evolution
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Evolution. History of Evolution. Important Players. James Hutton. Published studies in 1785 Geologist Theory of Uniformity- the earth was created by the same forces that are in existence today (plate tectonics) - PowerPoint PPT PresentationTRANSCRIPT
There is no 'Great Plan" out there toconform with the evolutionary theory,just organisms struggling to pass theirgenes on to the next generation. That'sit."
Evolution
James Hutton Published studies in 1785 Geologist Theory of Uniformity- the earth was
created by the same forces that are in existence today (plate tectonics)
Before Hutton, world was thought to be 6000 years old and formed by catastrophic events, not geological ones
His research supported that the Earth to be millions of years old
Thomas Malthus Worked with human population
studies Observed that plants and
animals reproduce at a greater rate than their ability for survival, creating competition within a species
Important to Wallace and Darwin’s theory
Jean-Baptiste Lamarck
1809- 1st to develop a scientific theory of evolution known as Theory of inheritance of acquired characteristics:
Organisms developed new organs or modified old ones to meet environmental challenges
Working toward perfection- more complex, more perfectSelective use or disuse would alter the size or shape of organs or structures passed to offspring
Examples Larmarck Observed Long Neck giraffes - short neck
giraffes that strained to reach higher branches would grow longer necks
Fiddler crabs large claw (male) -developed one larger front claw because it used to claw often to attract mates and ward off predators
Lamarck’s Theory Proven to be False
Change DNA by usage of the structures (BOGUS! Mendel was not yet born so little was known about genetics). Think of body building and passing that on to your offspring
No extinction of species, just changed into other organisms
Lower order organisms were spontaneously created to fill the void (nothing was due to chance).
Alfred Wallace 1850’s Naturalist Developed a theory similar to
Darwin’s His essay to Darwin motivated
Darwin to publish the book, On the Origin of Species.
Charles Darwin
1830’s Known as the “Father of Evolution” Naturalist on the HMS Beagle (shipping
vessel) collecting specimens of flora and fauna and created detailed written observations
Inspired by the biological diversity of the Galapagos Islands
Voyage of the Beagle 5 year voyage began in 1831 Only 5 weeks spent on the
Galapagos Islands Found endemic species Saw variations of organisms on the
different islands (thought that this could be modification due to environment)
Evolution Terms Evolution – descent with modification /
changes over time
Adaptation – inherited characteristic that may increase organisms chance of survival
Speciation – formation of new species
Species – group of similar organisms that can breed in nature and reproduce fertile offspring.
Evolution Terms
Homologous Structures – similar structures found in different organisms that serve different functions
Analogous Structures – structures that are different in form but have the same function.
Evidence of Evolution Biochemistry – DNA and amino acids Embryological Development Fossil Record Morphology – form and structure of
organisms without consideration of function
Vestigial Organs - structure that no longer serves a useful function in an organism (ex. Human appendix)
Fossils Age of fossils can be determined by:
1. analyzing its position in the sedimentary layers
2. Radioactive dating
Why are brown beetles more prevalent in a
population?
Each of the 4 mechanisms will change the gene pool frequency
Natural Selection Process in which organisms with
favorable traits (traits well suited for their environment) are more likely to survive and reproduceSurvival of the Fittest or the “Sexiest”
Imagine that green beetles are easier for birds to spot (and hence, eat). Brown beetles are a little more likely to survive to produce offspring. They pass their genes for brown coloration on to their offspring. So in the next generation, brown beetles are more common than in the previous generation.
Mutation change in DNA sequence that
causes a variation in the offspring A mutation could cause parents with
genes for bright green coloration to have offspring with a gene for brown coloration. This would make the genes for brown beetles more frequent in the population.
Migration Some individuals from a population
of brown beetles might have joined a population of green beetles. That would make the genes for brown beetles more frequent in the green beetle population.
Genetic Drift “Pure chance” Imagine that in one generation, two
brown beetles happened to have four offspring survive to reproduce.
Several green beetles were killed when someone stepped on them and had no offspring.
Patterns of Evolution Founder Effect Speciation Punctuated equilibrium Adaptive/Divergent Radiation Convergent evolution Coevolution
Founder Effect Organisms become separated or
isolated and the gene frequency changes
Founding organisms arrived on different islands of the Galapagos and due to the different availability of food slowly changed the gene pool of the population.
Speciation Reproductive isolation causes new
species to form Types of Isolation:
Behavioral Geographic Temporal
Punctuated Equilibrium Pattern of evolution in which long
stable periods are interrupted by brief periods of more rapid change
Hardy-Weinburg Theory No movement in or out of the
population No mutations No natural selection forces
Evolution Terms Adaptive/Divergent
Radiation – process that causes a single species to evolve into new forms and eventually new species
Homologous Structures
Evolution Terms Convergent
Radiation process by which unrelated organisms come to resemble one another because of similar environment
Analogous structures Cactus and spurge are another example
of convergent evolution.