except in the light of evolution” ~Theodosius Dobzhansky (1900-1975). Statements or models that have been tested and confirmed many times. In science, the term "Theory" does not express doubt.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about '"nothing in biology makes sense except in the light of evolution”' - jena-sykes


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
nothing in biology makes sense except in the light of evolution theodosius dobzhansky 1900 1975

Photo by “davemee” flickr creative commons

"nothing in biology makes sense except in the light of evolution”

~Theodosius Dobzhansky (1900-1975)

slide3

In science, the term "Theory" does not express doubt.

    • Explain a wide variety of data & observations
    • Can be used to make predictions
    • Are not absolute, can be changed as new evidence is found
slide4

Why do so many different animals have the same structures, the arm bones in a human are the same bones as a flipper in a whale?

  • Why is the sequence of DNA very similar in some groups of organisms but not in others?
  • Why do the embryos of animals look very similar at an early stage?
slide6

Charles Darwin

  • developed the THEORY OF EVOLUTION BY NATURAL SELECTION 
  • explained how organisms changed over time  (ADAPTED)
slide7

Lamarke's Theory of Acquired Characteristics

    • Thought that you would gain or lose features if you overused or didn't use them
  • Proven to be wrong!

Photo courtesy of ucumari, creative commons, flickr

slide9

Darwin was a naturalist (what we today call biologists)

  • He traveled the world and made observations and sketches of many species
  • His most famous travels were aboard the H.M.S. Beagle where he traveled to the Galapagos Islands
slide10

Marine Iguana, photo courtesy of mtchm, flickr creative commons

Blue-footed booby, photo courtesy of stirwise, flickr creative commons

slide11

Finch, photo courtesy of stirwise, flickr, creative commons

Giant tortoise, photo courtesy of Planetgordon, flickr creative commons

slide12

Darwin noted that there existed many finches on the islands, but while they had similarities, each was adapted to eating a particular type of island food

  • He concluded that the finches all came from one ancestral species and evolved into many new species

Cactus finch, photo courtesy of zrim, flickr creative commons

slide13

Darwin published this work to explain the variety of species that exist on the planet

  • He proposed the “Theory of Evolution by Natural Selection”
slide14

1. Variation exists among individuals in a species.2. Individuals will compete for resources (food, mates, and space)3. Competition would lead to the death of some individuals while others would survive4. Individuals that had advantageous variations are more likely to survive and reproduce.

This process came to be known as Natural SelectionThe favorable variations are called Adaptations

Photo courtesy of digitalART2, flickr creative commons

slide15

Say in a species of blob….there exists blobs of all shapes and sizes (variation)

Blobs eat the little purple organisms that live underground and on the surface.

slide16

During a particularly hot year, food became less abundant (competition), blobs that had the ability to dig into the soil to get food had a better chance of survival.

Many blobs died that year…….

slide18

The next generation had move blobs with the pointed noses. That is NATURAL SELECTION.

  • Variation
  • Competition
  • Survival
  • Reproduction
slide19

Fossil Evidence

    • Shows numbers extinct animals
    • Shows similarities between extinct animals and animals that are alive today
    • The earth’s layers show a time scale of species and when they appeared on earth (and when they died out)
slide20

Dinosaurs have always fascinated us, movies such as Jurassic Park capitalize on that fascination.

How do we know what dinosaurs looked like?

We create a picture based on the bones we find (fossils) and use modern reptiles to guess at their texture and skin color.

slide21

Homologous structures – these are parts of the body that are similar, but have different functions

ex. The flippers of whales, and the wings of birds

All forelimbs of vertebrates have the same pattern of bones

• Common ancestry

slide22

Vestigial Organs – these are organs or parts that seem to have no function

Whales have pelvic bones that do not attach to legs

slide23

Biochemistry and DNA

  • When comparing the DNA of one species to another, more similarities are found in species that are more closely related.

Lion photo credit: ucumari Tiger photo credit: digitalART2

slide24

Embryological Development

Embryos of different species develop in almost identical ways.

Human fetus at 8 weeks

slide25

Direct observation of species change

    • Bacteria become resistant to antibiotics
    • Wolves were bred over many generations to become dogs (artificial selection) • and then bred further to create a variety of breeds