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Evolution and Classification - Evolution - Lecture Slides, Slides of Theory of Evolution

Evolution and Classification, Nested Classification, True Phylogeny, Study of Evolutionary History, Types of Taxonomy, Phenotypic Similarity, Branching by Speciation, Pattern of Anagenesis are the key important points of lecture slides of Evolution.

Typology: Slides

2012/2013

Uploaded on 01/02/2013

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Lecture 9: Evolution & Classification
Because of how evolution occurs:
Hierarchical, nested classification is natural
There is ONE TRUE PHYLOGENY
•Based on interrelationships
•Life started at one point & diverged
Origin
Speciation
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Lecture 9: Evolution & Classification

Because of how evolution occurs:

Hierarchical, nested classification is natural

There is ONE TRUE PHYLOGENY

  • Based on interrelationships
  • Life started at one point & diverged

Origin

Speciation

Study of Evolutionary History

  • Taxonomy: classification (naming)
  • Systematics: describes evol’nry relationships

Assume: similarity in heritable characters

signifies closeness of relationship

Use characters to deduce relationships & classify

Terminology

Evolution occurs in two ways:

1. Anagenesis: directional change in a lineage

2. Cladogenesis: branching by speciation

Rate & pattern of anagenesis + branching pattern

True Phylogeny

Reconstructing Phylogenies

Use:

1. Ancestral Character (Plesiomorph):

  • Primitive
  • Inherited with little or no change from ancestor

2. Derived Character (Apomorph)

  • Recently changed

Only CHARACTERS are PRIMITIVE, not SPECIES

Shared Characters

1. Ancestral Homologies

  • Character found in both taxa
  • Character found in common ancestor
  • Character not in all descendants

2. Derived Homologies

  • Character found in both taxa
  • Character found in common ancestor
  • Character in all descendants of common

ancestor

3. Analogies:

  • Characters have no common history
  • Characters are not in common ancestor
  • Characters developed independently

• CONVERGENCE

  • May be evolutionary reversals to ancestral

state

  • cause loss of info about relationships

More realistic example

abcdef abcdef abcdef abcdef abcdef

abcdef

a

b

c

d

e

f

a= ancestral

a= derived

Phylogenetic Groupings

1. Monophyletic

  • Shared derived homologies
  • Contains all the descendants of a common

ancestor

  • e.g. all birds

2. Paraphyletic

  • Shared ancestral homologies
  • Species with derived characters not included
  • Some but not all descendants of a common

ancestor

  • e.g. fish; reptiles – missing birds, mammals Docsity.com

Groupings

A A A A

A

A

A

A A A A

A

A

A

A A A A

A

A

A

Monophyletic Paraphyletic Polyphyletic

Phylogenetic Reconstruction:

Whales

  • Sea-dwelling ~ 53.5 mya
  • Descendants of Artiodactyla (even-toed

ungulates)

  • Rudimentary & vestigial characters

common to land mammals (pelvic girdle,

diaphragm, sensory structures)

  • Intermediary fossils: Ambulocetus – the

walking whale (47 mya)

  • Recent evidence:

hippos more

closely related to

whales than other

artiodactyla

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