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Chapter 32-34: Animal Diversity
Objectives
1.
2.
3.
4.
5.
Define common characteristics amongst all animals
Animals can be characterized by “body plans”
Molecular data is providing new data for phylogeny
Understand life without a backbone
Understand life with a backbone
What does it mean to be an animal?
-Animals get food by;
1. Ingesting - Differs from absorption (Fungus)
2. Rely on other organism for food or are heterotrophic unlike plants
-Animals are multicellular unlike protists
1. Specialized cells (nervous and muscular are not found in any other multicellular organism
2. Cells are held together by proteins (mostly collagen which is only found in animals)
-Reproduction is mostly sexual with the 2n version dominating life
-Development into layers - leads to organs and tissue
-Some development includes a larval stage -sexually immature stage and undergoes metamorphosis
-Use of Homeoboxes or gene regulatory genes are common to all animals - many have similar DNA
sequences
Body Plan: Set of morphological and developmental traits that work together as a
whole.
*Research suggests gastrulation has remained unchanged for 500 million years but other aspects of
body plans have changed.
1.
2.
3.
Symmetty
Asymmetry = Sponges
tissues by
Radial Symmetry
Bilateral Symmetry
-Dorsal
-Ventral
-Anterior
-Posterior
-Cephalization
Tissue
*Specialized cells isolated from other
membranes (Called Germ layers during
development)
1.
2.
3.
Ectoderm = Surface of embryo = becomes outer
covering and nervous system
Endoderm = Inner surface = becomes inner wall of
organs and digestive tract.
Mesoderm = middle layer = becomes other
organs and muscles between the digestive tract
and outer layer
-Organisms that only have endo and ecto are considered
diploplasts
-Organisms that have all three are considered triploblasts
**All bilaterally symmetrical
Body Cavities of Triploblasts
-Coeloms prevent injury to
organs
-Allow organs to move and grow
indpendently of outer shell
-Humans are ?????
Determinate Cleavage means
cells are differentiated very early.
Ex. Take one cell out and the organism
will develop missing many parts and
inviable
Cells retain ability to turn into
any type of cell
Ex. Identical Twins in humans
Points of agreement of the two:
1.
2.
3.
4.
5.
Kingdom is Monophyletic and all animals
share a common ancestor
Sponges branch from the base of both
Clade opposite of Sponges (Eumetazoa)
includes organisms with true tissue
Most animals are in the Bilateria clade
Chordates are Deuterostomes
Morphological and
Developmental
Phylogenetic Tree
Molecular Data
Phylogenetic Tree
Invertebrates: No Backbone
1.
2.
Sponges lack true
tissue (Basal or outgroup)
Eumetazoans contain
true tissues (derived
Characteristics)
3.
Bilateria contains
organisms with
bilateral symmetry,
triploblastic
development, most are
coelomates and
contain three major
clades
1.
Lophotrochozoa
2.
Ecdysozoa
3.
Deuterostomia
(Deuterostome development and
includes chordates and
vertebrates)
Sponges
p. 670
-Thought to have been plants
-Suspension Feeders
-Water is drawn through pores and
a current provided by the flagella
-Ameobocytes take food particles
to the rest of the cells
Cnidarians (Jellyfish, Coral)
-Simple diploblast radial body plan
-Polyp adheres to something
-Medusa free moving form
-Carnivores
-No brain but responds to stimuli from
all directions
Lophotrochozoans
-Clade includes 18 phyla
-Most diverse animal
clade (very different body
plans)
-Clade is molecularly
monophyletic
Phylums include:
-Tapeworms
-Mulluscs (snails, slugs,
mussels, clams, oysters, squids
and octopuses)
-Annelids (earth worms and
leeches)
Ecdysozoa a group defined
by shedding of a tough
external coat or molting.
Complete vs Incomplete metamorphosis
-The Arthropods: most
species rich animal group
Common Characteristics
of Arthropods
1.
2.
3.
4.
Exoskeleton and Molts
Well developed senses
Open circulatory system
Four major lineages
-Spiders, ticks, mites
-Millipedes and
Centipedes
-Insects
-Crabs, lobsters, and
shrimp
Deuterostomia includes both Echinoderms and Chordates
-Based mostly on Molecular data
Derived Characteristics of Chordates
1.
2.
3.
4.
Notochord - Present in all embryos
and turns into backbone/vertebrae
Presence of a hollow dorsal nerve
chord that turns into the nervous
system
Presence of Pharyngeal slits
Presence of post anal tail
p. 734 for other derived characteristics