Download Evidence of Evolution by Natural Selection

Evidence of Evolution by Natural Selection
Evolution by natural selection is a scientific theory that explains how Earth’s vast _______________
developed in the _____, continues to develop in the _______ and will continue to develop in the _____.
Natural selection is a process by which _________________ over many generations as organisms with
_____________________ traits survive and __________, passing their traits to their offspring.
There is an abundance of evidence supporting the idea of natural selection:
Fossils
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Fossils in young layers are more __________ to organisms living today than fossils found in deeper
stratum
Fossils appear in __________________ order
Not all organisms appear at the ________________________
Transitional fossils show ______________ between groups of organism
Comparative Anatomy
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Similarities in the basic pattern of anatomy is evidence of ___________ from a common ancestor
(homologous vs analogous)
Vestigial Structures/Features
Vestigial features are those that are _________________ and/or
______________ structures that are homologous to a fully functioning
structure in closely related species. _______ organism that has been
studied in detail has vestigial organs including humans.
Examples: tailbone, appendix and goosebumps in humans; pelvic bone in
whales and some snakes; dewclaws on dogs and some other animals.
Embryology
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Related species have similar _____________ development
Examples: tails and gill slits in human embryos, arm buds on
snakes, hair and teeth in baleen whales
Geographical Distribution
Related species are more likely to be found in areas that are ________________ to each other rather
than are locations that are geographically ____________ but ______________________________.
Example: Cacti species - only found in the Americas, even though suitable habitats exist on other
continents. This would indicate that they have descended from a single common species and have not
been able to cross the ocean.
Island species
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Animals found on islands often _________________ animals found on the closes _____________.
Islands get _______________ by organisms that dispersed from the nearest mainland
Once on the island, the colonizing species is ________________ and may be faced with different
_________________ _______________
The colonizing species will then _________
differently from its relatives on the mainland
Example: no native amphibians or large land
mammals have ever been discovered on
remote ocean islands
Galapagos Islands
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13 varieties of land birds found nowhere else
on Earth and ALL are finches
Each variety is a result of descent with
modification from a common finch ancestor
which somehow reached the islands from
South America
Comparative Biochemistry
Living organisms are highly similar at the __________ level, suggesting that they have descended from
a common ancestor, which carried the information to make these molecules.
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All cells are made of the same basic types of organic compounds: ____________, ____________,
____________ and ________________________
In all organisms, organic reactions are controlled by ____________________
All proteins are made of the same ______________________
The major carbohydrate molecule of cells are six carbon sugars such as _____________ and its
polymers, like starch and cellulose
All cells carry out _________________ respiration - ___________________
All cells contain __________, which determines ____________ structure
The _______________________ is universal (human DNA has been incorporated into the DNA of
bacteria and animals)
All species, studied in detail, also have _____________ - genes that have undergone __________
and ____ ____________ code for a ________________________
Example: Mammals have about 1000 functioning olfactory receptor (OR) genes that code for the
receptors that detect airborne chemicals; dolphins, like all mammals, breathe though their noses,
but have no need for a sense of smell in the air. Dolphins do have these same 1000 genes, but only
about ______ of them are functional. Biologists suspect that after dolphins evolved an aquatic
lifestyle, their OR genes were of no value, so any mutations that made the genes dysfunctional
would have been __________ and _________________________, so over millions of years most
of the dolphins’ OR genes have become pseudogenes.