Bio 400 - Darwin

What did Darwin's idea of natural selection depend on?

each step being selectively advantageous

What can be considered the weak-point of Darwin's arguments?

genetics

What was Darwin's greatest intellectual ability?

highly synthetic mind, with a quite photographic memory, so he could remember lots of things and tie them together in his arguments when making connections

What was most of The Origin of Species devoted to?

*artificial section and natural selection* the rest showed how *common descent* explains morphological similarities in systematic groupings, *embryological similarities*, *rudimentary and vestigial organs*, the *geographical distribution of organisms*, and *fossil sequences in the stratigraphical column*

What were the 3 suggestions made about why Darwin was sick for most his life?

- Chagas' Disease (but doesnt make sense at the time he described symptoms and after the bite on the voyage) - Crohn's Disease - said that maybe it was his body punishing him for having thoughts about evolution

What three books did Darwin publish while in London, England?

- The Voyage of the Beagle (popular account of his trip) - editor of 5 vol work on the verts he had collected - The Structure and Distribution of Coral Reefs (more focussed on geological questions)

What did Darwin study when he took an 8-year break in 1854?

- barnacles - many new species were found and named by him

What were Darwin's researches at Down House (the place he lived in London)?

- barnacles - 8 years - evolution, including human evolution - earthworms - animal behaviour (expression of emotion, which he wrote a book about) - insectivorous plants - power of movement in plants - plant reproduction - domesticated plants and animals, and their variation

What did Jenkin's think about natural selection and blending?

- believed blending would happen faster than natural selection - natural selection acted on small genetic variants (individual variation) that cannot change species beyond fixed limits

What was in The Sketch of 1842 by Darwin?

- evolutionary ideas in a manuscript - wasnt published because he didnt want his ideas out yet

What was in The Essay of 1844 by Darwin?

- expanded version of the sketch about evolution - equivalent to 160 pages - not published either, but he wanted his ideas to be known at this point (showed his wife where the book was incase he died)

What were the three things Darwin wanted read at the Linnaean Society meeting in 1858?

- five page summary of Darwin's ideas, written by Darwin for this occasion - copy of Darwin's letter to Asa Gray from 1857, to show he had not stolen Wallace's ideas - Wallace's paper "On the Tendency of Varieties to Depart Indefinitely from the Original Type", 12 pages

What were Sir William Thomson (Lord Kelvin)'s thoughts on evolution and the sun?

- he didnt know what powered the sun... thought it was a gravitational collapse - concluded that the sun could not have existed for very long because it doesnt have very many energy reserves (estimated 20-40 million years)... he believed this was not enough time for Darwinian evolution to have occured

Were the observations in The Origin of Species primarily made by Darwin?

- he had heard about evolution, but he did make his own personal discovery - his book cited other works, but none were directly associated with evolution (he wasnt interested in Lamarck or his grandfather ect)

How was Darwin (1809-1882) free of financial worries?

- he inherited a lot of money from his grandfather Robert Erasmus who had a very successful medical practice, and he did not have many siblings - he wrote best selling books - he invested in the English Economy which was very strong at the time (you almost couldnt lose money, and he multiplied his already had fortune)

Did Sir William Thomson (Lord Kelvin) affect Darwin at all?

- intimidating to Darwin because at this time physics was so successful at explaining things during his time and Darwin was also uncomfortable with numbers - was a serious objection to his ideas and wasnt accounted for until after Darwins death

What what the Beagle's role? Why was Darwin invited on the voyage?

- job of the Beagle was to survey coast of South America (where some fossils were found that were important in his first thoughts on evolution) - problem of social isolation, social class, and lack of education for captains of these types of voyages - Captain Fitsroy had served under another captain that committed suicide, so he wanted someone to come so that this didnt happen to him - therefore Darwin was essentially invited for companionship

What happened when Darwin went back to London, England?

- married Emma Wedgewood (wrote down pros and cons... this was his cousin) - published 2 books and editied volumes on vertebrates - began secretly thinking about evolution - his health deteriorated and remained poor the rest of his life (had upset stomach, vomiting, trembling, boils, anxiety)

Why did Darwin go to Cambridge? Was he religious at this time? Was he studios?

- preparation for clergy - Dawrin did not have any doubts of christianity at the time of Cambridge (he later lost them) - thought the clergy was a good idea because it was respectable - he spent his time drinking, playing cards, hunting, and generally having a good time - he read a book about functional zoology in a theological context (said to be the beginning of his thoughts on natural selection) - however, he did graduate quite high in his class

What did finches have to do with Darwin's thoughts on evolution?

- thought that island finches must be related to finches on mainland, but had been modified from living in different habitats - led to the idea of migration and adaptation with concept of biogeography

Did Fleeming Jenkin agree with Darwinian evolution? Why or why not?

- thought that the kind of evolution that Darwin had in mind was not consistent with what he thought about hereditary and nature of species - thought natural selection could not alter a species beyond certain limits of a sphere (kind of described essentialism; centre of a fixed radius)

What was Darwins response to Jenkin?

- thought the issue of blending inheritance was not important because the individual variation he thought was continuously being introduced and would therefore keep pace with blending inheritance - so with each generation, new variance would arise which natural selection would then act upon - reacted to sphere analogy by saying maybe todays outer line would be tomorrows centre; saying it doesnt represent anything essential in the Plutonic sense

What were the two kinds of debate that arose during "The Reception"?

- whether Darwin was correct or not, and if he were... - what the meaning of evolution might be for society, morality, and philosophy

What were Darwin's causes of evolutionary change? What was the evidence for them?

1. *Natural Selection* (evidence was artificial selection and inherited variability... he bred pigeons, and knew it was possible to tease out differences, but couldnt really support the genetic theory behind the inherited variability. He didnt think natural selection could be observed in the field because it happens too slowly) 2. *Use and Disuse* (less well known. Accepted to some extent Lammarkean inheritance of acquired characteristics. (recall his mechanism of evolution had to do with strengthening and weakening) (eg. Cave Fish lost Eyes: if it was in darkness, it wouldnt have any reason for eyes, and so since they were not doing anything, they would wither away in an inheritable fashion. Can also understand this on a basis of natural selection)

What were Darwin's achievements?

1. made convincing case for the *reality of evolutionary change* (was the first case to be accepted among biologists) 2. *killed essentialism* in biology 3. presented reasonable mechanism for evolution: *natural selection* 4. explained the apparent *design and purpose in organisms* in a natural wa. He banished teleological explanation from biology (you now see function rather than purpose)

What were Darwin's types of variation?

1. sports: refers to come largely conspicuous variance 2. individual variation: (aka continuous variation) referred to inherited variation that were the opposite of sports, and were small and incremental

By ______, Darwinism is dead... What does Darwinism refer to here?

1900; evolution by natural selection (NOT just evolution)

In 1858, ___________, an English naturalist living in Indonesia wrote a brief outline by natural selection (however, didnt address it as natural selection) and sent it to Darwin for his opinion (unaware that Darwin had been working on the same issue).

Alfred Russel Wallace (went to S. America and collected plants and animals, but everything sunk in a ship)

What did Darwin do after hearing from Wallace?

He took the advice from Lyell and Hooker, but was unable to communicate with Wallace quickly. He arranged for 3 papers to be read at a meeting of the Linnaean Society on July, 1, 1858.

In 1856, Darwin began writing a 1000-page book he intended to call _______, encourage d by Lyell and Hooker, who had warned him someone might scoop his ideas if he didnt get it out there soon

Natural Selection

Was the Origin of Species by Darwin hard to understand for the general public?

No, Darwin wanted it to be comprehensible to everyone so his ideas could be widely distributed and he knew that the some of the general public were already on board with evolution

Did Darwins father approve of him going to the Beagle?

No, but said he might change his mind if someone he respected said it was a good idea, so he went to his uncle and asked him to convince his father that going to the Beagle was a good idea

Did Darwin ever finish writing Natural Selection?

No, he abandoned it and began writing a shorter presentation of his ideas... The Origin of Species (it was written in 15 months, during very bad health)

Did Darwin have an in-depth view on heritability?

No, he didnt have an elaborate model of heritability. Thought there were two kinds of variance

- one of the most outstanding physicists of his day - originated the Kelvin temp scale - known for two things that turned out to be very wrong: (1) physics was a completed science and had nothing else to offer, (2) evolution

Sir William Thomson (Lord Kelvin)

Why did Darwin keep his 1844 essay a secret?

Some hypotheses include: - maybe it was too short and he wanted it longer - maybe he wanted to solidify his reputation as a natural historian first - 1844 is the year the Vestiges (by Robert Chambers) was published (which was unpopular), and he didnt want to associated with the controversy (however, he followed all of the objections, and was happy to find that he had already thought of them and rebutted them, making him feel scientifically untouchable)

Darwin's father sent him to the _________ to study medicine, but he lacked interest and motivation... why?

University of Edinburgh (one of the best schools in the world) - he didnt really have any calling for medicine. - he was interested in science, but he was horrified when watching surgery, especially when on a child - he hated going to class

Why was Darwin never knighted?

all of his friends were, so it was kind of odd. Turns out he was supposed to be knighted basically every year. However, knighthood is supposed to be uncontroversial. Since his ideas were so new and controversial, being knighted never worked out

Darwin also searched for a cause of evolutionary change. He wondered what natural phenomenon could select for certain inherited traits the way _________ could. This led to thoughts on?

artificial selection; led to thoughts on natural selection (even though he had thought about it earlier, this solidified his confidence on it) - had to find some natural process that could lead to different chances for survival among offspring - believed that this chance was due to ability to live in environment - led to natural selection and how the environment chooses traits

What are gennules? What do they have to do with herditary factors?

believed in hereditary particles called "gennules" that were carried to the sex cells and held information about the experience of the organism (same view as the Hippocratics)

What was Jenkin's idea "blending"?

blending was a model of inheritance (eg. red and white snapdragon flower makes a pink flower)

A.W. Bennett's thoughts on Natural Selection?

cannot fashion complicated adaptations requiring many steps, because each step would have to be both small but adaptive

While at Edinburgh, Darwin became interested in ____ and ______. He met Robert Grant, a zoologist at Lamarckian, and Robert Jameson. What did Darwin learn from them?

natural history and geology - learned how to be a naturalist in the field and research in a more systematic way - the idea of doing manipulation and having variables ect was not apparent yet... it was moreso an attempt to understand nature - however, he flunked out and had to go home

What did Darwin think was strong evidence of natural selection? Were there complications?

proposed that certain butterfly was toxic, and another non-toxic butterfly was replicating its appearance - there were complications as to deciding how many "steps" this required, so he questioned whether each step provided an advantage - can now show this using Mendalian genetics, but obvs they didnt have this yet

What is the Wallace Line?

represents a discontinuity of flora and fauna on either side of this line (if you look closely, Bali and Lombok are separated by this line yet were very close together)... he was on board with evolution from the very beginning

Did people only reject evolution because of religion?

some people rejected evolution simply because it was difficult to understand and out of our control, regardless of religion or science

What was evolution referred to at the time Darwin was in England?

species transmutation

In July 1837, Darwin began a notebook on _________. What did this convince him of?

species transmutation; that evolution occurs

What did Jenkin's think about genetic variants (sports)?

that they will quickly be blended out by sexual reproduction, because offspring tend to be intermediate in appearance relative to their parents

What evolution accepted readily within science?

yes, the reality of evolutionary change was accepted quickly. however, the theory of natural selection came under attack from many scientific critics