Darwin and his theory of evolution
what's evolution
explains that what we see today is different from what existed in the past
Galaxies, stars, the solar system, and earth have changed through time, and so has life on earth.
It explains that living things share common ancestors.
Darwin called this process "descent with modification," and it remains a good definition of biological evolution today
darwin's misunderstandings
Evolution is a “ladder of progress”, a steady march of progress with organisms constantly getting better
Evolutionary theory is a theory about the origin of life.
fossil record is not complete shows evolutionary theory to be false
Because evolution is not observable or testable it is not science.
Evolution and religion are incompatible
Responses to his misunderstandings
Natural selection does weed out individuals unfit for a particular environment but conditions are changing
The origin of life is not the main focus of evolutionary theory but rather the way life changes after its origin
Fossilization is a very rare event. There must be specific conditions for a creature to be fossilized
Evolution is both observable and testable
the fossil record
Study of living species e.g. Darwin’s Finches
A rtificial selection in the laboratory
genetic mutation e.g. in fruit flies
in the scientific community there are thousands of scientists who are devoutly religious and also accept evolution
the importance of his voyage to galpage islands
he noticed different finches which helped him to develop his propositions
Darwin's propositions
Artificial selection has a marked effect on the domesticated plants and animals, although it is applied for a small number of generations
if a change occurs in the physical environment, individuals will be exposed to new circumstancesso individuals'll try to adapt
All species are characterised by variation between individuals
this will urge the tendency for varieties to be distinct successive generations
This PRINCIPLE OF DIVERGENCE is the most important factor in the evolution of new species
Species arose by COMMON DESCENT, as a result of DIVERGENCE from a COMMON STOCK
NATURAL SELECTION was the process by which new species were brought into existence
Darwin's book (the origin of species by natural selection)
there are differences betwwen offspring that survive and reproduce and those who don't
those who have heritable characteristics enable them to survive and pass those characteristics to their offspring
natural selection of varients explaned observations on the geography of species differences
what's the ultimate source of variations
mendal shows that organisims acquire traits through discrte units of heridity which later(genes)
the variations produced in these inherited traits is the raw material on which natural selection acts
evolution was seen to depend on genetic mutation and naturl selection