Animal Diversity I

Animals are ____trophic

heterotrophic

cell structure of animals

eukaryotic, no cell wall

animals shared derived character

extracellular matrix

extracellular matrix functions

collagen;

connection & support

All animals are ____cellular.

multicellular

All animals have specialized ____.

cells

Most animals have specialized ____.

tissues

Higher forms of animals have specialized ____.

organs

draw embryonic development in animals

sequence embryonic development in animals

1. zygote

2. cleavage

3. blastulation

4. gastrulation

cleavage

mitotic divisions without cell growth

blastulation

more cleavage and ball becomes hollow, forming a blastula

gastrulation

folds inward and expands into blastocoel, forming a gastrula

homeobox genes

code for proteins that regulate development → morphology

body plan

set of morphological and developmental characters that represent key steps in evolution

draw the metazoa (kingdom animalia) phylogeny

symmetry

arrangement of body structures in relation to an axis of the body

asymmetry

no line produces mirror images

two types of symmetry

1. radial

2. bilateral

radial symmetry

multiple planes produce mirror images;

no right and left sides;

sessile and planktonic animals

bilateral symmetry

only one plane through midline produces mirror images;

right and left halves;

cephalization

cephalization

concentration of nerve tissues at the anterior end of the individual;

CNS;

coordinate complex movements

What is the basal metazoan that does not have specialized tissues?

porifera (sponges)

Which clade has specialized tissues?

eumetazoa

draw embryonic tissue development

What are the 3 germ layers of embryonic tissue development?

1. ectoderm

2. mesoderm

3. endoderm

ectoderm

outer covering and nervous system;

all eumetazoans

endoderm

lines archenteron;

lining of digestive tube and organs;

all eumetazoans

mesoderm

layer between the ectoderm and endoderm;

most other body structures;

not all eumetazoans

diploblastic

develop only ectoderm and endoderm layers

triploblastic

develop all 3 layers: ectoderm, mesoderm, and endoderm

coelom

fluid-filled space between the body wall and digestive tube

The coelom is only in…

triploblasts

3 types of body cavities

1. acoelomate

2. pseudocoelomate

3. eucoelomate

acoelomate

ancestor had coelom, but it was lost

pseudocoelomate

coelom lined by (in between) endoderm and mesoderm

eucoelomate

true coelom;

completely lined with mesoderm

3 processes of animal development

1. cleavage

2. coelom formation

3. fate of blastopore

Differences in animal development separate Nephrozoa into…

protostomes and deuterostomes

cleavage stage for protostomes

spiral and determinate

spiral cleavage

planes of division are diagonal to the vertical axis

determinate cleavage

developmental fate is rigid;

if a cell is removed → adult lacks parts

protostomes 3 stages

1. cleavage

2. solid masses of mesoderm split to form coelom

3. mouth develops from blastopore

draw protostome development

cleavage stage for deuterostomes

radial and indeterminate

radial cleavage

planes parallel or perpendicular to the vertical axis

indeterminate cleavage

each cell in early divisions is able to develop into a complete embryo

deuterostome 3 stages

1. cleavage

2. mesoderm from archenteron folds to form coelom

3. anus develops from blastopore

draw deuterostome development

choanoflagellates

• protists

• sister taxon to animals

CA of all animals lived…

770 mya

Sponges originated around…

700 mya

basal taxon of clade metazoa

phylum porifera

basal taxon of clade eumetazoa

phylum cnidaria

basal taxon of clade bilateria

phylum acoela

Cambrian explosion

535 - 525 mya;

rapid diversification

When were most of the current phyla established?

~ 500 mya

metazoa clade

• porifera

• cnidaria

• acoela

• echinodermata

• chordata

• platyhelminthes

• rotifera

• mollusca

• annelida

• nematoda

• arthropoda

metazoa basal taxon

porifera

metazoa SDC

ECM

porifera SDC

• asymmetry

• no specialized tissues