slide1 n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Evolution PowerPoint Presentation
Download Presentation
Evolution

Loading in 2 Seconds...

play fullscreen
1 / 30

Evolution - PowerPoint PPT Presentation


  • 139 Views
  • Uploaded on

Evolution. Evolution. What is evolution? It is the process of biological change by which descendents come to differ from their ancestors. Scientists. Scientists who began studying evolution: Linnaeus (1700’s) Developed classification system of organisms

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 'Evolution' - genna


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
evolution
Evolution
  • What is evolution?
    • It is the process of biological change by which descendents come to differ from their ancestors
scientists
Scientists
  • Scientists who began studying evolution:
    • Linnaeus (1700’s)
      • Developed classification system of organisms
      • Proposed that organisms arose from hybridization
scientists1
Scientists
  • Buffon (1700’s)
    • Used evidence of past life
    • Proposed that species shared ancestors instead of arising separately
    • Proposed earth was much older than 6000 years
scientists2
Scientists
  • Erasmus Darwin (1731)
    • Proposed all living things were descended from a common ancestor
    • Later expanded upon by his grandson
scientists3
Scientists
  • Lamarck (1809)
    • Didn’t believe in extinction
    • Species evolved instead
    • Proposed that changes in environment caused behavior to change
    • Organism passes on these traits to offspring
    • “Inheritance of acquired characteristics”
charles darwin
Charles Darwin
  • Darwin took a trip to the Galapagos Islands aboard the HMS Beagle
  • He studied the inhabitants of the island
charles darwin1
Charles Darwin
  • Findings and conclusions:
    • Variation among species
    • Led him to believe species adapt to their environment
    • Adaptation- feature allows an organism to better survive in an environment
    • Leads to change in populations over time
slide11

horned lizard

pistol shrimp

aye aye

archer fish

charles darwin2
Charles Darwin
  • Natural Selection
    • Individuals inherit beneficial adaptations and produce more offspring than others
charles darwin3
Charles Darwin
  • 4 principles of natural selection:

1. Variation

- Differences among organisms

2. Overproduction

- More offspring increases chance for survival

3. Adaptation

- Certain variations allow to survive better

4. Descent with Modification

- Over time, more individuals in the population will have the beneficial traits

natural selection
Natural Selection

Variation

Overproduction

Descent with Modification

Adaptation

fossil evidence
Fossil Evidence
  • No fossil evidence that contradicts evolution has been found
  • Allows us to see transitions of species over time
anatomical evidence
Anatomical Evidence
  • Homologous structures
    • Features that are similar in structure, but different in function in different organisms
    • Supports common descent
anatomical evidence1
Anatomical Evidence
  • Analogous structures
    • Structures that perform similar function
anatomical evidence2
Anatomical Evidence
  • Vestigial structures
    • Unused features
    • Structure had a function in early ancestor
    • Helps support common ancestry and evolution
molecular evidence
Molecular Evidence
  • All living things have DNA
  • Organisms carry pseudogenes
    • Genes that do not function (vestigial)
  • Cells have very similar proteins
    • Marine worms have same proteins in the eye as vertebrates
  • Comparison of milk protein in whales and hippos:
  • Hippo

TCC TGGCA GTCCA GTGGT

  • Humpback Whale

CCC TGGCA GTGCA GTGCT

population distributions
Population Distributions
  • Normal Distribution
    • Frequency of a certain phenotype is near the mean
population distributions1
Population Distributions
  • Directional Selection
    • Selection favors phenotypes at one extreme
    • Population shifts toward advantageous trait
population distribution
Population Distribution
  • Stabilizing Selection
    • The intermediate is favored and becomes the most common
population distribution1
Population Distribution
  • Disruptive Selection
    • Both extreme phenotypes are favored
genetic drift
Genetic Drift
  • Bottleneck Effect
    • Occurs after an event greatly reduces the size of a population
    • Ex. Overhunting of elephant seals
genetic drift1
Genetic Drift
  • Founder Effect
    • Occurs after a small # of individuals colonize a new area
    • Ex. Emerald ash borer
sexual selection
Sexual Selection
  • Occurs when certain traits increase mating success
  • Two types:
    • Intrasexual
      • Physical competition among males
    • Intersexual
      • Displays among males
  • Examples:
    • Intrasexual
    • Intersexual

Bird display

Giraffe fight

evolutionary classification
Evolutionary Classification
  • Cladogram
    • Evolutionary tree that proposes how species may be related to each other through common ancestors
  • Clade
    • Group of organisms that share certain traits
evolutionary classification1
Evolutionary Classification

Cladogram for modes of transportation:

Bicycle

Car

Motorcycle

Airplane

On foot

walking

bicycle

motorcycle

car

airplane

wings

Passengers

enclosed

motor

wheels