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31 Cards in this Set

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The Greek philosopher Plato claimed that every organism was an example of a perfect essence or type created by God and that these types were unchanging.
This kind of _________ __________ is based on the idea that species are unchanging types and that variations within species are unimportant
Typological thinking
Scientific theories usually consist of a natural pattern and a __________ the explains that pattern
Process
In 1858, Charles Darwin and Alfred Russel Wallace made the claim that _______ has occurred, that species have changed over time
Evolution
Then they proposed ________ ________ as a process to explain the pattern of evolution
Natural selection
Aristotle ordered the types of organisms into a linear scheme called the _______ _______ _ _______
The great chain of being
In this chain, species were organized into a _______ sequence based on increasing size and complexity, with humans at the top
Fixed
In 1809 Jean-Baptise de Lamarck proposed that simple organisms originate by spontaneous generation and then evolve by moving up the 'chain of being' over time.
Lamarck suggested that the process responsible for the pattern was the __________ ____ _________ _________
- Individuals change in response to the environment and then pass on those changes to their offspring
Inheritance of acquired characters
Darwin and Wallace proposed that change in species through time does not follow a linear, progressive pattern, but instead is based on ________ among individuals in a population
Variation
A __________ consists of individuals of the same species that are living in the same area at the same time
Population
This view utilizes _________ ________ rather than typological thinking
Population thinking
- They stated that variation among individuals in a population was the key to understanding the nature of species
Darwin described evolution as ________ ___ _________, meaning that change over time produced modern, modified species from ancestral species
Descent with modification
- In other words, ancient species are the ancestors of current species
The pattern component of the theory of evolution by natural selection makes two claims about the nature of species
1- Species change through time

2- Species are related by common ancestry
________ are traces of organisms that lived in the past. These traces can include bones, branches, shells, dung, tracks, etc.
Fossils
The many fossils that have been found and described in the scientific literature make up the _______ _________
Fossil record
Most fossils are found in _________ ________, which form from layers of sand, mud, or other minerals, with younger layers deposited on top of older layers
Sedimentary rocks
Layers of sedimentary rock are associated with different intervals in the ________ _____ ________ - a relative time scale based upon fossil content of young to old
Geologic time scale
Fossils provide evidence for ________ species, those that are no longer living
Extinct
Early scientists suggested that extinct fossil species are typically succeeded, in the same region by similar species.
- This pattern became known as the _____ ___ _________
Law of succession
As the fossil record improved, many fossils have been discovered that exhibit ________ __________, traits that are intermediate between earlier and later species
Transitional features (or transitional forms)
A ____________ _________ is a reduced or incompletely developed structure in an organism that has no function, but is clearly similar to functioning organs or structures in closely related species
Vestigial traits
________ _____ ___________ - not static,unchanging, and fixed types, as claimed by Plato, Aristotle and the theory of special creation
Species are dynamic
Darwin proposed that the mockingbirds were similar because they had descended from a common ancestor.
Mockingbirds species are part of a __________, a family tree of populations or species
Phylogeny
The relationship between different species can be shown on a _________ ______
Phylogenetic tree
__________ is a similarity that exists in species descended from a common ancestor
Homology
Homologies can be recognized and studied at 3 interacting levels
Genetic

Developmental

Structural
_________ __________ is a similarity in the DNA sequences of different species that are due to inheritance from a common ancestor
Genetic homology
___________ ___________ is a similarity in embryonic form that is seen in embryos of different species and is due to common inheritance from a common ancestor
Developmental homology
__________ ________ is a similarity in adult morphology. Also described as similarities in organisms' structures that are due to inheritance from a common ancestor
Structural homology
The three levels of homology interact: _______ homologies cause the __________ homologies observed in embryos, which ten lead to the _________ homologies recognized in adults
Genetic

Developmental

Structural
The most fundamental homology is the _______ ______
Genetic code
Nearly all living organisms use the same code for translating language of DNA into the language of proteins
Biologists have documented dozens of contemporary populations that are undergoing _________ - a process that results in one species splitting into two or more descendant species
Speciation