Introducing
Prezi AI.
Your new presentation assistant.
Refine, enhance, and tailor your content, source relevant images, and edit visuals quicker than ever before.
Trending searches
Loading…
Charles Darwin
4
Transcript
Charles Darwin
Bertino, Buri, Conti, Lavigna, Orecchia, Rossetti
Charles Darwin
EARLY LIFE
- February 12th, 1809 in Shrewsbury - April 18th , 1882
- His grandfathers: Erasmus Darwin and Josiah Wedgewood --> Lunar Society
- His father Robert Darwin
- When he was 8, his father transferred him to the Shrewsbury School
- At the age of 16, he became a medical student at the University of Edimburgh
EDUCATION
- His inclination toward science was considerably strengthened at Edinburgh both by some fine scientific lectures in chemistry, geology and anatomy and by the mentoring of Dr. Robert Grant
- He was introduced to marine invertebrate anatomy and the use of the microscope as a scientific tool
- Darwin joined an Edinburgh scientific society, the Plinean society
- He finally broke the news of his distaste for medicine to his father, thus he attended Christ College, Cambridge University, where he studied Divinity until he graduated in January of 1831.
- Darwin was introduced to the men whose ideas were currently being debated in geology and natural history
During my last year at Cambridge, I read with care and profound interest Humboldt’s Personal Narrative. This work, and Sir J. Herschel’s Introduction to the Study of Natural Philosophy, stirred up in me a burning zeal to add even the most humble contribution to the noble structure of Natural Science. No one or a dozen other books influenced me nearly so much as these two.
- Tours of England and Wales
- He eventually decided to leave on a journey to South America
- Darwin would not sail as a lowly surgeon-naturalist but as a self-financed gentleman companion to the 26-year-old captain, Robert Fitzroy
VOYAGE OF BEAGLE
- December 27th, 1831 - October 2nd, 1837
- The Beagle, a British Royal Navy’s survey ship
- Purposes of the voyage: Provide maps of South America useful to the British Navy. Britain viewed South America as a market for its manufactured products and as a source of raw materials.
- Darwin paid for his place on the ship but he had the liberty to collect specimens and send them back for his own use
Darwin's Observations
- He saw far more diversity during his travels
- He began to realize that an enormous number of species inhabit the Earth
Patterns of Diversity
patterns of diversity
- Darwin was intrigued by the fact that so many plants and animals seemed remarkably well suited to whatever environment they inhabited
- He was impressed by the many ways in which organisms could survive and produce offspring
- He wondered if there was some process that led to such a variety of ways of reproducing
Patterns of Diversity
- Darwin was also puzzled by where different species lived—and did not
- He visited Argentina and Australia, for example, which had similar grassland ecosystems
- Those grasslands were inhabited by very different animals
Living Organisms and Fossils
- during his voyage, Darwin collected the preserved remains of ancient organisms, called fossils
living organisms and fossils
Galapagos Islands
GALAPAGOS ISLANDS
- They are a group of small islands located West of Ecuador, in the Pacific Ocean
- Darwin noted that although they were close , the islands had very different climates
- The smallest, lowest islands were hot, dry, and nearly barren
- Hood Island, for example, had sparse vegetation
- The higher islands had greater rainfall and a different assortment of plants and animals
- Isabela Island had rich vegetation
The Galapagos Islands
- Darwin also saw several types of small, ordinary-looking brown birds hopping around, looking for seeds
- He thought that some of the birds were wrens, some were warblers, and some were blackbirds
- As Darwin examined the birds, he noted that they had differently shaped beaks
observations
Ideas That Shaped Darwin's Thinking
INFLUENCES
- Most Europeans in Darwin's day believed that the Earth and all its forms of life had been created only a few thousand years ago
- A robin, for example, has always looked and behaved as robins had in the past
- Rocks and major geological features were thought to have been produced suddenly by catastrophic events that humans rarely, if ever, witnessed
HUTTON AND LYELL
- During the eighteenth and nineteenth centuries, scientists examined Earth in great detail
- Hutton and Lyell helped scientists recognize that Earth is many millions of years old, and the processes that changed Earth in the past are the same processes that operate in the present
Lamarck's theory
- The French naturalist Jean-Baptiste Lamarck was among the first scientists to recognize that living things have changed over time—and that all species were descended from other species
- Lamarck proposed that by selective use or disuse of organs, organisms acquired or lost certain traits during their lifetime
- These traits could then be passed on to their offspring
- Over time, this process led to change in a species
Lamarck's theory
MALTHUS
- Another important influence on Darwin came from the English economist Thomas Malthus
- In 1798, Malthus published a book in which he noted that babies were being born faster than people were dying
- Malthus reasoned that if the human population continued to grow unchecked, sooner or later there would be insufficient living space and food for everyone
- The only forces he observed that worked against this growth were war, famine, and disease
Malthus theory
- England became quieter and more prosperous in the 1850s
- The world was becoming safer for Darwin and his theory: mid-Victorian England was stabler than the “hungry Thirties” or turbulent 1840s.
- Through 1855 Darwin experimented with seeds in seawater to prove that they could survive ocean crossing
- Darwin perfected his analogy of natural selection with the fancier’s “artificial selection,” as he called it.
- In April 1856, Darwin began writing a triple-volume book, tentatively called Natural Selection
- Alfred Russel Wallace, an English socialist, sketching a similar-looking theory.
- they read joint extracts from Darwin’s and Wallace’s works at the Linnean Society on July 1st, 1858.
- he missed the first public presentation of the theory of natural selection.
- On the Origin of Species by Means of Natural Selection, or the Preservation of Favoured Races in the Struggle for Life.
- radical Dissenters were sympathetic, as were the rising London biologists and geologists, even if few actually adopted Darwin’s cost-benefit approach to nature.
THE THEORY OF EVOLUTION
- The main premise underlying Darwinian evolution is that the living world is always changing and with hereditary continuity from past to present life.
- Darwin noted that plant and animal breeders used heritable variation—what we now call genetic variation—to improve crops and livestock
- Darwin termed this process artificial selection
- In artificial selection, nature provided the variation, and humans selected those variations that they found useful
THE THEORY OF EVOLUTION
The fossils evidence
- A fossil is a remnant of past life uncovered from the crust of the earth.
- They reveal profound changes in the earth's environment, including major changes in the distributions of lands and seas.
- The fossil record is biased because preservation is selective.
- Fossils form in stratified layers with new deposits lying on top of older ones.
Fossil Record
Evolutionary trends
- The phrase "evolutionary trend" does not imply that more recent forms are superior to older ones or that the changes represent progress in adaptation or organisms complexity.
- Although Darwin predicted that such trends would show Progressive adaptation, many contemporary paleontologists consider progressive adaptation rare among evolutionary trends.
Evolutionary Trends
Common descent
- Darwin proposed that over long periods, natural selection produces organisms that have different structures, establish different niches, or occupy different habitats
- As a result, species today look different from their ancestors
- Each living species has descended, with changes, from other species over time
- He referred to this principle as descent with modification
- According to this theory, we should be able to trace the genealogies of all modern species backward until they converge on ancestral lineages shared with other species, both living and extinct.
Common Descent
The power of a theory
- Darwin's theory of common descent illustrates the scientific importance of general theories that give unified explanations to diverse kinds of data. Darwin proposed his theory of descent with modification of all living forms because it explained the patterns of similarity and dissimilarity among organisms in anatomical structures and cellular organization.
The power of a theory
Natural selection
Natural Selection
1. Species are comprised of individuals that vary ever so slightly from each other with respect to their many traits.
2. Species have a tendency to increase in numbers over generations at a geometric rate.
3. This tendency is checked, to use the language of Thomas Malthus’ On the Principle of Population, by limited resources, disease, predation, and so on, creating a struggle for survival among the members of a species.
4. Some individuals will have variations that give them a slight advantage in this struggle, variations that allow more efficient or better access to resources, greater resistance to disease, greater success at avoiding predation, and so on.
5. These individuals will tend to survive better and leave more offspring.
6. Offspring tend to inherit the variations of their parents.
7. Therefore, favourable variations will tend to be passed on more frequently than others and thus be preserved, a tendency Darwin labelled ‘Natural Selection’.
8. Over time, especially in a slowly changing environment, this process will cause the character of species to change.
9. Given a long enough period of time, the descendant populations of an ancestor species will differ enough both from it and each other to be classified as different species, a process capable of indefinite iteration. There are, in addition, forces that encourage divergence among descendant populations, and the elimination of intermediate varieties.
CONCLUSION
Choose a template
Presentations from around the world
Learn more about creating dynamic, engaging presentations with Prezi