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Emma Jarvis

on 2 March 2015

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Transcript of Evolution


spontaneous generation as believed until a scientist named Francesco Redi cam along and disproved the theory. He placed raw meat in covered and non covered jars, knowing that flies would appear because of the meat. If spontaneous generation was to be proven correct then there would be maggots found on the meat of both the covered and uncovered jars. but, there were only maggots in the uncovered jar. Proving the in order for maggots to be produced there needs to be other flies preasent to produce them. this is known as the theory of biogenesis
The first steps of evolution
Forms of Evolution
Biogenesis Vs. spontaneous generation
spontaneous generation
people believed that species just appeared out of thin air and that there was no further scientific explanation to how organisms came to be, they simply were there because they appeared. this was called
spontaneous generation.
for example people used to think that mice just appeared in bags of grain. they thought that grain was what generated the species
Microspheres and Coacervates
Endosymbiosis, like microspheres and coacervates helped to give way to life. Through creating organelles in cells. Endosymbiosis has made processes like photosynthesis and aerobic respiration possible.

-The most primitive cellular forms of life in the origins of life on earth.

Microspheres and coacervates both have the ability to form spontaneously and share many cell like properties. Because of this many scientists believe that microspheres and coacervates may be the bridge between non-living chemical compounds and cellular life. therefore, microspheres and coacervates are what started life on earth and evolution.

Convergent Evolution
Divergent Evolution
Adaption & Adaptive Evolution

Sexual Selection
Stabilizing Selection
& Fitness.
Disruptive Selection
Directional selection
The process of larger primitive cells engulfing smaller primitive cells to increase efficiency and productivity. Ultimately creating organelles in cells
The development of new organisms through pre-existing ones through time.
Thanks microspheres & coacervates!
-When different species evolve similar traits
an example of convergent evolution is the platypus. this semi-aquatic egg laying mammal, is actually poisonous. Platypus venom is closely related to snake venom. A-latrotoxin, found in the poisonous black widow spider was also found in the platypus venom
-The process in which descendants of a single ancestor diversify into species that fit different parts of the environment.
Darwins finches prove the idea of divergent evolution. While Darwin was visiting the Galapagos islands he saw many finches. but there were many different beaks that the finches had.there were finches with short strong beaks for cracking nuts and finches with longer thinner beaks for eating insects . All of the birds were finches, but their beaks were changed in order to suit the finch for its environment.
Adaption is
Adaptive evolution is evolving by adapting to the environment.
-Different species adapting to each others change.
- selecting a mate based on a sexual trait
stabilizing selection
is the process of keeping a trait average to the expectancy of that organism
is the measure of an organisms heredity contribution to the next generation

- Individuals with either extreme variation of a trait have a greater fitness than individuals with the average form of the trait.
- Individuals that display a more extreme form of a trait have greater fitness than individuals with an average form of the trait.
Evolutionary structures
Homologous Structure
- Anatomical structures that occur in different species and that originated by heredity from a structure in the most recent common ancestor
Analogous Structure
- Organisms that have different structures that perform the same function
Vestigial Structures
-A structure with no function. It has evolved with the organism but there is no real use for it
Artificial Selection
-Breeding organisms to the ideal specifications ideal for their surroundings
Natural Selection
-When nature chooses the characteristics that are best fit for the environment. Organisms with these characteristics survive and reproduce
Evolution Under Isolation
Geographic Isolation
& Allopatric Speciation
-Geographic isolation is the separation of two populations of the same species by a physical barrier
Allopatric speciation occurs when a species arises as a result of geographic isolation

Reproductive Isolation
-Reproduction that can't happen from the same species in either pre-zygotic or post-zygotic isolation
Pre-zygotic Isolation
-A type of reproductive isolation that occurs before the formation of the zygote, therefore mating does not occur.
-A type of reproductive isolation that occurs after fertilization
Post-zygotic Isolation
Speciation &
Sympatric Speciation

is when a new species arises.
Sypatric Speciation
is the process in which, new species evolve from a single ancestral species inhabiting the same region.

Evolution concepts
-The branch of biology that deals with the form and structure of animals and plants
-The relationship of organisms by ancestry
Biological Species Concept
-A group of organisms that can reproduce together, but not with other groups.
For example- Humans mate with other humans and cats mate with other cats. Cats and humans cannot successfully mate each other.
Gradualism Vs. Punctuated Equilibrium
is the hypothesis that evolution proceeds chiefly by the accumulation of gradual change.

Punctuated equilibrium
is an evolutionary theory that a rapid change can create a change in the evolutionary chain
Evidence of Evolution
-The remains or traces of an organism that died long ago
One promenade example of a fossil is Tiktaalick, discovered in 2004 in the Canadian Arctic. This 375 million year old fossil is the bridge between land and sea animals. Tiktaalick had a functioning arm and was able to climb out of the water, starting the very first evolution of land animals
Relative Age Vs Absolute Age
-Relative age is the rock/fossils age compared to that of other fossils over a geological timeline

Absolute age is the scientific estimate of the real age of the rock/fossil
-This principal states that if the rock strata at a location have not been disturbed, the lowest stratum was formed before the strata above it.
the photo above demonstrated the main point superposition makes, the closer to the core the older it is, the further up from the core the newer
- The study of the locations of organisms around the world
watch 7:02-8:51
How We Trace Evolution
Population Genetics
-The study of genetics based off of a group rather than an individual.
Bell Curve
Statistics on a graph that form a bell shape trend. Most of the statistics lie heavily in the middle but there are always others that fall on the other sides.
Allele Frequency
-The percentage of a population that carries a specific gene
Phenotypic Frequency
-How often a particular trait appears in a group of organisms
Hardy Weinburgh Genetic Equilibrium
-Genotype frequencies tend to stay the same from gene to gene unless acted upon by an outside influence
this illustration breaks down the morphology of a bird
The diagram above explains the phylogeny between whales and four legged mammals
meaning that the organisms were able to successfully conceive, but the embryo was not able to grow to its full potential
As seen in the video, the male blue footed booby (the smaller bird) will spread his wings and stomp his feet to try to get the female to mate with him.
The Dogo Argentino is a perfect example of artificial selection. the Dogo Argentino was breed over generations in order to create the perfect boar hunting dog. The breeders put together dogs in order to get traits like a good sense of smell, high speed, cooperation with other dogs,fur color, and they even decided to make the Dogo Argentino have a gentle side and breed out the aggression that many of the Dogos ancestors had
All of the diagrams on the left are the same structure , but the arm of an alligator is very different than the arm of a human, because the two have very different functions
An example is the human nose and the antennae of bees. both are used by the organism to smell, but they are extremely different in structure
A vestigial structure that humans have is the pinky toe. Running, walking,skipping jumping, dancing and everything you cold possibly want to do, do not require the pinky toe.
Relative age goes by the rules of super position we know that the further down the rock layer is the older. But by finding items that archeologists have a rough age for can bring scientists closer to finding absolute age
pre-zygotic isolation could happen for many reasons, one of them could be due to mating ritual. A mating ritual like the dance of the blue footed booby that was previously touched upon. The male blue footed booby could perform this dance to a different kind of female bird and she may not understand or know how to properly respond. this would be an example of pre-zygotic isolation
this graph shows that due to the drastic differentiation of the colors on the shells the organism is
This picture shows that the birds favor the taste of green beetles and eventually lead the extinction of the green beetles. While the orange beetles flourishes because it is ignored by the birds
Robins usually lay four eggs. Laying more than four eggs could lead to the chicks starving but laying less than four could result in no viable offspring
This graph shows that anteaters with longer tongues have the advantage over anteaters with shorter tongues
an example of this is pure breads they all have similar traits that are passed amongst each other and will continue to pass down these traits until another dog comes into the mix and gives way to new traits.
Sometimes organisms simply cannot mechanically come together or there is a reason for the embryo not evolving once fertilization has occurred.
This picture depicts a change in the environment that has separated the species. now that the two organisms are separated geographically it is likely that they will go an off and mate with other organisms creating a new species
Giraffes are an example of adaptive evolution they have their long necks in order to reach their food source. The giraffes that have shorter necks and cannot reach their food die. And only the long neck giraffes prosper because they have a trait that makes them suitable for their environment.
An example of coevolutionis that between moths called Morgan's sphinx and a flower called Darwin's orchid. The flowers have long tubes that lead to their nectar. While the Morgan's sphinx have incredibly long tongues. The moths with short tongues could not reach the nectar of the Darwin's orchid. The flowers with shorter nectar tubes proved useless for pollination because the Morgan sphinx's tongue is so long that the moth would not be close enough for pollination. So over time the morgan's sphinx moths developed longer tongues and the Darwin's orchids developed longer nectar tubes.
Allele frequency is determined by dividing the number of certain allele by the total number of alleles of all types in a population

This picture shows that there was a split within the beetle species because the species diverged , there was not as much interbreeding with the original species, causing the beetles to evolve and pick up new traits creating a new species of beetle.
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