Chapter 27- Introduction to Animal Diversity

Features of the Aninmal Kingdom

Multicellular eukaryotes

heterotrophy

active movement

reproduction

embryonic development

body plan

Features of Kingdom Animalia- Cells joined together by

• protein-rich extracellular matrix (ECM)

• with collagen (protein unique to animals)

Features of Kingdom Animalia- Most animals have integrated organ systems

- exchange chemicals with external environment

- maintain internal homeostasis thru feedback mechanisms

- if key system fails, the animal dies

Digestive system

body system the breaks down food and absorbs nutrients

circulatory system

Transports oxygen, waste, nutrients, hormones, heat, etc... around the body

respiratory system

system responsible for taking in oxygen and releasing carbon dioxide using the lungs

excretory system

the system that removes waste from your body and controls water balance

Features of Kingdom Animalia- Most animals have nerve cells (neurons) & muscle cells

• unique to animals

• sensory receptors detect stimulus

• motor response produces movement

motor response produces movement through the

• sensory neuron

• interneuron

• motor neuron

• muscle

Animal Life Cycle- Sexual reproduction

in almost all

most: separate sexes (but sex may change)

some: hermaphroditic = M/F in 1 individual

Animal Life Cycle- Asexual reproduction in some

• fragmentation & regeneration

• budding

• rare: parthenogenesis = virgin females produce eggs that develop into offspring

do most animals have a larval stage

yes

how do larva differ from adults

form, function & often habitat

what is it called when a larva turns into an adult

metamorphosis

animals wihtout larva stage have what, and how is that different from adult

juvenile

looks similar to the adult but it smaller and less mature

Features of Kingdom Animalia- With embryonic development

• most animals have similar genes that control development, including "Hox" genes

embryonic development steps

zygote >> cleavage >> 8 cell stage >> cleavage >> blastula >> gastrulation >> gastrula

gastrulation forms the gastrula stage

• with blastopore & archenteron

• creates germ layers (origins of tissues)

Endoderm & ectoderm form first....

then mesoderm later forms between them

endoderm

The inner germ layer that develops into the lining

digestive tract; internal organs, lungs

ectoderm

outermost germ layer developed with gastrulation

give rise to outer covering and nerves

medoderm

middle layer only in triploblastic

muscle, bone, blood, etc

How many germ layers do most animals have

2 or 3

diploblastic

2 germ layers

triploblastic

3 germ layers

add mesoderm

two developmental patterns of triploblastic

protosomes and deuterostome

protostomes

coelom forms froms splits in the mesoderm

the mouth forms from the blastopore FIRST

deuterostomes

coelom forms from mesodermal outpocketing of the archenteron

the anus develops at the site of blastospore FIRST

spiral cleavage

planes of cell division are at oblique angles to the axis of embryo

protosome devlopment

radial cleavage

planes of cell division are parallel or perpendicular to the axis of embryo

deuterostome development

body plan features include

- symmetry

- body cavities

- segmentation

- presence and function of appendages

radial symmetry

Symmetry around a central axis.

usually sessile or planktonic

no left, right, front or back sides

sessile vs planktonic

attached vs. drifting

bilateral symmetry

two axes of orientation- front to back and top to bottom

usually has head

active lifestyle

animal example of bilateral symmetry

lobster

coelom

fluid-filled body cavity lined with mesoderm

what does a coelom allow and purpose

internal organs to grow and move

cushion internal organs

true coelom

forms form tissue derived form mesoderm

pseudocoelom

body cavity formed from the mesoderm and endoderm

Acoelomates

have no body cavity

Hox gene

controls the organs and tissues that develop in various parts of the embryo

what does the Hox gene encode and determine

transcription factors

determines the course of embryonic development

where do genes with the Hox clusters express

certain body segments at certain stages of development

one common ancestor of animals

Choanoflagellates are closest protist group to animals

choanoflagellate characteristics

small, no cell wall

no fossil record

collar cells and genes

closest protist group to animals

choanoflagellates

first animals were...

sponge-like

Proterozoic (pre cambrain) animals

ediacarcan biota-

earliest known animal fossil

soft bodied, sponges, jellyfish-like, worm- like

Paleozoic Era animals

"Cambrian explosion"

-animal diversification

-almost all major major phyla

-First mineralized skeletons, shells

Later Paleozoic Era

-Vertebrate fishes dominate seas

-Arthropods invade land

-Later, vertebrates invade land (amphibians)

-Finally, first reptile-like amniotes

Mesozoic Era animals

-dinosaurs, pterosaurs, aquatic reptiles

-origin of birds and mammals

-end: cretaceous extinctions

Cenozoic Era Animals

diversification of modern groups

what are animal phylogenies based on

analyzing whole genomes

morphological traits

rRNA genes

Hox genes

protein-coding nuclera genes

mitochondrial genes

inferences from the animal phylogentic tree

all share a common ancestor

sponges are all animals sister group

eumetazoa is a clade of animals w tissues

most animal phyla belong to the clade bilateria

3 major clades of bilaterian animals

1. Deuterostomia

2. Lophotrochozoa

3. Ecdysozoa