Categorii: Tot - selection - species - adaptation - isolation

realizată de Nada Amin 17 ani în urmă

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Darwin

Charles Darwin's theory of evolution posits that all species of life have descended over time from common ancestors through a process he called natural selection. This theory suggests that advantageous traits become more common in a population due to their contribution to an organism'

Darwin

Darwin & his theory of evolution

Relevance to origions of life

Geological evidence on both (biology & cosmology):
similarities between species that used to live in the certain region

but: as a result of erosions/volcano these animals were separated

supports the idea of life on earth being a result of several collisions & erosions (changes causing isolation >>differences)
no progress, just change

Misconceptions:

"Ladder of Progress"
it's a process of evolving & changes, not a progress

>>humans: not on top of the ladder

Incompatibility of religion & science (esp. evolution)
No! They don't deny each other

just 2 different topics

Evolution: neither observable> nor testable
it is testable; evidence: fossil record, study of living species (e.g. finches), artificial selection
Fossilization: incomplete process
Not really: complete enough to keep the theory going & prove it
D's theory: creation of universe
he focused on the development/changes after creation, not creation itself

Scientific Methodology:

Communicating with Wallace & other scientists
Evidence: reason therefore: isolation, adaptation of finches & genetic variation
Hypothesis: Variation of species due to natural selection & circumstances
Observation: variation of (species) finches during "Beagle" trip

Books & topics:




1881 - The formation of vegetable mould
1871 - The Descent of Man
1859 - Origin of Species > criticized because of missunderstood context
1854 - Baracles
1842 - The Structure & Distribution of coral reefs

Evidence

Comparative Morphology
Similarities in the structure of certain species & members of the same family

e.g.: dogs & dolphins (mammals)

Molecules
Genetic variation
Study of DNA: similarities in the material, most bases are the same
Embryology
suggests similarities between species
Fossil record:
anatomy; bones of dinasours

found in sedementary rocks

Theory of Evolution

Mechanism of Darwinian evolution: Heredity, variation, differencial reproduction
DNA: same form, different base sequence
Mendel's crossbreeding >> variation by time
transmission of advantageous features in new circumstances (mutation)
due to: competition, variation & environmental changes
(observing pigeons) variation of species by time
Isolation > Principle of Divergence
Natural Selection: survival of those inhabitants/creatures that fit best under the same circumstances
between & within species
Artificial Selection: deliberate effects on forms of domestical breeds
Man & apes all descended from a common ancestor, yet not the same

Most important landmarks

1858 - Wallace: pushed D. to publish his own writing
1798 - Malthus: principle of Population & controling it
1707 - Karl Linnaues: classification of living things ("texonomy")

Definition:

change over time
causing differences within species

Biography

1839 - married from a wealthy family > perfect environment for his researches
money & time to proceed with his research of nature
(1809 -1882)
(1831-36): on "The Beagle" ship around the world
significant for future observations on pigons > variation within species
1828: enters Christ College Cambridge > Theology