Week 1 Flashcards
How does science research work?
Identify problem & raise a question
Collect data by observation and/or experiment
Generate a hypothesis
Collect more data
Reject or amend hypothesis
What did Aristotle (c300 BC) say about evolution?
Life arises out of nothing!
Evidence: birds in the sky that weren’t there before were now there, flowers grew in spring that weren’t there before
What did Redi (1668) test due to Aristotle’s hypothesis?
He compared covered and uncovered meat to understand the origins of life.
Flies only came to, and laid eggs on, the uncovered meat - therefore only maggots “arose” from the uncovered meat.
What did Redi (1668) conclude?
That in order to have life, life has to already exist it’s not spontaneous
For example; flies laid eggs, which ‘grew’ maggots
How has life on earth become to be diverse and complex?
Evolution!
What is evolution?
Evolution explains components of individuals and how populations interact with eachother, and pass on advantageous alleles to aid their survival!
It helps us understand change (natural selection) processes so we can manage them to our benefit. For example: conservation
What book did Darwin publish
(1859)?
Origin of Species by Means of Natural Selection
What did Wallace do? (1823-1913)
Contemporary of Darwin, who worked independently and came up with the same idea/theory of evolution by his own means of research and study.
What did Wallace and Darwin present?
A joint paper which proposed their ideas on evolution!
Who is the forgotten father of evolutionary thought?
Alfred Russel Wallace
(1823-1913)
How do organisms show variation,
By individual features and traits within their species.
For example, ginger hair or brown hair!
What variation is heritable?
Traits and features within species! This is so offspring resemble their parent
(However other factors such as the environment may also affect traits and features within soecies)
What encourages competition?
Limited responses within and between species as there is an over production of offspring than can be maintained.
What is selection in evolution?
Individuals live or die depending on the presence/magnitude of the trait which influences the outcome of the competition.
This is called evolution and results in adaptation or changes in traits within populations! If an organism survives and reproduces, it passes on the advantageous alleles/features to the next generation (which is also a source of evolutionary change)
Changing allele frequencies within populations and changing species is a consequence of what?
The evolutionary selection process.
Advantageous alleles pass onto next generations which leads to adaptations within species. Changes in traits to aid an organisms survival
Why/when did Darwin form his theory?
Started working as a civilian in a Royal-Navy ship that was going on a mapping excursion around the globe and aimed to bring back specimens for museums.
His observations on the Galápagos Islands, of finches, encouraged his interest - why did they have differing beaks and feed on different insects yet look similar? Did they all look the same and change over time? Did they have a common ancestor?
What did Darwin conclude?
Due to different opportunities within the environment the birds were in, they evolved to be able to explore the different environmental opportunities. Which therefore brought on evolutionary change within the birds.
After finding out about finches, Darwin conducted his own research.
What did he do?
His own observations where he artificially selected and bred pigeons and plants. He selected for behaviour and traits within them!
He concluded that evolution is a selection process and while used for human entertainment/research, may also happen in the wild to aid survival and enhance reproduction within organisms
Who came up with a classification scheme of species - what is it called?
Carl Linnaeus
Binomial naming system
What did Linnaeus realise?
Species could be clustered together into different groups;
He noticed that despite being levels of diversity, species also shared similarities and so must share a common ancestor!
What did Lyell study, how did this help prove Darwin’s theory?
Lyell studied stratification in rocks and used his knowledge in geology to conclude the earth 6000 years old but about 1million (he was wrong).
This gave Darwin’s theory of evolution enough time to work. As 6000 years wouldn’t have been long enough for all of the diverse species to evolve which walk to earth today.
What did Thomas Malthus publish?
(1766-1834)
Essay on the principle of population (1798)
Darwin shared his ideas with others and with readings, which encouraged his theory of evolution
What problems did Darwin encounter when wanting to publish his theory?
Creation myths! - these were generally accepted and religion was very powerful at the time.
Darwin was worried how people would react to his idea as it went against these creation myths and were not in-line with the bible
What made Darwin finally publish his work?
Others were publishing work with similar ideas!
WHO and why got the nickname “Darwin’s bulldog”
Thomas Huxley
He argued forcefully in public meetings with bishops and other sceptics for Darwin, against creation myths.
While Darwin himself, avoided the conflicts
True or False
Creation myths are no longer believed?
False!
Creation myths are still supported by some!
This is possibly due to religious reasons.
What other problems, despite creation myths, did Darwin face?
- Mechanism for heritability was unknown
(he knew breading could lead to change, but didn’t understand the mechanism of how this happened)
Only after Darwin died, did genetic research begin.
What is “Darwin with genetics” called?
(Genetic research to prove evidence for Darwin’s evolution theory)
Neo-Darwinism
Who was Gregor Mendel? (1822-84)
An Austrian monk, who showed that traits were heritable!
Classified as Neo-Darwinism
However is work was unnoticed in his lifetime, as no one read his work until after he has passed
Who is Ronald Fisher (1890-1962)?
Published: The Genetical Theory of Natural Selection (1930)
An English Statistician who worked for a research station on artificial breading of plants
Classed as Neo-Darwinism
James Watson and Francis Crick?
(Neo-Darwinism)
Discovered DNA structure in 1953
They noticed that the DNA is fundamental to how inheritance can work and allows replication!
In their paper they explain that they understand this finding would have a large impact on the understanding of heritability, as this, DNA, is how information is transferred and swapped body to body
Sewall Wright (1889-1988)?
(Neo-Darwinism)
Published: Evolution and the Genetics of Population (1968-1978)
He provided the bedrock for understanding on modern population genetics. And how populations move/grow
The modern view on evolution: George Williams
Identified the idea that animals and plants don’t evolve for the good of the species but for themselves.
It’s only successful if the organism reproduces - individuals compete against eachother
Selection acts on individuals within populations not on populations as a whole
The modern view on evolution: Richard Darwin
Published: The Selfish Gene
Stated selection acts at gene level not species/individual level.
‘Bodies are just the genes way of reproducing’
A useful tool for evolutionary theory but genes are grouped into ‘individual’ organisms
Who stated: ‘nothing in biology makes sense, except in the light of evolution’
Dobzhansky (1973)
list 7 ways of Evidence for evolution?
- direct experiment
- biogeography
- fossil record
- homology, vestigial structures and homoplasy
- embryology
- comparative behaviour and biochemistry
- hierarchical organisation if life
- direct evidence for evolution from experiments
What is a guppy? Where is it from?
Guppies are small fish native to South American pools and streams.
True or False
Female guppies are colourful and prefer to mate with non-colourful guppies
False!
Female guppies are not colourful, however male guppies can be both colourful and non-colourful, but female guppies prefer colourful males.
Therefore the colourful males have more reproductive success as consequence
True or False
Fertilisation of guppy eggs occur externally?
True!
When a female is fertile she sprays her eggs into the water, the male guppies then fertilise the eggs externally!
