Flashcards in Introduction to Evolution Deck (89):
the progressive change of organisms as they descend from ancestral species-is a fact. By now, the evidence for it is overwhelming and ubiquitous
The existence of evolution has been proposed several times in history. For instance, an ancient Greek scientist that proposed a theory of evolution was named
When was evolution first advanced proposed
Late 1700s early 1880s
Name two reasons why evolution remained controversial for a long time
1) It ran contrary to contemporary religious ideas
2) No mechanism for evolution was known
The first plausible, widely accepted mechanism for evolutionary change by natural selection was proposed by....
Darwin and Wallace
Darwin and Wallace's theory of evolution is well tested and supported by hundreds of scientific investigations, are aspects of it falsifiable?
Yes, some have been successfully challenged and others supported, just like other mechanisms of evolution as well.
a retrovirus of enormous medical concern. Because of evolutionary studies, we know that two separate lineages of this retrovirus passed into the human population from African Apes in the mid 20th century.
This knowledge has alerted us to the danger of emergent diseases from other animal hosts, a reason for our concern about SARS and bird flu.
Our understanding of ______ enabled us to develop a therapy for HIV
By using three drugs simultaneously, we subvert the evolution of the virus…evolving resistance to one drug means loosing resistance to another. What is this method of HIV treatment called?
an evolutionary phenomenon of tremendous clinical significance involving medicine evolved by fungi (like penicillin) over millions of years to kill off their bacterial predators and resistance to it
Since the ____th century, the bacterial pathogens have evolved resistance to our antibiotics, because extensive use of these drugs has caused very strong natural selection in favor of mutations which favor antibiotic resistance.
Strains of this bacterial pathogen have evolved resistance to penicillins, tetracyclines, spectinomycin and floroquinolones.
Scientific understanding of evolution came out of its infancy in 1859, when theories of _____ by Charles Darwin and Alfred Russel Wallace became widely known
Evolution by natural selection .
We now know of other mechanisms of evolution, including ____ and ______, but natural selection is the only mechanism capable of producing adaptation.
Genetic Drift and Mutation
Was natural selection immediately accepted?
Which decade were Darwin's ideas synthesized with a modern understanding of genetics for widespread acceptance?
Linnaeus and Taxonomy
Malthus and the Principle of Population
Lyell and Uniformitarianism
Lamarck and the fist comprehensive theory of evolution
The Voyage of the Beagle
Wallace and Darwin
Intellectual Stepping stones to developing a theory of evolution
the branch of biology concerned with naming and classifying living things.
The Swedish Physician and Botanist that founded the science of taxonomy, he developed the two part system of binomial nomenclature used today
Carolus Linnaeus did not believe in evolution by descent, the taxonomic system suggests some mechanism by which different forms of life are related to each other as a series of diverging, heirarchial, branches.
an eighteenth century economist, published “An Essay on the Principle of Population” in 1798.
What two things did the essay on the principle of population imply?
People have more children than can possibly survive
Human populations are kept in check by famine, starvation, and disease
Darwin added what to Malthus's theory
EVERY species has more offspring than can be expected to survive
Why was Archbishop James Usher's calculation of the birthof the earth as 4040 BC based upon the Old Testament wrong?
It left little time for slow, gradual processes like evolution
When was the age of the Earth determined?
Did ideas vary greatly?
Geologist and physician that proposed that it was possible to explain geological land formations by processes that are currently in operation, like erosion and sedimentation
Canyons were cut by the erosion of streams, layers of sediment were deposited at the edge of river deltas, these processes occurred slowly over a very long time-this idea was called
uthe idea that geological processes in operation now operated similarly in the past, at about the same rate.
English geologist that was a contemporary of Darwin's who was a proponent of Hutton's and went a bit farther by proposing uniformitarianism
developed the first comprehensive model of evolution, a French Zoologist and curator of the invertabrae collection at the Paris museum
Jean Baptiste de Lamarck
Lamarck saw many different lines of descent among the fossil invertebrates he encountered: instead of Aristotle’s single scala natura, there were many.
He proposed that organisms increased in complexity through time because of an innate tendency
He proposed that interactions of organisms and environment drove the process of evolution.
Jean Baptiste de Lamarck
He followed the widely accepted notion that characteristics acquired during an individual’s lifetime could be passed to one’s offspring.
He proposed that patterns of use and disuse drove the evolution of adaptations. In stretching their necks to reach leaves high in the treetop, giraffes acquired slightly longer necks, and passed these longer necks to their offspring.
Jean Baptiste de Lamarck
According to him, every organism was continually striving for greater complexity, a clam strove to be a better clam, etc.
Jean Baptiste de Lamarck
Can Lamarckian evolution be disproved by experiment?
we now know that acquired characters cannot be passed to offspring, also, evolution carries no innate tendency toward increasing complexity, but Lamarck’s theory was an important prelude to Darwin’s, it opened the door to thinking that organisms can and do change over the course of time.
Much of Charles Darwin’s inspiration for his theory of evolution by natural selection came from his voyage on the HMS Beagle, in 1831.
He saw an incredible diversity of species, with adaptations to a wide variety of environments; Brazilian rainforests, Chilean deserts, oceanic islands, etc.
Which islands impressed him particularly because most of the species there live nowhere else in the world, yet their closest living relative is on the mainland a few hundred miles away.
a nineteenth century naturalist and explorer, an expert on collecting specimens for resale in Europe, developed essentially the same theory of evolution by natural selection as Darwin.
An active man, he sat down to write it recovering from a bout of malaria, when he was unable to go out and explore.
Alfred Russell Wallace
The two shared credit for the discovery, a rare example of diplomacy in 19th century science.
Darwin is better known today, because he amassed a considerable amount of evidence to support his ideas. Wallace’s arguments were more intuitive and contained a less-extensive battery of examples.
What did Darwin and Wallace's theories which had broad implications force European intellectuals to re-examine about their place in nature?
It removed the need of a divine prime mover
Evolution proposed a mechanism for the evolution of the human species its mind and achievements that is not supernatural
Darwin’s manuscript that contained several new ideas, ideas not found in earlier notions of evolution; published in 1859
The Origin of Species
The three tenets of the Origin of Species
All species evolve from earlier species
The mechanism is natural selection
Evolution occurs over a very long span of time
members of a species possessing more desirable traits will have more offspring and survive to reproductive maturity.
Did Darwin conclude that present day species have descended from a common ancestor?
Yes. No mechanism for speciation was proposed, however.
Is the gradual evolution of life on the planet and their descent from a common ancestor fact?
What does Darwin's theory of evolution explain, then?
How it occurred
What is a hallmark of a revolutionary scientific theory that applies to Darwin's theory of evolution?
It brings together many previously unexplained patterns under a single theory
List the 4 original evidences for evolution
Vestigial and Homologous Structures
The Fossil Record
Closely related species go through similar stages of development, although the adults may not resemble each other very closely.
For instance, all vertebrate embryos develop gill pouches at some stage, even though in many species, they are lost later. This is suggestive of a common origin for vertebrates.
Embryological development is often suggestive of evolution: birds have many developmental features in common with reptilian ancestors, land vertebrate embryos have many features suggestive of an aquatic existence (gill pouches, a notochord, blocks of segmented muscle
Many species retain structures that only make sense in light of their ancestry.
These structures are typically reduced and nonfunctional, but they are inherited from ancestors, in whom they were important to survival or reproduction
Vestigial structure of Mexican Tetra Fish
Vestigial structure of the brown kiwi
Vestigial structure of rubber boa
Eyes sockets w/ no eyes
Tiny wings (can't fly)
Tiny remnant hind limb, called a spur, on both sides (it's a snake)
structures that are similar in their fundamental layout and construction, although they may serve very different purposes.
the forelimbs of mammals are constructed from the same skeletal elements: The wings of a bat, a whale, a human, a dog, etc. all contain the same bones, despite their different uses.
What do homologous structures suggest?
Common Ancestry rather than design constructs species
This homologous structure in humans only makes sense when its original configuration in a fish-like early vertebrate is considered
The succession of forms in this clearly suggests that organisms change through time, and have descended from a common ancestor.
What is the general trend in the fossil records?
The simplest organisms appear the earliest in time
How was this a new idea?
It was thought that they were all created at the same time
What observation goes against the view that each species was specially created for a purpose?
Many forms have gone extinct
True/False: The fossil record shows us a perfect record of common descent from ancestor to ancestor
What does it allow us to do?
Observed attributes, formulate and test evolutionary hypotheses
For organisms with a very good fossil record, like the ammonoid molluscs, does the fossil record show patterns consistent with descent with modification AND a good deal of extinction?
Do fossils document the transition from aquatic to transitional tetrapods?
The fossil record confirms the aquatic origin of tetrapods, but refutes what view of evolution?
That is progressive or goal-directed
What vestigial structures do contemporary whales have that show transitional forms?
Vestigial Femur and Pelvis
What structures do the 38 million year old Basilosaurus isis fossils contain that probably didn't function in swimming, but may have been used as a grasping structure during copulation
Reduced Hind Limbs
What structures do the 50 million year old ambulocetus natans have?
Functional hind limbs that were probably used as paddles in swimming
The distribution of living plants and animals suggests that organisms diversify into the ecological niches available to them-and when geography blocks dispersal, similar adaptations occur in unrelated taxa occupying the same type of habitat
Darwin and Wallace both documented this pattern extensively
What two ways has the theory of evolution been furthered since Darwin's time?
Natural Selection has been quantified
It has been applied towards combating disease
The misuse of this chemical has been pivotal in the re-emergence of malaria as an important human pathogen. If the evolution of mosquitos and malaria pathogens had been taken into consideration, it might have been prevented
How does DDT affect nonresistan insects?
Strong selective pressure in favor of mutations that might lead to resistance
The mutation for DDT occurs naturally (not induced by DDT), what effect does the DDT resistance have on the insect?
Decreases fitness in the absence of DDT
What two types of adaptation likely occurred in the past that are likely the cause of the DDT adaptation?
Adaptation occurring when enzymes evolve that break down the pesticide
They evolved to move from inner, sprayed walls to outer, unsprayed walls. They evolved sensitivity and avoid the pesticide.
Observe graph on slide 40! DO IT
What must occur for natural for natural selection to be effective?
Did Darwin know how variation persists?
No, but he discussed it extensively
Who was a contemporary with that had a theory spreading at the time?
The theory of genetics at the time that suggested that useful adaptations would blend into the population and become diluted
The synthesis of Darwin's theory with Mendelian genetics led to our modern understanding of evolution, called
Thomas Hunt Morgan
Early 20th century evolutionary biologists widely credited with developing our modern understanding
Darwin's most important contribution as a mechanism of adaptation was
the only evolutionary mechanism that can produce adaptation (there are other forces, but not mechanisms that produce adaptation)
How can you observe that two fossils lived different lives?
They have bone structures designed for different functions (Think T-Rex arms vs others)