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Darwin's Theory of Evolution (Theory of Evolution :red_flag: (Species…
Darwin's Theory of Evolution
Theory of Evolution
:red_flag:
Natural Selection:
species naturally change over time, the environment(nature) selects individuals who use resources most efficiently to survive
Mutations in DNA:
change genes and produce variation in traits
Discovered heritable variations in traits were common in individuals within a species and variations occur by chance (studied by animal breeding, barnacles and other species)
sexual reproduction increases variety in offspring(Darwin's daughter)
Overproduction of Offspring
populations of all species have capacity to grow
species yjay produce more offspring survivr
For a population sizes to remain stable, many offspring must die
Survival
offspring that (by chance) has variation that adapt them to their environment would have greater chance to survive to maturity and to reproduce
Different survival and reproduction: cornerstone of natural selection
Species Change
individual organisms do not evolve, they have to mate sexually to produce offspring
through adaptation(occur through genetic change) many generations in one lineage of organisms result in new species
chance of variation, overproduction of offspring and differential survival and reproduction= proportion of individual w/ favorable phenotype will increase= a population adaptation to envoronment
Change accumulate and new species are formed, and natural selection is not directed or intentional
Natural selection vs. Inheritance of Acquires Characteristics (Lamarck)
: heritable variation, overproduction of offspring, differential survival and reproduction, species change(all provided by giraffes)
Present Arises From Past
evidence from Lyell geology study and Darwin studies around world
today's species are fixed, we are all share common ancester
Modification
Through Natural selection we see variations increase the chance that at least some individuals will survive if environment changes and how we are all related
Cloning: if we are all identical through cloning we will not service because here is no genetic variation
variation provides insurance not becoming an extinct species
Adaptation
Adaptation= logical cuz environment imposes limits on organisms, selcting against hose who are not "fit" and refer to every aspect of life and conects organisms to reasources in environment
if environment changes, adaptive value of some inherited characteristics also change(fat and salt)
Darwin's theory: all living species share common ancestor and natural selection explains how species change :star:
Darwin(1809-1882 in Russia)
:red_flag:
HMS Beagle (1831-1836)
marine fossils on mountains
found viona Indians
different animals(finches)
Theory(evolution by natural selction)
:star:
1) biological species don't stay the same through time
2) all life, biological speaking, takes a form of struggle to exist
3) natural selection- struggle culls out those organisms less well adapted to particular ecology
4) genetic variation produces increased livability are random
5) natural selection takes enormously long periods of time
Influences
Existence of fossils
Animal breeding(artificial selection)(change)
Thomas Malthus demographer (human population) human's reproductive ability is greater than the earth's resources
Geology, Charles Lyle proved that the Earth was enormously old
Lamarck's inheritance of acquired characteristics(France)
Grandfather, Erasmus believed that species could change over time
Influences on Darwin :red_flag:
Thomas Malthus
Influences Darwin's idea that individuals in a population compete for resources through his writing (An Essay on the Principle of Population in 1798-1826)
populations get checked by famine and disease
offspring who are "fit" have better chance to survive environment
Alfred Russel Wallace
Naturalist who worked in Malaysia had similar idea's to Darwin about evolution and natural selection :star:
Darwin completed his book fast dur=e to competition
Darwin= "The Origin of the Species" earns him greater share of recognition for the theory of evolution by natural selction
Charles Lyell
Believed that many small changes over long periods of time built today's landscapes and the Earth must be far older than most people believed
published book "Principles of Geology" (examples of idea)
Darwin studied his book during his Beagle Voyage
natural law ideas flourished in 19th century(God made laws= production of species)
Artificial Selection
Breeders of pigeons, dogs, and cattle inspired Darwin's ideas about selection
March 1855, Darwin becomes a pigeon fancier and set ups own breeding loft at home
Artificial Selection= Darwin's selective breeding
observations of how artificial selection worked helped him develop his concept of natural selection :star:
Jean Baptiste Lamarck
Early scientists to explore change in species and believed that an organism improve traits through increased use and then pass it to offspring
development of Inheritance Of Acquired Characteristics(Ex. Giraffes neck) >idea not supported by evidence
Barnicles (1846)
A type of sessile (non-motile) suspension feeding arthropod
attach permanently to hard substrates
study of barnacle= Darwin's most intensive study having took 8 years