Initially studied medicine, then theology, before becoming a naturalist.
Traveled the world on the HMS Beagle.
Observed species relationships and distributions.
In 1859, presented the first concrete evidence and mechanism for evolution in "On the Origin of Species."
Darwin's Journey on HMS Beagle
The journey included stops at various locations around the world, including:
Azores
Canary Islands
Cape Verde Islands
Bahia
Rio de Janeiro
Montevideo
Falkland Islands
Tierra del Fuego
St. Helena
Ascension
Mauritius
King George Sound
Hobart
Sydney
New Zealand
Tahiti
Cocos Islands
Galapagos Islands
Callao
Valparaiso
Evidence Collected by Darwin
Artificial Selection
Fossil Records
Comparative Anatomy
Comparative Embryology
Biogeography
Taxonomy
Artificial Selection
Breeding for desired traits.
Examples: hens with more eggs, varieties of dogs, large vegetables.
Directly contradicts the belief that species do not change.
Dog Breed example
Wolf is the ancestor of all modern dog breeds
Bloodhound
Dalmatian
Airedale
Border Collie
Pekingese
Vegetables from One Species
Many vegetables are derived from one species, Brassica oleracea, through artificial selection for different traits.
Cabbage: Selection for terminal buds.
Cauliflower: Selection for flower clusters.
Brussels sprouts: Selection for lateral buds.
Broccoli: Selection for stems and flowers.
Kohlrabi: Selection for stem.
Kale: Selection for leaves.
Fossil Record
Fossils are evidence of past life forms and are formed in various ways:
Mineralization
Trapped in amber/tar
Footprints in soft soil
Soft vs. hard tissues
Archaeopteryx
Archaeopteryx is an example of a fossil record of a species.
Transitional Fossils
Tiktaalik roseae
A 375-million-year-old fish.
Exhibits characteristics of both fish and tetrapods.
Comparative Anatomy
Similarities in structure of functionally different organisms.
Example: Bones in Human arm, Dolphin fin, Bat wing, Bird wing
Humerus
Radius
Ulna
Carpals
Metacarpals
Phalanges
Comparative Anatomy: Homologous vs. Analogous Structures
Homologous Structures
Different species with similar underlying structure but different function.
Example: Bones of vertebrate legs, wings, and fins.
Analogous Structures
Unrelated species with similar features and function but different underlying structure.
Example: Insect wings and bird wings.
Convergent Evolution
Independent evolution of similar features or functions in unrelated species.
Example: Eye of cephalopods and vertebrates.
Convergent Evolution: The Eye
The eye of humans and octopuses are examples of convergent evolution.
Human eye components:
Eyelid
Cornea
Pupil
Iris
Ciliary muscle
Lens
Retina
Optic nerve
Octopus eye components:
Optic ganglion
Vestigial Organs
Nonfunctional, reduced parts.
Examples: appendix, wisdom teeth, coccyx in humans, vestigial pelvis in whales.
Common ancestry explains them as unused parts.
Example: Baleen whales
Vestigial hip and thigh bones
Example: Toothed whales, dolphins, and porpoises
Vestigial pelvis
Comparative Embryology
Features in embryos that do not show up in adults:
Pharyngeal pouches
Tail
Tubular heart
Suggests common ancestry.
Examples: Reptile, Bird, Pig, Human
All have gill pouches and a tail in the embryo stage
Biogeography
Study of the distribution of species.
Distinct species groups on different continents.
Example: Marsupials in Australia
Nearctic Species
Gray fox
Moose
Agouti
Beaver
Palearctic Species
Argali
Brown Bear
Black Bear
Snow Leopard
Chamois
Aoudad
Neotropical Species
Tapir
Jaguar
Sloth
Anteater
Ethiopian Species
Zebra
Lion
Oriental Species
Tiger
Indian Boar
Indian Elephant
Australian Species
Koala
Thylacine
Platypus
Kangaroo
Evidence Collected by Darwin (Recap)
Artificial Selection
Fossil Records
Comparative Anatomy
Comparative Embryology
Biogeography
Protein and DNA Sequence Data
Darwin's Conclusions from Evidence
Many species have existed before that no longer exist.
Species show relatedness in the fossil record and other forms of evidence.
Species have changed over time to their current state.
All life is related through descent with modification.
Natural Selection
Darwin proposed natural selection as a mechanism for how these changes arose.
Capacity for overproduction.
Yet few survive due to limited resources.
Individuals vary in traits.
Those that survive are those whose traits allow them to obtain resources and reproduce successfully.
Darwin's Publications
1838-43: Zoology of the Voyage of H.M.S. Beagle
1838: Part 1 No. 1 Fossil Mammalia, by Richard Owen (Preface and Geological introduction by Darwin)
1838: Part 2 No. 1 Mammalia, by George R. Waterhouse (Geographical introduction and A notice of their habits and ranges by Darwin)
1839: Journal and Remarks (The Voyage of the Beagle)
1842: The Structure and Distribution of Coral Reefs
1844: Geological Observations on the Volcanic Islands visited during the voyage of H.M.S. Beagle
1846: Geological Observations on South America
1849: Geology from A Manual of scientific enquiry; prepared for the use of Her Majesty's Navy: and adapted for travellers in general., John F.W. Herschel ed.
1851: A Monograph of the Sub-class Cirripedia, with Figures of all the Species. The Lepadidae; or, Pedunculated Cirripedes.
1851: A Monograph on the Fossil Lepadidae, or, Pedunculated Cirripedes of Great Britain
1854: A Monograph of the Sub-class Cirripedia, with Figures of all the Species. The Balanidae (or Sessile Cirripedes); the Verrucidae, etc.
1854: A Monograph on the Fossil Balanidæ and Verrucidæ of Great Britain
1858: On the Tendency of Species to form Varieties; and on the Perpetuation of Varieties and Species by Natural Means of Selection (Extract from an unpublished Work on Species)
1859: On the Origin of Species
1881: The Formation of Vegetable Mould through the Action of Worms
Darwin's Last Book
The Formation of Vegetable Mould through the Action of Worms was published 138 years ago (in Oct. 1881).
Darwin's health was failing, and he wanted to complete this book before he died.
Modern Synthesis
Darwin did not know how traits were inherited.
Gregor Mendel's work was published in 1866 but was not noticed until 1900.
Modern synthesis (neo-Darwinism) recognizes:
Mutations as the source of variations.
A change in allele frequency as a measure of evolution.