# Chapter 32 & 33

## Kingdom Animilia

- Over 1.5 million species 
    - Estimated 73 million
- 35 Phylums 
    - Over half are insects
- More similarities within animal genomes than other kingdoms

### Characteristics 

- Multicellular
- Lack of cell wall
- Sexual reproduction 
    - mobile sperm
    - larger non-motile egg
- Nervous Tissue 
    - Complexity
    - Responsiveness
- Hox Genes 
    - Special clusters of genes associated with the planning of the body

[![Screenshot-from-2019-01-29-12-00-54.png](https://bookstack.aronwk.com/uploads/images/gallery/2019-01-Jan/scaled-840-0/7svEQ3Ey5pguUaDH-Screenshot-from-2019-01-29-12-00-54.png)](https://bookstack.aronwk.com/uploads/images/gallery/2019-01-Jan/7svEQ3Ey5pguUaDH-Screenshot-from-2019-01-29-12-00-54.png)

[![Screenshot-from-2019-01-29-12-01-51.png](https://bookstack.aronwk.com/uploads/images/gallery/2019-01-Jan/scaled-840-0/n9phZd3dW5Xva89B-Screenshot-from-2019-01-29-12-01-51.png)](https://bookstack.aronwk.com/uploads/images/gallery/2019-01-Jan/n9phZd3dW5Xva89B-Screenshot-from-2019-01-29-12-01-51.png)

### Metazoans

- All animals
- Multicellular animals
- Paratoans 
    - Sponges
- Eumetazoans 
    - "true" multicellular animals

### Classification/Systematics

- Old 
    - Morphology
    - Embryonic Development
- Recent 
    - Molecular genetics

### Body Plans

Morphological and Developmental Features

1. Body Symmetry
2. Number of tissue Layers
3. Patterns of Embryonic development

#### Symmetry

- Eumetazoa 
    - Divided by symmetry
- Radiata 
    - Radial symmetry
    - Often Circular or tubular
- Bilateria 
    - Bilateral symmetry
    - Dorsal 
        - Back
    - Ventral 
        - Front
    - Anterior
    - Posterior
    - cephalization 
        - enlarged head

[![Screenshot-from-2019-01-29-12-02-37.png](https://bookstack.aronwk.com/uploads/images/gallery/2019-01-Jan/scaled-840-0/uWhuBNwMH0OUgRwt-Screenshot-from-2019-01-29-12-02-37.png)](https://bookstack.aronwk.com/uploads/images/gallery/2019-01-Jan/uWhuBNwMH0OUgRwt-Screenshot-from-2019-01-29-12-02-37.png)

#### Tissues

- Metazoa 
    - all animals
    - divided on weather or not they have specialized tissues
- Parazoa 
    - Porfera 
        - sponges
        - may have distinct cell types
- Enmetazoa 
    - more than one type of tissue
    - organs
    - all other animals

##### Germ Layers

- Radial 
    - 2 layers
    - Diploblastic 
        - endoderm
        - ectoderm
- Bilateral 
    - 3 layers
    - Triploblastic 
        - endoderm
        - ectoderm
        - mesoderm

[![Screenshot-from-2019-01-29-12-03-02.png](https://bookstack.aronwk.com/uploads/images/gallery/2019-01-Jan/scaled-840-0/TFAhXfNlpGDLXT1R-Screenshot-from-2019-01-29-12-03-02.png)](https://bookstack.aronwk.com/uploads/images/gallery/2019-01-Jan/TFAhXfNlpGDLXT1R-Screenshot-from-2019-01-29-12-03-02.png)

##### Embryonic Development

- Protostome 
    - Blastopore becomes mouth
    - cleavage is determinate 
        - fate of embryonic cells are determined early
- Deuterostome (second opening) 
    - Blastopore becomes anus
    - cleavage is indeterminate
    - each cell produced by early cleavage can develop into a complete embryo

##### Other Morphological Characteristics

Used in classification

- Presence or absence or coelom
- Body segmentation

Molecular data suggest these features are unreliable in terms of understanding evolutionary history

##### Body Cavity

Coelom

- - a fluid-filled body cavity
- Coelomate or eucolemate 
    - true coelom
    - coelom completely lined with mesoderm
- Pseudocoelom 
    - coelom only partially lined with mesoderm
    - rotifers and roundworms
- Acoelomate 
    - lack of a body cavity and instead have mesenchyme
    - flatworms

[![Screenshot-from-2019-01-29-11-49-49.png](https://bookstack.aronwk.com/uploads/images/gallery/2019-01-Jan/scaled-840-0/Ll8Gw0R3zNLygxCm-Screenshot-from-2019-01-29-11-49-49.png)](https://bookstack.aronwk.com/uploads/images/gallery/2019-01-Jan/Ll8Gw0R3zNLygxCm-Screenshot-from-2019-01-29-11-49-49.png)

Flatworm has no mesoderm

Functions of the Coelom

- Cushions internal organs
- Enables movements and growth of internal organs independent of the body wall
- Fluid acts as a simple circulatory system

Segmentation

- Body may be divided into regions called segments
- occurs in annelid worms, arthropods, and chordates
- allows specialization of body region

[![Screenshot-from-2019-01-29-11-48-35.png](https://bookstack.aronwk.com/uploads/images/gallery/2019-01-Jan/scaled-840-0/8QttkWqKBKBu56Iy-Screenshot-from-2019-01-29-11-48-35.png)](https://bookstack.aronwk.com/uploads/images/gallery/2019-01-Jan/8QttkWqKBKBu56Iy-Screenshot-from-2019-01-29-11-48-35.png)

DO NOT worry about the number of species

## Molecular views of Animal Diversity

- Scientist now use molecular techniques to classify animals 
    - Compare similarities in DNA, rRNA, and Amino Acids
    - Closely related organisms have fewer differences than those more distantly related
- Advantages over morphological data in that genetic sequences are easier to quantify and compare 
    - Example: A,T,G, and C in DNA

### Genes used in Molecular Systematics

- Studies often focus on ribosomal RNA (rRNA) 
    - Universal in all organisms
    - changes slowly over time
- Hox genes also studied often 
    - Found in all animals
    - duplications in these genes may have led to evolution of body form
- Phylogenies constructed using rRNA and Hox genes are similar and often agree with those based on morphology

## Invertebrates

- "without backbone"
- +95% of all species

### Phylum Porifera

- Sponges
- lack tissues (organs)
- multicellular
- pores 
    - filter H2O and food
- Invertebrates

### Phylum Cnidaria

- Jelly fish, corals, anemones
- Diploblastic development 
    - Two tissue layers
- Mesoclea 
    - gelatinous covering
- Nerve net 
    - interconnected nerve cells
    - no brain
- One opening with gastrovascular cavity
- Protostomes
- Invertebrates
- Radial symmetry
- Salt and fresh water
- Stingers

### Phylum Ctenophora

- Comb jellies
- Same characteristics as Cnidaria
- Strictly salt water
- No Stingers

### Phylum Platyhelminthes

- Flatworms, tapeworms, flukes
- Triploblastic
- Organs and organ systems
- Enhanced nerve net 
    - 2 cerebral ganglia
- One opening with gastrovascular cavity
- Protostomes
- invertebrates
- bilateral symmetry
- Acoelomate

### Phylum Rotifera

- rotifers
- pseudocoelomate
- Triploblastic
- Two openings 
    - complete gut tract
    - alimentary canal
- Protostomes
- Corona
- simple brain
- invertebrates

### Phylum Mollusea

- Snails, slugs, oysters, octopus, squid, clams, muscles
- Triploblastic
- Eucoelomate
- Complete gut tract
- Protostomes
- Invertebrates
- Three part Body 
    - Foot
    - Visceral mass
    - Mantle 
        - Many have outer shells

### Phylum Annelida

- Segmented ring worms
- Triploblastic
- Eucoelomate
- Complete gut tract
- Protostomes
- Enhanced nervous system
- Invertebrates

### Phylum Nematoda

- Roundworms
- Triploblastic
- Pseudocoelomate
- Complete gut tract
- Protostomes
- Invertebrates

### Phylum Anthropoda

- Insects, crustaceans, spiders, ticks
- Highest diversity of animals 
    - >1.5 million species
- Hardened Exoskeleton
- Protostomes
- Invertebrates
- Eucoelomate
- Triploblastic
- Complete gut tract
- Enhanced nervous system 
    - Insects, in particular, have an enhanced brain
- segmented appendages

### Phylum Echinodermata

- sea stars, urchins, sea cucumbers, sand dollars
- Triploblastic
- Eucoelomate
- Complete gut tract
- Deuterostomes
- Simple nervous system
- Endoskeleton 
    - series of plates

## Phylum Chordata

- Deuterstomes
- Complete gut tract
- Endoskeleton
- Few invertebrates 
    - Mostly vertebrates
- Eucloemates
- Triploblastic

## Four Critical Innovations of Chordate Body Design

1. Notochord
2. Dorsal, hollow nerve cord
3. Pharyngeal gill pouches
4. Post-anal tail

- These four features are exhibited at some point of life history/development 
    - Only some Fishes exhibit all four

### Notochord

- Cartilaginous supporting rod along the dorsal axis
- Replaced by jointed "backbone" 
    - Vertebral column of hardened cartilage or bone

### Dorsal, hollow nerve cord

- Expanded at the anterior end 
    - Brian
- Enclosed/supported/protected by the Notochord

### Pharyngeal gill pouches

- Gill slits
- pharynx 
    - back of mouth cavity

### Post-anal Tail

- Tail extends posterior of the anus

#### Humans

##### Notochord

- replaced by vertebrae
- only pieces left are the inter-vertebral discs between vertebrae

##### Nerve cord

- Dorsal, hollow with largest brain capacity (compared to body size)

##### Pharyngeal Pouches

- Embryonic Development
- 1 pair retained as Eustachian tubes

##### Post-anal Tail

- One vertebra as a tail bone (coccyx)

### Subphylum Urochordata

- tunicates
- invertebrates
- ~3000 species
- Marine
- Filter feeders

[![Screenshot-from-2019-01-29-11-47-27.png](https://bookstack.aronwk.com/uploads/images/gallery/2019-01-Jan/scaled-840-0/inQ83f0n1DNhLdpF-Screenshot-from-2019-01-29-11-47-27.png)](https://bookstack.aronwk.com/uploads/images/gallery/2019-01-Jan/inQ83f0n1DNhLdpF-Screenshot-from-2019-01-29-11-47-27.png)

### Subphylum Cephalochordata

- Lancelets
- Invertebrates
- 25 species
- marine
- Filter feeders

[![Screenshot-from-2019-01-29-11-45-01.png](https://bookstack.aronwk.com/uploads/images/gallery/2019-01-Jan/scaled-840-0/Nuxg9xz3SwNgJgm8-Screenshot-from-2019-01-29-11-45-01.png)](https://bookstack.aronwk.com/uploads/images/gallery/2019-01-Jan/Nuxg9xz3SwNgJgm8-Screenshot-from-2019-01-29-11-45-01.png)