Animal diversity and relationships - Claremont Colleges

Animal diversity and relationships - Claremont Colleges

Animal diversity and relationships Living forms At least 30 phyla But only x important

ones Importance = numerous, ecologically important, and fit into

our conceptions of evolution Porifera = sponges

Assymetrical, 2 cell layers , internal silica spicules = skeleton. Cnideria, jellyfish, corals

Radially symmetrical, 2 cell layers, one ended digestive system. Often with algae inside to provide nourishment Light sensitivity.

Ctenophora comb jellies Bilateral, one ended gut, marine Platyhelminthes = flat worms. Three cell

layers, no body cavity, one ended digestive system, brain, nerves, many are parasitic. Two ended digestive system Head and tail, have an internal

cavity not solid. Very numerous in soil. Annelida = segmented worms; bigger most free living. Have nerves, three cell layers, true body cavity = coelom, circulatory system, excretory system. Skin breathing and many have legs. Some carnivorous, soil eaters

or leaches blood suckers Mollusca: clams, snails, squid, octopus, slugs Two ended gut, nerves, circulation, filter feeders or carnivorous. Some (squid, octopus)

with eyes, brain, etc. Remnants of segmentation chitins. Arthropods joint leg = insects, crustacea Segmented, brain, sense organs, excretory

system Echinoderms pentaradiate, Starfish, urchins, sea lillys.

Chordata, including vertebrata . Backboned organisms. The fossil record How to determine relationships try fossils first.

Burgess Shale in British Columbia, a unique preservation at the right age. Segmented worms (with legs?)

arthropods Chordate similar to early members of this group

sponge ???? Result of fossil record: all major groups plus some other odd ones appear almost simultaneously = no sequental appearance.

How to make sense out of diversity without fossils. Rules: simple to complex symmetry (assymetrical, radial, bilateral)

Cell layers 1 to 2 to 3 Embryology - (old ontogeny recapitulates phylogeny statement of Haeckel) Digestive system design; one ended to two ended

Ernst Haeckel, 1866; ontogeny recapitulates phylogeny = early stages of development mirror

evolutionary changes. Note gill clefts in all embryos, tail present, etc.

Basis; development is often incremental add new stages to old harder to change the beginning stages.

Classic example of this, the aortic arches in vertebrates. Start with a complete set;

need gill arches to deposit them. All embryos have gill clefts and a complete set of arches To get to adult stages, loose

some of the arches. Because of assymetry, doesnt fit into any neat story so viewed as a development separate from everything

else. Phylum porifera; sponges. assymetrical

Symmetry, bilateral or radial Radial symmetry plus one ended digestive system =

primitive Jellyfish, corals, radial cnideria

Bilateral symmetry; all other groups. Clues from development 1. Hollow ball of cells 2. Then 2 cell layers, one

opening,radial symmetry= cnidaria 3. Then three cell layers new opening bilateral symmetry = all higher forms Cell layers 2 vs 3. sponges and cnideria = 2

Digestive system one ended vs. two ended Flatworms bilaterial but with one openning to digestive system

Other worms two ended digestive system. So: 1 no symmetry, followed by radial and then bilateral - porifera oldest then cnidaria, then everything else 2. one ended gut, followed by 2 ended.

3. 2 cell layers, followed by three Now what? Use embryology the great Protostome Deuterostome split

Protostomes vs deuterostomes

First opening = mouth Determinate clevage Spiral clevage

Mesoderm = 4d cell Schizocoel coelom

First opening = anus

Indeterminate clevage Radial clevage Mesoderm = infolding Endocoel coelom Protostomes how to organize

Classical method mesoderm solid to pseudocoelom to true coelom one ended gut to two ended no segments to segments

Body cavity (coelom) in relation to mesoderm Solid mesoderm = no coelom = flatworms acoelomate Coelom partially lined with mesoderm =

roundworms pseudocoele Coelom completely lines with mesoderm = Segmented worms, vertebrates, etc. true coelom

Result = Molluscs = chitin, segmented. Odd legs?? Arthropods trilobite = segmented and

legs Seg. Worms (annelids) segments true coelom Round worms; two openings dig system pseudocoel

Flatworms one opening dig system, solid (acoelomate) Trilobite = arthropoda Chitin = mollusca Marine worm = annelida

All segmented. Deuterostome, protostome split Protostomes groups by

segmentation. Link segmentation together Note: Classical classification

((its wrong)) New phylogeny Lophotrochozoans

Ecdysozoans Filter feeders Shell shedders

Two phylogenies: left based on hypothesized relationships, right based on Both genetic similarity and time. Right is correct in that all major groups appear almost simultaneously (brushpile evolution)

Note: flatworms,mollusc and annelid together// no arthropods Arthropods and round worms in this group. N

E X T Ecdysozoans

Shell shedders separate Central position of flatworms as ancestral. Question marks.

segmented How come the old phylogeny wrong?

1. Segmentation arose more than once not a unifying trait 2. Some organisms, especially parasites (flatworms, roundworms) may have gotten simpler in structure through time. 3. A poor choice of unifying characters.

Recently Viewed Presentations

  • 2011 AVID PPT Format

    2011 AVID PPT Format

    Definition of a Persuasive Essay Persuasive Essays May make claims based on opinions May not take opposing ideas into account Persuades by appealing to the audience's emotion or by relying on the character or credentials of the writer Argumentative Essays...
  • PowerPoint 3C - WordPress.com

    PowerPoint 3C - WordPress.com

    * Overview of Genesis Genesis is not intended to be read as a detailed, chronological account of history. Genesis is an account steeped in truth and meaning. Chapters 1-11 of Genesis contain stories known as primeval history, meaning they refer...
  • Molina Healthcare of South Carolina - Provider Services

    Molina Healthcare of South Carolina - Provider Services

    Expedited Authorization Decisions - For cases in which a Provider indicates, or MSC determines, following the standard time frame could seriously jeopardize the enrollee's life, health, or ability to attain, maintain, or regain maximum function, MSC will make an expedited...
  • Capital Budgeting - Pearson

    Capital Budgeting - Pearson

    Capital Budgeting Decisions ... rate of CCA is reduced by one-half in the year of acquisition Tax Shield From Capital Cost Allowance Tax shield is the amount of cash saved on income taxes due to the deductibility of capital cost...
  • Creative Programming - University of Georgia

    Creative Programming - University of Georgia

    University Housing Mission. University Housing provides comfortable, affordable and secure on-campus housing options in residential communities where the academic success and personal growth of residents are encouraged and supported.
  • Jesus Christ: God'S Revelation to The World

    Jesus Christ: God'S Revelation to The World

    JESUS CHRIST:GOD'S REVELATION TO THE WORLD. The Writing of the Pentateuch. Traditionally, Moses has been named the author of the Pentateuch. ... DEUTERONOMIST—emphasis on morality and the Law; highlights Moses' speeches. PRIESTLY—census lists, genealogies, numbers, dates, proper ways to ...
  • Rape Investigation Handbook: Second Edition

    Rape Investigation Handbook: Second Edition

    Noble Cause Corruption Noble cause corruption refers to corrupt or illegal acts committed by law enforcement in order to secure or maintain an arrest or conviction, or some other worthy end. Law enforcement must select between competing ethics.
  • Omeka Webpage: burger quest 2012

    Omeka Webpage: burger quest 2012

    OMEKA WEBPAGE: HAMBURGERS Kathleen Comeau Content & Collections This digital library chronicles a quest for the best hamburgers in New York City & beyond Each item will be collected using still digital photography The collections are based on a ranking...