Announcements:

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Announcements 1. Labs meet this week 2. Lab
manuals have been ordered 3. Some slides from
each lecture will be on the web 4. Study
questions will be posted after each lecture
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Prokaryotes
Eukaryotes
Metazoa
Protozoa
Heterotrophic
Autotrophic
Absorptive
Ingest/digest
Animalia
Monera
Fungi
Plantae
Protista
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What is an Animal ?

1. Animals are multicellular, heterotrophic,
   eukaryotes that ingest and digest their food.
2. Animals lack a cell wall.
3. Are capable of moving (during some point in their
   lives).
4. All animals have regulatory genes called Hox
   genes.

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• To date gt 1.5 million species of animals have
  been described by biologists
• 10, 000 new species are described each year
• Estimates of the total number of animal species
  are around 10 million.

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What is a Species?
Species Concepts 1. Typological species
concept species are distinct, unchanging
entities defined by unique, morphological
features. This concept has been abandoned by
biologists.
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Some Problems with the Typological Species Concept
It ignores evolution species are not
unchanging entities
1. Artificial selection artificial selection for
oil content in corn
High oil
Low oil
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Natural selection Trinidadian guppies
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Some Problems with the Typological Species Concept
Sexual Dimorphism the sexes differ
morphologically
female
male
Sailfin molly
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Some Problems with the Typological Species Concept
Alternative morphs
Hornless morph
Horned morph
e.g. horn polymorphisms in beetles
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Some Problems with the Typological Species Concept
Cline a change in in morphology along an
environmental gradient
Size in yarrow
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Some Problems with the Typological Species Concept
Drosophila subobscura
Latitude
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Some Problems with the Typological Species Concept
Cryptic species some species are similar
morphologically but differ in other important
ways
Western meadowlark
Eastern meadowlark
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What is a species?
Species Concepts 2. Biological species
concept a species is a population or group of
populations that can potentially interbreed and
produce viable,fertile offspring, but that is
reproductively isolated from other populations.
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There is tremendous morphological variation
within Homo sapiens. But all humans can
potentially interbreed. In contrast, some species
are very similar morphologically but can not
interbreed
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Western meadowlark
Eastern meadowlark
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• Mechanisms of reproductive isolation
• 1. Prezygotic barriers prevent mating or
  fertilization
• Behavioral

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Western meadowlark
Eastern meadowlark
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• Mechanisms of reproductive isolation
• 1. Prezygotic barriers prevent mating or
  fertilization
• Behavioral
• Temporal

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Western spotted skunk summer breeder
Eastern spotted skunk winter breeder
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• Mechanisms of reproductive isolation
• 1. Prezygotic barriers prevent mating or
  fertilization
• Behavioral
• Temporal
• Habitat isolation

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Aquatic garter snake
Terrestrial garter snake
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Mechanisms of reproductive isolation 1.
Prezygotic barriers prevent mating or
fertilization 2. Postzygotic barriers
prevent hybrid from developing into a viable,
fertile adult
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Some problems with the biological species concept

1. It is hard to apply especially to fossil data.
2. Species exist in time and space the biological
   species concept has no time component.
3. What do we do with asexual organisms?

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• Bdelloid Rotifers havent reproduced sexually for
  gt 80 million years- each individual is
  reproductively isolated !
• An estimated 2000 species are completely asexual.

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• Species Concepts
• Typological species concept
• Biological species concept
• Evolutionary species concept
• Incorporates time
• Ecological species concept
• Incoporates niche
• Phylogenetic species concept
• Incorporates unique, evolved traits

These have all been proposed to solve some of the
problems of the other concepts
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• To date gt 1.5 million species of animals have
  been described by biologists
• 10, 000 new species are described each year
• Estimates of the total number of animal species
  are around 10 million.
• How do biologists organize all of this diversity?

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Classification and Phylogeny of Animals

• Taxonomy the branch of biology that deals with
  the systematic classification and naming of
  species (or groups of species) (long
  pre-Darwinian history).

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Taxonomy

• Carolus Linnaeus (1707- 1778)
• Swedish botanist
• Systema Naturae a classification scheme that
  used morphology to group organisms into
  hierarchical categories

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Taxonomy
Linnaean Classification
Kingdom Phylum Class Order
Family Genus
species

• In this scheme the major categories are called
  taxa
• Higher taxa are increasingly inclusive
• Each species is given a unique binomial name
  Binomial nomenclature

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Taxonomy
Linnaean Classification an example
Kingdom Animalia Phylum Chordata
Class Aves Order Piciformes
Family Picidae Genus
Melanerpes species carolinus
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Taxonomy
Linnaean Classification another example
Kingdom Animalia Phylum Chordata
Class Aves Order Piciformes
Family Picidae Genus
Melanerpes species
erythrocephalus
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Taxonomy
Linnaean Classification another example
Kingdom Animalia Phylum Chordata
Class Aves Order Piciformes
Family Ramphastidae Genus
Ramphastos species sulfuratus
Keeled toucan
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Taxonomy
Linnaean Classification
Kingdom Animalia Phylum Chordata
Subphylum Vertebrata Class Mammalia
Subclass Eutheria Order
Primates Suborder
Anthropoidea Family Pongidae
Subfamily
Genus Gorilla
species gorilla
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Classification and Phylogeny of Animals

• Taxonomy the branch of biology that deals with
  the systematic classification and naming of
  species (or groups of species) (long
  pre-Darwinian history).
• Systematics the branch of biology that seeks to
  understand the evolutionary relationships between
  groups of organisms (post-Darwinian).
• -One of the major goals of systematics is the
  construction of phylogenies

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Systematics

• Phylogeny an evolutionary tree that depicts the
  relationships between living and extinct species
  (or higher taxonomic groups)

A
C
B
D
Most recent common ancestor of C and D
Most recent common ancestor of A and B
Most recent common ancestor of A, B, C and D
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Systematics

• What kind of information is used to construct
  phylogenies?
• Characters organismal features that vary among
  species (morphological or molecular
  characteristics)

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• Morphological characters used to construct
  phylogenies-
• Levels of organization
• 1. Cellular level an aggregation of cells
  that are functionally differentiated, but that
  are not organized into tissues
• 2. Tissue level cells are organized into
  tissues that have a specific function
• 3. Organ level tissues are aggregated into
  organs that have specialized functions

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jellyfish, corals, etc.
other animals
sponges
organ level
tissue level
cellularlevel
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• Morphological characters used to construct
  phylogenies
• Type of symmetry the arrangement of body
  structures relative to some axis of the body
• 1. Asymmetrical
• 2. Radial symmetry
• 3. Bilateral symmetry

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Asymmetrical
No plane can divide the body into two symmetrical
halves
Bilateral
Radial
gt 1 plane can divide the body into two
symmetrical halves
1 plane divides the body into two symmetrical
halves
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jellyfish, corals, etc.
other animals
sponges
bilateral symmetry
radial symmetry
asymmetrical
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• Characters used to construct phylogenies
• The presence of different body structures
• Developmental patterns
• Molecular data DNA / RNA sequence data

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• What kind of information is used to establish
  these relationships?
• Characters organismal features that vary among
  species (morphological or molecular
  characteristics)
• Homologous characters characters that are
  similar to one another due to shared ancestry
  (not necessarily shared function)

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Examples of homologous characters Vertebrate
forelimbs
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• Analogous characters characters that are similar
  to one another in function, but not ancestry.
• Analogous characters are not useful in
  determining the evolutionary relationships
  between organisms.

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Examples of analogous characters bat wings and
insect wings
Fly wing
Bat wing
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Classification and Phylogeny of Animals

• Taxonomy the branch of biology that deals with
  the systematic classification and naming of
  species (or groups of species) (long
  pre-Darwinian history).
• Systematics the branch of biology that seeks to
  understand the evolutionary relationships between
  groups of organisms (post-Darwinian).