Download File - Mr. Shanks` Class

Name: ________________________________
Date: _________________________________
On the Origins of Species +
The Modern Theory of Evolution
Natural Selection
The way in which nature ______________ the reproductive success of some individuals within a
___________over others
Some individuals would have a better chance of success than others
Ex. faster cheetahs would be more likely to catch __________ stronger male lion would be more likely to
__________ and mate with females
If this were true and these differences were ______________ then traits of favoured individuals would
become more common in the next________________- and these individuals would produce more offspring
Key is to favour __________________________success
Herbert Spencer vs. Darwin
Survival of the Fittest
A ____________that has been used to describe the process of natural selection
This phrase can be _____________________
An individual that lives a long life or has a strong _____________ appearance may be seen as physically
_________
But if the individual is unable to reproduce and pass on _____________ to the next generation according to
Darwin’s theory such individual would not be “fit”
As previously mentioned, natural selection lies in its ability to ______________ reproductive success
Adaptation
A characteristic or feature of a species that makes it well suited for ____________ or reproduce success in its
________________
Theory of evolution by natural selection can be extended to virtually every
_________________________________ or adaptation
* Darwin understood that with a diversity of environments, the process of natural selection acting over
thousands of generations could produce an unlimited _____________ of species *
Darwin’s Theory of Evolution
Prediction
Theory of natural selection enables scientists to make predictions about _______ species may change over
time, for example that species will evolve in response to _________________________ because different
environmental conditions will favour different traits
Testing and Falsification
To be a scientific theory it must have the potential to be _______________and testable to have the possibility
of being proven _______________
Summary
Darwin’s theory of evolution by means of natural selection explains how the environment acts to favour the
reproductive ___________________ of individuals with certain ________________traits over others
Darwin’s theory of evolution by means of natural selection is able to explain how an
_____________________ can arise
Darwin’s theory of evolution by means of natural selection can be used to make
____________________about the future evolution of species
Darwin’s theory of evolution by means of natural selection is a _______________ scientific ____________
The Modern Theory of Evolution
Name: ________________________________
Date: _________________________________
The Age of Earth
Until the twentieth C many believed Earth was less than __________years old and that species never changed
they just had always been present
Emerging sciences of paleontology and geology started to cast serious __________on the belief in a young
earth
Paleontology
The scientific investigation of prehistoric life through the study of ______________
Geology
The science that deals with the earth’s ___________________________and substance, its history and the
processes that act on it
Today’s evidence
Scientific consensus that Earth is more than _____billion years old and that the universe is approximately
__________billion years old
This evidence is largely a product of recent advances in ____________and understanding
Radiometric Dating
Radioisotopes
Atoms that undergo ___________________- An atom with an ____________nucleus that is capable of
undergoing radioactive decay
Paleontologists are able to use radioisotopes to obtain precise ______________of the ages of rocks
The nuclei of these atoms are unstable and release ______________particles changing from one form, the
parent isotope into another, the _________________ isotope
Radiometric Dating
Based on the ratio of parent isotopes in ______________________
Radioisotopes undergo decay in a very _______________way (half – life)
Half Life
The length of time required for half the _____________________of radioactive substance to undergo
decay… the half life is a _________________for any given isotope
The time it takes for exactly ________of a parent isotope to decay into a daughter isotope
The Modern Synthesis
The knowledge and understanding of genetics and other fields of biology have been combined with Darwin’s
theory of natural selection to form the __________________________________________________
Biologists define evolution as changes in the gene pool of a species over time
Gene Pool
The complete set of all ____________contained within a species or population
Individuals vary in their traits because they inherit different ________________of alleles
Natural selection acts to favour some genetic combinations over others
Mutations: The Source of Variations
Different individuals have different ______________________of the many alleles that are already present in
the ______________________
Sexual reproduction _____________________these alleles and produces an almost
____________________number of combinations
New or ___________________traits arise when new alleles and genes are produced by mutation and acted
upon by natural selection
Genetic Mutation
Change in _______
Name: ________________________________
Date: _________________________________
The bases that make up DNA may be switched or lost, and / or new bases may be ___________________
Mutation event can also result in an individual having _______________copies of genes
Duplication events are usually the result of _________________ during ____________________in meiosis
Crossing Over
The ______________________of chromosome segments between homologous pairs during synapsis
A ________________________________of the chromosomes during crossover causes an
________________exchange – transferring a portion of one chromosome to another and that
______________________ portion is likely to contain many genes
Gametes that receive a chromosome that is missing a section will have a ______chance of survival, while
gametes that receive a chromosome with duplicated genes are often _______________
Gene Duplication
Gene duplication is an important type of ________________ because it is a source of a new
_______________
The extra copy of the gene is free to mutate and may gain a new _______________
If a mutation in a gene results in a new _________________ that can no longer perform a vital function, the
organism may _______(even if it is beneficial in some other way)
But might result in the creation of a new and potentially _________________protein
The duplication and mutation of gene copies can result in entire ______________of closely related genes
The Effects of Mutations
Most mutations are neutral because they occur in non – coding portions of DNA and therefore produce no
visible change in an individual
Neutral Mutation
A mutation that does not result in any selective ________________or disadvantage
The environment does not favour or select ___________individuals with neutral mutations
____________________Mutation
Any mutation that increases that reproductive success of an organism
Relatively rare but are favoured by natural selection and accumulate in populations over time
Harmful Mutation
Any mutation that _____________________the reproductive success of an individual and is therefore
selected against
May make an organism less able to resist disease or avoid predators, or less ______________________at
obtaining food
Less successful at reproductive success and tend to ________________
Mutation Rates
Individual mutation rates are very difficult to estimate, but recent studies suggest that species with large
genomes are likely to have mutations averaging more than _______ per individual
Humans may average ________ or more mutations per individual (almost always neutral)
Human population carries over _____________genetic mutations
Relatively low for individuals but can be numerous in population overall
Duplication Mutations
Often ___________and so do not immediately benefit the individual, but provide a source of new genetic
material with the potential to evolve into new genes
Homologous Genes and Pseudogenes
Name: ________________________________
Date: _________________________________
Closely related species inherit ____________________genes
These genes inherited from a common ancestor mutate and _____________over time
Similarity between genes provides good evidence for the degree of __________species
More closely related two species are, the more similar we would expect their homologous genes to be
_________________
A _________________ gene that no longer codes for a __________________protein
Genes that have undergone mutations and no longer serve a useful purpose
Are found in virtually all species
Ex. human dysfunctional copy of the _____________ gene (necessary for production of vitamin C, but we
don’t need it because we normally produce adequate amounts of this in our diet)
Modern Paleontology
Distribution of fossils provided Darwin with important evidence for his theory of evolution
Today’s evidence
Human ancestors and primitive whales in Pakistan
Feathered __________________ in China
Fossils of dinosaurs in Canada
Until the 1960s, the locations of some fossils were quite puzzling, specifically when the discovery of fossils
of the same _____________in Africa, India and Antarctica (but _______________)
Today the study of biogeography has been complemented by great advances in the study of plate tectonics and
_________________________
Plate Tectonics
The scientific theory that describes the large scale _______________and features of earth’s crust (accounts
for many large surface features i.e. mountains, volcanoes)