Post on 18-Jan-2016
Introduction to Evolution – Chapter 10
Freshman Honors Biology
Evolutionary Theory Timeline
1735- Carolus Linnaeus, classification 1785- James Hutton, geology 1798-Thomas Malthus, economist 1809- Jean Baptiste Lamarck, naturalist 1831 to 1835- Voyage of the H.M.S.
Beagle 1833- Charles Lyell, geologist 1858- Alfred Wallace, naturalist 1859- Charles Darwin, published
naturalist
James Hutton
Geologist Proposed that the Earth was millions
(not thousands) of years old Based on the processes of rock
upheaval (uplift) and weathering
Thomas Malthus
Economist Proposed that humans would run out of
resources like food and space if the human population numbers continue to grow
If food and space are scarce, there will be competition for them
Jean Baptiste Lamarck
French naturalist Proposed one of the first theories about
how species change over a period of time (evolution)
In Lamarck’s theory, individuals evolved
Lamarck’s Theory
Three Principles› Tendency Towards Perfection
Innate tendency towards complexity and perfection
› Use and Disuse Organism develops new adaptation by using the
structure more Organism loses an adaption by not using the
structure› Inheritance of Acquired Traits
Traits acquired by an organism can be passed on to the next generation
Charles Lyell
Geologist Published “Principles of Geology” Also proposed that the Earth is very old Proposed the forces at work in geology
today are the same forces that have shaped the structures throughout time on Earth
This had to take a long time
Alfred Wallace
Naturalist Independently proposes theory of
evolution Writes Darwin about theory prompting
him to publish his theory formed many years before
Charles Darwin
Born the same day as Abraham Lincoln
Studied theology in college Became the naturalist
aboard the H.M.S. Beagle Proposed theory of evolution
based off of observation from that trip
Published theory in On the Origin of Species in 1859
Voyage of the H.M.S Beagle
Sailed from England Traveled to
› South America› Africa› Australia› New Zealand› Galapagos
Voyage of the Beagle (cont)
Darwin studied› Difference within and between species› Living specimens› Fossils › Geology
Galapagos Islands
Group of islands off the coast of South America
Each island has a unique climate Darwin observed
› Marine iguanas› Tortoises› Finches
Darwin’s Theory of Evolution
1. Variation› Individuals naturally vary from each other› Variations that are genetically based can
be passed on from one generation to the next (although Darwin did not know how)
Darwin’s Theory of Evolution (Continued)
2. Struggle for Existence (overproduction)› Most populations grow past their resources› Organisms within a population must
compete for their share Food Space Mates Other necessities
Darwin’s Theory of Evolution (continued)
3. Survival of the Fittest (Natural Selection)
› Organisms have adaptations (inherited variations) that make them a good match to their environment (fitness)
› Individuals with better fitness survive longer and reproduce more therefore passing on their genes
› Future generation have more individuals with the well-fitted adaptation
› It is about reproduction not survival!!!
Adaptations for Fitness
Survival› Camouflage › Bright coloration› Strength› Heightened senses › Behavior
Reproduction› Strength› Costly structures› Behavior
Darwin’s Theory of Evolution (Continued)
Artificial Selection› Most fit adaptations are based on human
choices› Individuals are bred to pass on desired
traits
Darwin’s Theory of Evolution (continued)
4. Descent with Modification› Individuals have
common descent› Evolution over a long
period of time diversifies species
› All species descend from common ancestor
› Cladograms- diagram showing evolutionary relationships
Evidence for Evolution
1. Fossil Record› Darwin knew fossils represented dead
organisms› Also knew that newer organisms were
closer to the top› Record showed evidence of change over
time
Evidence for Evolution (continued)
2. Geographical Distribution of Living Species› Beaks of Galapagos Finches › Neck Length and Shell Shape for Tortoises› Various Variations for Marine Iguanas› Pattern of Organisms in Similar
Environment
Evidence for Evolution (continued)
3. Anatomy/Body Structures› Homologous
Structures that develop from the same embryonic tissues
Mature forms often have similarities but may look different and have different functions
› Vestigial Structures that no longer have a function for
an organism but are still present
Homologous Structures
Vestigial Structures
Evidence for Evolution (continued)
4. Embryology› Many embryos
look similar to each other during development and develop in similar ways
Evidence for Evolution (continued)
5. Molecular and Genetic Comparisons› Scientists compare DNA sequences and
proteins between species to support fossil and anatomy comparisons
Alligator Book p. 317