M16L2 Modern Classification Systems

Open Ended

Why is it so difficult to define which organisms belong to which species?

Multiple Choice

This ________ species concept is based on the idea that species are unchanging, distinct, and natural types (in other words, based on physical characteristics)

• Biological

• Phylogenetic

• Typological

• Evolutionary

This typological species concept is based on the idea that species are unchanging, distinct, and natural types.

Multiple Choice

The _________ species concept defines a species as a group of organisms that is able to interbreed and produce fertile offspring in a natural setting.

• Morphological
• Biological

• Ecological

• Phylogenetic

Biological species concept

•It does not account for extinct species or species that reproduce asexually. Also, some species, such as wolves and dogs, are known to interbred.

•This is the species concept used throughout this unit.

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Multiple Choice

________ is the evolutionary history of a species.

• taxonomy
• morphology
• anatomy
• phylogeny

​•Phylogeny is the evolutionary history of a species.

Multiple Choice

The _________ species concept defines a species as a cluster of organisms that is distinct from other clusters and shows evidence of a pattern of ancestry and descent.

• phylogenetic
• ecological
• morphological
• biological

•This definition solves some of the problems of earlier concepts because it applies to extinct species and species that reproduce asexually.

•It also incorporates molecular data.

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​Phylogenetic Species Concept

Multiple Choice

_________ are inherited features that vary among species.

• Characters

• Attributes
• Qualities
• Systems

Anatomical (Structural) Similarities
Size, shape, color

​​Morphological Characters

​​Biochemical Characters

Similarities in DNA= shared ancestry

Multiple Choice

A ___________ is a model used to estimate the time it has taken for species to evolve from a common ancestor.

• evolutionary tree
• phylogenetic diagram
• molecular clock
• genetic sequence

Molecular clocks are used to compare DNA sequences between species. The more mutations present, the more time has passed.

•Mutation rates are affected by many factors, making molecular clocks difficult to read.​

Multiple Choice

___________ classifies organisms according to the order that they diverged from a common ancestor

• Taxonomy
• Ecology
• Biodiversity
• Cladistics

Multiple Choice

•A _________ is a branching diagram that represents a proposed phylogeny of a species or group.

• genetic diagram
• evolutionary chart
• species map
• cladogram

•A cladogram is a branching diagram that represents a proposed phylogeny of a species or group.
One branch of a cladogram is called a clade.

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Multiple Choice

A _________ structure is inherited from a common ancestor

• analogous
• vestigial
• convergent
• homologous

The more derived characteristics two groups share, the more recently the groups shared a common ancestor.

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​Cladograms/Phylogenetic Trees

•Darwin used an analogy of a tree to suggest that all species developed from one or a few species.

•The term tree of life was coined in the nineteenth century to describe a diagram showing all living organisms.