slide1
Download
Skip this Video
Download Presentation
Charles Darwin

Loading in 2 Seconds...

play fullscreen
1 / 11

Was Darwin the First - PowerPoint PPT Presentation


  • 519 Views
  • Uploaded on

Charles Darwin Was Darwin the First? Darwin was not the first to present the concept of evolution Word first appeared in 1647 Ancient Greeks inferred that species had descended from a common ancestor Darwin referred to evolution as “descent with modification”

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 'Was Darwin the First' - Sharon_Dale


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
was darwin the first
Was Darwin the First?
  • Darwin was not the first to present the concept of evolution
  • Word first appeared in 1647
  • Ancient Greeks inferred that species had descended from a common ancestor
  • Darwin referred to evolution as “descent with modification”
  • Explained it as the differential survival of organisms following their naturally occurring genetic variation
    • Natural Selection
early influences on darwin
Early Influences on Darwin
  • Charles Lyell – geologist
  • Proposed that plant and animal species had arisen, developed variations over time and then became extinct
  • Also believed that earth’s physical landscape had changed over time
  • Thomas Malthus – proposed that populations outgrew their food supplies, causing competition between organisms and a struggle for one species to survive against another
  • Applied theory to humans, Darwin applied to all animal species
galapagos islands
Galapagos Islands
  • Darwin’s trip on the Beagle stopped in the Galapagos
  • Contained endemic species, not found anywhere else on earth
  • The species there looked similar to mainland species
  • But somehow specialized to their particular environment
    • proposed that changes were dependent on the environment
sequence
Sequence
  • 1st: Adaptations  traits occur within organisms and allow them to be more successful in the environment
  • Darwin reasoned that the importance of these adaptations was to insure the survival of reproduction of the species
  • Successful adaptations help organisms to both survive and reproduce, so these adaptations are passed on to future generations
  • Natural Selection is the mechanism that explains how changes occur within a population with favorable variations for that particular environment surviving, reproducing and passing these variations on to the next generation
    • (environments are constantly changing)
sequence6
Sequence
  • 2nd Speciation – organisms on the Galapagos Islands had become geographically separated from one another
  • Produced reproductive isolation so that there is no interbreeding between organisms of same species
    • separates the gene pools of the populations
  • Darwin theorized that within a populations of species, adaptations would arise because of reproductive isolation and would develop adaptations specific to their particular environment over time
  • Eventually this would lead to new species evolving on the different islands
    • Which is what was observed
reproductive isolation
Reproductive Isolation
  • All begins when a group becomes reproductively isolated from the rest
  • May be geographic, temporal or behavioral
    • It is most obvious in distant islands, such as the Galapagos or Hawaiian island
    • Mountains, rivers, lakes and other natural barriers can also geographically separate populations that once belonged to the same species
types of reproductive isolations
Types of Reproductive Isolations
  • Temporal isolation occurs when there is a time difference between two species
    • Such as one species of flower opening up for pollination in the morning and another at night
  • Behavorial isolation occurs when the behavior of one species does not match another
    • One mating song for one bird is not recognized by another
  • Geographic isolation is the most common method of separating two populations of a species
    • Depends on the animal involved as to what is needed to separate it
finches
Finches
  • Classic example of speciation is the 13 species of finches on the Galapagos Islands
  • Each species, descended with modifications, from an ancestral species
  • Today, the different species of finches on the island have distinct habitats, diets and behaviors depending on the current climate conditions
    • Which determines what food is available to the birds
darwin s book
Darwin’s Book
  • The Origin of Species – Presents Darwin’s theory (1859)
  • Has undergone modification and expansion and is now supported by studies in genetics and molecular biology
ad