general characteristics eukaryotic multicellular heterotrophic no cell wall usually mobile in at...
TRANSCRIPT
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