Intro to Animal Diversity PPT

Choanoflagellate

• earliest relative of animals

• single-celled protists

• collar of cytoplasmic tentacles

• colonial

• some special cell function

animals are:

1. multicellular

2. eukaryotes

3. no cell walls

4. heterotrophs

5. motile

6. as3xual/s3xual reproduction methods

• have extracellular matrix providing structural support

• cell junctions hold cells in place to implement communication

modes of nutrition of animals

• heterotrophs

1. suspension feeding

2. bulk

3. fluid

suspension feeding

filtering particles from surrounding water

bulk feeding

eating large food pieces

fluid feeding

sucking sap or animal body fluids

animal movement mechanisms

• muscle and nerve cells within tissues unique to animals

• locomotion

1. food acquiring

2. escape predators

3. find mates

• special sensory nervous system to create movement

reproduction and development

• animals mostly reproduce s3xually

  • small sperm uniting with egg producing zygote

  • internal ferilization

  • external fertilization

• some may produce as3xually

  • metamorphosis

internal fertilization

mechanical insertion

• terrestrial species

external fertilization

sperm fertilizes a female's eggs outside of the body

• aquatic or moist environments

metamorphosis

• developmental phenomenon in which animal changes from a juvenile to an adult form

  • tadpole —> frog

• reduces competition

• creates dispersal

multicellularity

even relatively simple types of animals such as sponges are multicellular, in contrast to the mostly single-celled eukaryotic microorganisms, called protists

heterotrophs

animals obtain food by eating other organisms or their products

• contrasts with plants and algae

10 characteristics of animals

1. multicellular

2. heterotrophs

3. no cell wall

4. nervous tissue

5. movement

6. s3xual reprod

7. extracellular matrix

8. cell junctions

9. hox genes

10. SSU rRNA

1. multicellularity

• eukaryotic

2. heterotrophs

obtain food by eating other ogranisms or their products

• contrasts with autotrophs

3. no cell walls

cells are flexible

4. nervous tissue

presence of a nervous system in most animals enables them to respond rapidly to environmental stimuli

5. movement

contain muscle systems which work with nervous system to allow them to move

6. s3xual reproduction

most animals reproduce s3xually with small mobile sperm and larger egg, created a fertilized egg/zygote

7. extracellular matrix

proteins (collagen) bind animal cells together to give added support and strength

8. characteristic cell junctions

anchoring, tight and gap junctions

9. hox genes

give instructions for patterning the body axis

10. SSU rRNA

animals have very similar genes that encode for the RNA of the small ribosomal subunit

history of animal life

• multicellular animals emerged at the end of the Proterozoic eon

• first animals were invertebrates

• sudden increase in animal diversity contributed the the Cambrian explosion

Cambrian period

• 540-490 mya

• warm and wet

• abrupt diversity of animal species

• marine invertebrates were present, along with others no longer existing

  • examples of arthropods and chordates

summary of cambrian (story)

Cambrian explosion was this huge diversification event that happened at the end of the Proterozoic eon. In this time, it was wet and marine invertebrates diversified into arthropods and chordates. There was an evolution of shells and an development of a skeleton layer contributing to this explosion of life

3 causes to the cambrain explosion

1. evolution of shells allowed animals to exploit new environments

2. increase in atmospheric and aquatic ocean levels allowed more complex body parts

   1. production of ozone layer helped UV radiation

3. evolutionary arms race between predators and prey

animal classification

• monophyletic animal kingdom

• 35 animal phyla

3 early lineages of animals

1. ctenophora - comb jellies

2. porifera - sponges

3. cnidaria - jellyfish

main innovation of the first animal evolutionary branch

gain of 2 germ layers = multicellularity = endo and ecto derms

ctenophora

• comb jellies

• main innovation = gain of mesoderm

• 1st to evolve

porifera / parazoa

• sponges

• main innovation = loss of germ layers

• tissue divergence

• no symmetry

cnidaria

• primative radial symmetry

• gain of 2 germ layers

primative radial symmetry

Central core, but over multiple divisions the species is relatively the same 

5 simple patterns of phylogeny

1. tissue development

2. body symmetry

3. body cavities

4. patterns of embryo development

5. segmentation

tissues

• most Metazoans (animals) process of development showed 2-3 layers forming tissues

• tissues are groups of similar differentiated cells specialized for particular functions

3 primary cell layers in embryos

1. endoderm

   1. innermost layer

   2. forms lining of gut (digestive)

2. ectoderm

   1. outermost layer

   2. forms external coverings and nervous system

3. mesoderm

   1. middle layer

   2. forms muscles of body wall and most other structures between gut and external covering

2 types of body plans

1. diploblastic

   1. based on 2 embryonic layers (endo and ecto derms)

2. triploblastic

   1. based on 3 identifiable germ layers (endo, meso, ecto)

2 types of symmetry

1. radial

   1. primative

   2. body parts arranged around central axis

2. bilateral

   1. mirror image along midline

   2. most animals

   3. leads to development of head

cephalization

development of a head

4 aspects to bilateral symmetry

1. dorsal - to spine

2. posterior - to back

3. anterior - to front

4. ventral - to belly

3 terms associated w/ bilateral symmetry

• Cephalization 

• Dorsal and ventral 

• Anteriro and posteriror 

3 lineages of coelom

1. flatworm

2. nematode

3. earthworm

flatworm

1. Acoelomate = improper body cavity  

2. Blue = ecto 

3. Red = medoderm  

4. Yellow = endoderm 

5. No fluid filled 

   1. Pink jelly solid derived from mesoderm --> no fluid caps coelom  

nematode

1. Pseudocoelomate = fake 

2. Appears to be a fluid filled cavity = not true cavity cause it doesn’t have mesoderm surrounding the cavity  

   1. Mesoderm only surrounding the blue, no the endoderm (yellow) 

earthworm

1. Coelomate  

2. Fluid filled  

3. Red mesodermal layer on inside of ecto and the outside of the endoderm 

4. Coelome is surrounded by mesoderm --> entirely, true filled fluid space 

acoelomate animals

• no body cavity

pseudocoelomate animals

• false

• cavity not completely surrounded by mesoderm

• example: roundworms

coelomate animals

• coelom - fluid filled body cavity entirely lined by mesoderm

• in vertebrates, this lining is the peritoneum (came from mesoderm)

• mesenteries surround inner organs (protective)

8 stage cell division from zygote, cleavage and gastrula

• This will keep diving by multiples of 8, until the hollow ball called the blastula is made 

• Blastula is hollow ball and then gastrulation occurs where inwards folding occurs  

• The inside yellow layer from gastrulation makes the endoderm  

• 2 layers – ecto, pushes into endoderm 

• Triploblastic – ecto, endo and mesoderm (mesoderm in red) 

cell division in Protostomes (worms and insects)

1. Blastopore in protostome, inward fold become the mouth = primary opening 

   • Some may develop an anus 

2. Spiral cleavage 

3. Determinate cleavage 

   • Development ends when the cleavage occurs, one cell /4 is removed 

cell division in deuterostomes

1. Deuterostomes have mouth and anus  

   • During development, blastopore becomes the anus  

   • Therefore, we have to have formed a second opening for the mouth  

   • Secondary = mouth, primary = anus 

2. Radial cleavage  

3. Indeterminate cleavage 

   • If you take ¼ cells, now you have a single cell that was originally part of 4, which can continue developing to create a normal embryo, and the leftover 3 can also continue to make a normal embryo 

   • I.e. identical twins 

protostomes

nervous system on ventral side of body and brain surrounds opening of digestive tract

• worm or insect

• nervous system on front side of body

Brain – anteriror end 

• Runs along gut  

deuterostomes

nervous system and brain are on dorsal side of the body

• neural system is on dorsal side (back)Brain – anterior end 

  • Attached to spinal cord which continues down 

3 factors to proto/deuterostome bodies

1. Gut 

   • runs down middle of animal in both 

2. Heart and blood vessels 

   • In deuterostome in ventral 

   • In protostome in dorsal 

3. Nervous  

   • In deuterostome in dorsal 

   • In protostome in ventral  

• Heart and nervous are inverse 

segmentation

body structure that repeats along an anterior posterior axis and itself has an anterior-posterior polarity

• annelid worms, lobsters, chordates

• segmentation commonly associated with movement

morphological traits used In classification

• past methods include presence or lack of coelom or body segmentation

• molecular data is better used in describing differences in animal structure

molecular views of animal diversity

• scientists now use molecular techniques to classify animals

• compare similar in DNA, RNA, and AA sequences

• Related organisms have less differences

6 lineages of invertebrates

1. ctenophores

2. porifera

3. radiata

^^ earliest evolved

1. lophotrochozoa

2. ecdysozoa

3. deuterostomia

Ctenophores

• comb jellies

• less 100 species

• cilia on surface for movement/propulsion

• 2 sticky tentacles without singing cells

  • used to capture prey and don’t sting

• Protostomes --> have a mouth --> have 2 anal pores (weird) --> efficient at feeding and can eat large prey --> consist of male and female reproductive parts

porifera

• sponges

• Multicellular 

• Asymmetrical 

• Pore bearers – many pores 

• 8000 species  

• Range in sizes (very small to very big) 

• Porifera phylum 

• Adult sessile, free-swimming larvae 

Sexuality of porifera

1. sexual

   1. hermaphrodites - make egg and sperm

2. asexual

   1. small fragment or bud may detach and form a new sponge

body plan of sponges

• Choanocytes along the lining of the sponge's hollow tube  

• Trap and eat small plankton coming in through pores of sponge 

2 forms of bodies

1. Polyps 

   • Mouth/anus above 

2. Medusas  

   • Mouth/anus below 

• Proteostomes  

Radiata

• true tissues

• sac-like body with one mouth acting as mouth and anus

• simple

• marine

• capture prey with stinging tentacles

• life cycle includes polyps, medusae or both

cnidarian body plan

• aboral (end) on top

• oral (anus and mouth) on bottom

• epidermis - ecto

• gastrodermis - endo

polyp body plan

• anus and mouth at the top

Lophotrochozoa

• mollusks, annelids, and several other phyla

• named for the lophophore (feeding tentacles) and trochophore larva

• flatworms don’t fit into the category

Ecdysozoa

• nematodes, arthopods and a few other minor phyla

• named for ecdysis

• members secrete an exoskeleton that must be shed and regrown as the animal increases in size

Bilateria

• protostomia

  • lophotrochozoa (lophos = crest; troch = wheel)

  • lophophore feeding structure in 3 phyla

  • trochophore type of larva in annelids and molluscs

• ecodysozoa

  • cuticle or external skeleton secreted and periodically molted

• deuterostomia

ecydsis

cuticle or external skeleton secreted and periodically molted

lophophore feeding structure

• ring of ciliated feeding tentacles

or

• develop from a trochophore or modified trochophore larva

flatworms: platyhelminthes

• freeliving or parasitic

• acoelomate

• 3 layers: endo, meso, ectoderms

endoderm

• digestive cavity with specialized cells

mesoderm

• muscles and reproductive organs

ectoderm

• ciliated epidermis, nervous system and excretory flame cell system

flatworms

• Cant see but detect light or darkness 

• If swimming upright it will see sunlight 

• If swimming upside down it will see darkness 

phylum rotifera

• ciliated crown (corona)

phylogenetic bryozoans and brachiopods

• lophophore - ciliary feeling device helping with gas exchange

• true coelom

• u-shaped alimentary canal

• answer located near the mouth but outside the lophophore

lophophores

1. phoronida - horseshoe worms

2. brachiopods - upper and lower values

3. bryozoan - moss animals

phylum bryozoa

• small colonial animals

• look like plants

• 4500

• each animal secreted and lives inside zoecium

• composed of chitin or calcium carbonate

phylum brachiopoda

• marine animal with 2 shells

• similar in appearance to clams

  • dorsal and ventral shells (top and bottom)

• attach to substrate with a muscular pedicle

• 300

phylum mollusca 4 classes

1. bivalvia

2. polyplacophora

3. gastropoda

4. cephalopoda

bivalvia

marine or freshwater - shell 2 halves - primary filter feeders with siphons

• clams, mussels, oysters, scallops

polyplacophora

marine, 8 plated shells

• chitons

gastropoda

marine, freshwater, coiled shells

• snails, slugs

cephalopoda

marine, predators, tentacles, absent shells, closed circulatory system

• octopus, squids

slugs, snails and squid

• fleshy bodies in hard shell

• head-foot

• visceral mass

• radula

• mantle

• internal or external fertilization

bivalvia clams, scallops, oysters

• hinged pair of shells, abductor muscles

cephalopoda, squid, octopus

marine predators, most intelligent, closed circulatory system

phylum Ecdysozoa

• cuticle providing support and protection

• allows colonialization of dry environments

• functions like an external skeleton and skin

• ecdysis

• metamorphosis

ecdysis

• molting of the cuticle to allow growth

nemantoda: round worms

• second largest animal phylum

• mostly microscopic

• feed on decaying organic matter or parasite plants or animals

• responsible for numerous parasitic diseases; elephantiasis, pinworm (itch), hookworm

classification of the coelom of a nematode

• pseudocoelomate

• lack mesoderm on outer wall of gut

phylum arthopoda

• artho = joint

• pod = foot

• includes 4 groups

• exoskeleton results in common rate of being fossilized

• greatest species success

phylum arthopoda

• segmented bodies with specialized appendages for feeding, locomotion and reproduction

• exoskeleton

exoskeleton

chitin held together with fats and waxes

protects, supports and helps prevent dehydration