General characteristics•Eukaryotic

•Multicellular

• Heterotrophic

•No cell wall

•usually mobile in at least one stage of their life

•produce sexually and produce an embryo

Level of Organization

Cells Tissue Organs Organ systems Animal

General Characteristics2. Types of tissues

Tissue Gives rise to… Location

ectoderm

mesoderm

endoderm

epidermis and nervous system

circulatory, respiratory and

skeletal systems

Digestive tract

outer layer

middle layer

inner-most layer

except Phylum Cnidaria- no mesoderm

CharacteristicsSymmetry and body plan• Asymmetrical body plan: irregular

body shape • Radial symmetry:

- can be divided into equal halves by a plane passing through the central axis in any direction

• Bilateral symmetry:- body can be divided into equal halves only along a single plane- organisms with bilateral symmetry exhibit cephalization

Our body symmetry?

?Radial symm.

Cephalization

• concentration of sensory organs and nerve cells at the anterior end

• acts as a control centre• allows organism to respond to

stimuli quickly• evolutionary favoured

• Coelom: fluid-filled body cavity with organs suspended inside

• Developed from mesoderm• Presence of compartments also

means nutrients and O2 may not be diffused to every cells

• Coelomates: animals with a coelom.

• Acoelomates: animals without a coelom (e.g. corals, jelly fish and flatworms)

General Characteristics

Presence of a Body Cavity

Advantages of a Coelom

• acts as a cushion for internal organs

• provides more room for internal organs to expand

• allows animal to become larger

• allows digestive tract to develop specialized regions and formation of blood vessels

Segmentation• The division of the body into repetitive sections

e.g. worms and scorpions• A single segment can be damaged, but the other

segments can continue to function properly• Mobility is more effective because segments

move independently

Movement• Complex and fast movement• Some are sessile (stationary) as adults e.g. sponges

and sea anemones. They live attached to one place such as the bottom of the ocean or a rock.

• Sessile animals have a body form that can move during juvenile stages of development

General Characteristics

Recall • Zygote: cell formed after an egg is fertilized by a sperm• Gametes: sex cells like eggs and sperms

• Diploid: containing two copies of each chromosome (2n)

• E.g. A human zygote contains 46 chromosomes

• Haploid: containing half the usual # of chromosomes (n)

• E.g. Human eggs and sperms are gametes each contains ? chromosomes

Reproduction

• Sexually reproduction using gametes (haploid eggs and sperm meet to form a diploid zygote)

• Internal (inside female body) or external (in aquatic environment) fertilization

• Some animals switch between asexual and sexual modes, reserving sexual reproduction for when the conditions are tough

Live birth- aphid, whaleWith shelled egg- bird, platypus

General Characteristics

Duck+ beaver + otter = platypus

Master of Cloning: https://www.youtube.com/watch?v=J7eRGHVx3p0

PoriferaCnidaria

Platyhelminthes

sponges jellyfish flatwormsroundworms

Nematoda

Mollusca Arthropoda Chordata

Annelida Echinoderm

mollusks

multicellularity

Ancestral Protist

tissues

bilateral symmetry

body cavity

segmentation

Animal Evolution

coelom

starfish vertebrates

endoskeleton

segmentedworms

insectsspiders

backbone

Part II- Diversity in Animal Kingdom

Animal Diversity

Porifera (sponges)

Cnidaria

Porifera

Sessile but living

Cnidaria

Animal Diversity

Platyhelminthes (flat worm)Nematoda (round worms)

Annelida (segmented)

Platyhelminthes

ectoderm

mesodermendoderm

Planaria regenerationhttp://www.youtube.com/watch?v=vXN_5SPBPtM

Symmetry and cephalization observed in Planaria http://www.youtube.com/watch?v=w0QzSYQGsnA

NematodaC. elegans

• Roundworm: http://www.youtube.com/watch?v=DxL2qHBetvI

• Guinea worm: http://www.youtube.com/watch?v=nu3z7mRyLRc

- Loa loa is a filarial nematode (roundworm) species

- Lives in human eyes- “eyeworm”

- Hosts can feel the worm moving in the eye and can see it floating in there if it’s big enough.

- easily killed using antibiotics or is extracted through minor surgery, though it can live inside a human for up to 17 years.

Nematoda

http://www.liveleak.com/view?i=67a_1341408640&comments=1&use_old_player=0

Annelida- segmented wormfan worm leech

Animal Diversity

mollusca

echinodermata

Mollusks

http://www.ted.com/talks/david_gallo_shows_underwater_astonishments.html

Animal Diversity

crustaceans

arachnida

insecta

Diploda / chilopoda

Insecta

• Most successful invertebrate

• Parasites hijack host behaviourthe case of parasitic wasp and catepillar

http://www.youtube.com/watch?v=vMG-LWyNcAs

Echinoderms

Animal DiversityTunicates + lancelets

jawless fishcartilage fish

bony fishamphibiansreptilia

avesmammalia

Tunicates and Lancelets

Sea Lamprey- jawless fish

Parasitic eel-like creatures with suction-cup, bloodsucking mouths.Also an invasive species to the Great Lake ecosystem

Rays always look so cheerful!

Bony fish

Amphibians

Gastric brooding frogs- now extinct

Disappearing of Froghttp://www.youtube.com/watch?v=ZWHibAQ0Ssohttp://animal.discovery.com/tv-shows/other/videos/the-vanishing-frog-with-jeff-corwin.htm 1. What proportion of amphibians are in trouble?- 30%2. How long have amphibians been around?- 300 million years3. What is the disease mentioned in the video that kills off amphibians?

What is the cause of such disease?Chytrid disease caused by chytrid- an aquatic fungus that attacks frog’s

skin.4. What strategies have been done to increase frog number?- Treatment of frogs with antifungal drugs; captive breeding5. Why should we be worried about frog’s disappearing?- their dual habitats (i.e. land and water) make them good indicators of

healthy ecosystem; humans benefit from frog’s chemical; they are the link b/t terrestrial and aquatic food web

Birds- known for their feathers and …. Attitudes :

ArchaeopteryxFossil record indicates birds and reptiles are closely related

Mamalian

14 panda babies artificially bred in China

http://www.bbc.co.uk/news/world-asia-china-24223721

The Worms

Platyhelminthes

NematoNematodada

AnnelidAnnelidaa

Common

NameFlatworFlatwor

mmroundwor

mSegmenteSegmente

d wormd worm

The Worms

Platyhelminthe

s

NematoNematodada

AnnelidAnnelidaa

Type of

symmetry

bilateralbilateral bilateral bilateralbilateral

The Worms

Platyhelminthe

s

NematodNematodaa

AnnelidAnnelidaa

Type of

body cavity

nonenone

pseudocoelom(body cavity partially lined with mesoderm)

Coelom Coelom (fluid filled (fluid filled

space space completelcompletel

y lined y lined with with

mesodermmesoderm

Body Cavity

ectoderm

ectoderm

mesodermendoderm

ectodermmesoderm

endoderm

mesodermendoderm

acoelomate

pseudocoelomate

coelomate

coelom cavity

pseudocoelom

The Worms

Platyhelmint

hes

NematodNematodaa

AnnelidAnnelidaa

# and Name of Cell Layers

3 – 3 – ectoderectoder

m, m, mesodermesoderm and m and

endoderendodermm

3 – ectoderm, mesoderm and endoderm

3 – 3 – ectoderm, ectoderm, mesoderm mesoderm

and and endodermendoderm

The Worms

Platyhelminthes

NematoNematodada

AnneliAnnelidada

Cephalizatio

n? yesyes yes yesyes

The Worms

Platyhelminthes

NematodNematodaa

AnnelidAnnelidaa

Digestive

System

One One digestive digestive opening opening

(food and (food and wastes wastes through through

the same the same openingopening

Separate anus and mouth

Separate Separate anus and anus and

mouthmouth

The Worms

Platyhelminthes

NematodNematodaa

AnnelidAnnelidaa

Circ and resp. systems

Simple Simple diffusion diffusion through through

gas gas exchangeexchange

Yes – due Yes – due to large to large

sizesize

The Worms

Platyhelminthes

NematodNematodaa

AnnelidAnnelidaa

Misc. Featu

res

Exhibit 2 Exhibit 2 forms of forms of lifestyles: lifestyles: free-living free-living and and parasitic parasitic e.g. e.g. tapewormstapeworms

Thin body wall and round shape minimize minimize outer surface area

The Worms

AnnelidaAnnelida

Misc. Featu

res

Segments are identical - can increase in size without losing the capacity to transport materials and relay messages– segmentation improves movement / flexibility

Our evolutionary cousin

http://youtu.be/G32YehcdUAw

Extra material

Classification1. Invertebrates• Animals without backbones• Occupy almost all terrestrial and

aquatic ecosystems• Have existed for hundreds of

millions of years

2. Vertebrates• Phylum Chordata• Have a skull and a backbone that

protects the nervous system (brain and spinal cord)

Invertebrates1. Sponges and Cnidarians

Sponges (Phylum Porifera)

• Found in marine and freshwater environments

• Have asymmetrical body plan and no tissues

• Body consists of 2 layers of independent cells that can be separated into clumps of cells able to reassemble themselves into a whole sponge again

• Sessile adults feed by trapping food particles in water passing through their bodies

Invertebrates1. Sponges and CnidariansCnidarians (Phylum Cnidaria) e.g. corals, sea anemones, hydras• Have two layers of cells and tissues including muscle tissues able to

swim and capture food using stinging tentacles around their mouth.• Have radial body symmetry and two body forms

• Polyp: a cylindrical form that attaches to a surface, extending tentacles upward and downward

• Medusa: a flattened, mouth-down form that is not attached. They move passively with currents or actively by body contractions e.g. jellyfish

Invertebrates2. Worms

• Flatworms are acoelomates with three layers of cells

• Have simple nervous system with a brain-like concentration of cells, including an eyespot, at the head end.

• Segmented worms are coelomates

Invertebrates3. Molluscs• 3 classes: bivalves (clams), gastropods (snails) and cephalopods (octopus)• Second most diverse animal phylum• Bilateral symmetry with 3 layers of cells, a coelom and two body openings• Have a soft body that is protected by a hard shell and a mantle that

surrounds the internal organs and secretes CaCO3 for the shell

• Contain various organs, eyes, sense organs and a muscular foot for movement

Invertebrates

4. Echinoderms

• Sea stars, sea urchins, sea cucumber…

• Radial symmetry, spiny endo-skeletons (an internal skeleton that protects organs and provides support for muscle attachment.

• Have tube feet: small muscular, fluid filled tubes that are similar to suction cups

Invertebrates5. Anthropods

• Arthropod means jointed foot legs are made up of movable sections connected to joints

• Segmented bodies and a hard exoskeleton (protein + chitin) that protects the internal organs.

• Chelicerates: Spiders, scorpions, mites

• Mayriapods: centipedes and millipedes

• Insects: beetles, bees, butterflies, ants…

• Crustaceans: crabs, lobsters, shrimps…

Vertebrates

Tetrapods Embryo in a fluid-filled sac

Vertebrates1. Fish

• Lampreys are the oldest living vertebrates

• Have gills to obtain dissolved oxygen from water (rely on a suction mouth for holding on to food)

• Advanced animals have jaws, fins and bony skeleton

• Swim bladders: air sacs that allow a fish to sink or rise in water

Vertebrates2. Amphibians

• E.g. frogs, toads and salamanders

• Have moist skin to assist in gas exchange in addition to lungs

• External fertilization

Vertebrates3. Reptiles

• 3 orders remain: Squamata (lizards and snakes), Testudines (turtles), and Crocodilia (crocodiles)

• Use only lungs for gas exchange

• Ectothermic: have a 3 chambered heart relies on environmental heat for determining internal body temperature

• Internal fertilization (amniotic egg) outside incubation of shelled egg.

Vertebrates4. Birds

• Endothermic: have a 4-chambered heart that use internal metabolic heat to maintain a high, constant body temperature

• Most can fly

• Bones are lightweight and hollow, and bodies are compact keep body weight low

Vertebrates5. Mammals

• Distinct features: mammary glands (milk production) and a highly developed brains

• Hair: defence (porcupine), sensory detection (eyelashes)

• They are endothermic

5a. Monotremes

• Egg-laying mammals

• Only living example: duck-billed platyus and echidna in Australia and New Guinea

Vertebrates

5b. Marsupials

• Pouched mammals

• Have a short gestation period

• Mostly found in Australia

• E.g. koala bears and kangaroos

5c. Placental Mammals

• Have placenta

• Have great diversity in species and structure

• E.g. bats, bears, whales, primates and humans

Our evolutionary cousin

http://youtu.be/G32YehcdUAw