Speciation Flashcards

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1
Q

Define Speciation

A

The formation of new and distinct species in the course of evolution

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2
Q

Define Genetic isolation

A

Genetic isolation is population of organisms that has little genetic mixing with other organisms within the same species.

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3
Q

name two mechanisms that stop gene flow

A

Prezygotic isolation & Postzygotic isolation

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4
Q

Define Prezygotic isolation

A

the separation of different species to keep them from creating offspring by preventing the gametes from forming a zygote.

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5
Q

define Postzygotic isolation

A

occurs after members of two different species have mated and produced a zygote

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6
Q

define morphological species concept
give advantages and problems with it

A

Species identified based on differences in size, shape, or other morphological features
- Assumes morphological differences arise from genetic isolation

Advantages:
- easy, useful in the absence of data in gene flow
- can be used for fossils and asexuals

Problems:
-Polymorphic species can be classified as multiple species
-Hard to identify cryptic species

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7
Q

Define Monophyletic group

A

Consists of an ancestorial population and all its descendants. also called a clade or lineage

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8
Q

Define Synapomorphy

A

Homologous trait found in common ancestor and descendants but not in more distant ancestors.
a species is defined as the smallest monophyletic group on the tree of life

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9
Q

what is allopatric speciation

A

occurs when a species separates into two separate groups which are isolated from one another. A physical barrier, such as a mountain range or a waterway, makes it impossible for them to breed with one another.

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10
Q

Define Niche

A

Range of ecological resources that a species can use and a range of environmental conditions that it can tolerate.

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11
Q

Define Disruptive selection

A

Can cause reproductive isolation through populations adapting to different ecological niches

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12
Q

and are genetically distinct, hybrid offspring will have If two populations have diverged considerably _____ fitness

A

Lower

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