The presence of ________ structures suggests that these similar structures are due to a common ancestor.
Fish, reptile, bird and mammal embryos look similar probably because they all developed from a _______ __________.
The _____ the number of differences in the amino acids in a protein present in two species, the more closely related they are.
______ structures are those body parts that are present in reduced form but no longer serve a useful purpose.
The best term for the hard inorganic parts of animal bodies that may remain or turn to rock, or imprints of plant and animal remains, is ______.
The method of dating fossils by comparing their positions in rock layers is called _______dating.
A group of interbreeding organism in a defined area is called a _________.
Less complex and older fossils will be found in the _____ layers of rock if the land is geologically stable.
To date the imprint of a leaf, for example, a scientist would use _________ __________ to date the rock in which the imprint is found.
a small population that is isolated can evolve more _______.
For speciation to occur, 2 populations must become __________ isolated.
The evolutionary history of a species is its _________.
______ is the study of the distribution of species around the world.
The fact that all living organisms use the same genetic code to make proteins is one ______ _________ evidence of evolution.
Rapidly changing climates favor extinctions followed by ____ speciation.
variations; artificial selection
When Spaniards brought horses to North America in the 1500's the Nez Perce and Palouse tribes began breeding the horses, choosing as parents the strongest, most durable, most colorful and gentlest. Within 200 years they had produced the breed known today as the Appaloosa. The traits of the horses were _________ within the population, and the process of _____ ______ produced the Appaloosa. (separate answers by semi colon)
Evolution shows how organisms/______ has changed over time.
According to _______'s theory of natural selection, organisms produce more organisms than can survive.
Variations between members of a species are caused by ____________ ________.
Homologous structures ___ have the same function.
A polar bear's white fur is an _________ that allows it to camouflage itself on the snow.
overproduction of offspring
An insect lays hundreds of eggs. only a few survive to reproductive age. This is an example of _________
many variations are heritable
Discussions about artificial selection by English farmers convinced Darwin that ____ ________ ___ _________.
The high frequency of the sickle-cell gene in American blacks resulted from the gene's tendency to _______ fitness in a malaria-infected environment.
Many of our food crops are a result of ______ _______ by selecting the plants to be cross-pollinated.
The struggle for obtaining plenty of food, water , and habitat is called ________.
they share a common ancestor
Since human and fish embryos both have pharyngeal slits in early development, this suggest that ____ _____ _ _______ _______.
Some finches of a species have longer beaks; some have shorter beaks. These are _________ in the species.
overproduction of offspring
The two factors that cause a struggle for existence are an ___________ __ __________ and limited natural resources.
variations; changing environment
The driving forces behind natural selection and the formation of new species are _______ and a _______ ____________. (separate with semi colon)
The Hardy Weinberg Theorum conditions describe a ___ ________ population.
Radiometric dating works by comparing the amount of ________ ___________ atoms to the amount of decay product atoms.
If all members of a population have an equal chance at breeding and passing on their genes to the next generation, then _______ _____ is occurring in the population.
The ear bone of reptiles is called a ______.
_____________ structures have a common function/_________. (separate answers with semi colon)