9.10 Chapter 5 Study Guide(answer in Red)
Study Questions:
1. Biological Classification is based on physical similarities that reflect evolutionary
descent (Homologies). Two groups share a trait because they inherited it from a
common ancestor. But not all similarities are based on descent. Some arise as
adaptations to a common environment (Analogous similarities). It is necessary,
therefore, to separate out analogies from homologies.
● Define analogy.
Analogy refers to the comparison between the physical traits of different
animals to determine the basic blueprints of different organisms. Analogous
traits refer to characteristics that have similar appearance and function
between different groups, but do not originate from the same ancestry.
● Give an example of an analogous trait shared by two groups.
An example of an analogous trait shared by two groups is the dorsal fin in both
sharks and dolphins. The dorsal fins on the shark are analogous to the ones on a
dolphin since although the trait did not originate from a common ancestor, they have
a similar function.
● Are shared analogous similarities useful for classification? Why or why not?
Shared analogous similarities are useful for classification because the similarities
allow us to effectively differentiate and determine whether shared traits are inherited
from a common ancestor or not.
● Define homology
Homology refers to the degree of similarity as in physiology, structure or
development of varied species of organisms due to a common evolutionary
ancestor, although they might have different functions.
● Give an example of a homologous trait shared by two groups.
An example of a homologous trait shared by two groups is the similar bone
structures of a dolphin flipper and a human arm. This is because although the
functions of the structures, is different, they were inherited from the same
mammalian ancestor.
● Are shared homologous similarities useful for classification? Why or why
not?
Shared homologous similarities are useful for classification since the
similarities enable us to determine and differentiate whether different
structures are inherited from a common evolutionary ancestor or not.
Study Questions:
1. Biological Classification is based on physical similarities that reflect evolutionary
descent (Homologies). Two groups share a trait because they inherited it from a
common ancestor. But not all similarities are based on descent. Some arise as
adaptations to a common environment (Analogous similarities). It is necessary,
therefore, to separate out analogies from homologies.
● Define analogy.
Analogy refers to the comparison between the physical traits of different
animals to determine the basic blueprints of different organisms. Analogous
traits refer to characteristics that have similar appearance and function
between different groups, but do not originate from the same ancestry.
● Give an example of an analogous trait shared by two groups.
An example of an analogous trait shared by two groups is the dorsal fin in both
sharks and dolphins. The dorsal fins on the shark are analogous to the ones on a
dolphin since although the trait did not originate from a common ancestor, they have
a similar function.
● Are shared analogous similarities useful for classification? Why or why not?
Shared analogous similarities are useful for classification because the similarities
allow us to effectively differentiate and determine whether shared traits are inherited
from a common ancestor or not.
● Define homology
Homology refers to the degree of similarity as in physiology, structure or
development of varied species of organisms due to a common evolutionary
ancestor, although they might have different functions.
● Give an example of a homologous trait shared by two groups.
An example of a homologous trait shared by two groups is the similar bone
structures of a dolphin flipper and a human arm. This is because although the
functions of the structures, is different, they were inherited from the same
mammalian ancestor.
● Are shared homologous similarities useful for classification? Why or why
not?
Shared homologous similarities are useful for classification since the
similarities enable us to determine and differentiate whether different
structures are inherited from a common evolutionary ancestor or not.
