The animal kingdom

What is an Animal? Eukaryotic Multicellular Do not have a cell wall Heterotrophs Mobile at one point in their life Reproduce sexually

Do you have a backbone? YES! Vertebrates have a backbone and skeleton Invertebrates do not have a backbone 95% of all animals!

Characteristics used to classify Animals Levels of organization: cells, tissues, organs, organ tissues Number of body layers during development Ectoderm(skin), mesoderm(muscle), endoderm (lungs) Symmetry: Symmetrical or Asymmetrical Radial Symmetry: Organism can be divided along any plane and be symmetrical Bilateral Symmetry: Can only be divided along one axis

Body Cavities Segmentation: Body is broken into repetitive sections Movement Reproduction: Reproduce sexually via gamete production

Invertebrates

Sponges and Cnidarians Found in salt and fresh water Asymmetrical body Two layers of tissue They are sessile WHAT??????

Cnidarians: Like jellyfish and coral Two body forms: Polyp: Sessile, tube shaped Medusa: Free Swimming, umbrella shaped

Cnidarians

2) Worms Simple nervous system with a brain-like concentration of cells They have a segmented body = ANNELIDS

3) Molluscs Like clams, mussels and oyster's Bilateral symmetry Three layers of cells Soft body, protected by a hard shell in some

4) Echinoderms Like sea urchins, sea cucumbers Marine animals Radial symmetry Spiny endoskeletons = internal skeleton that protects the organs Have tube feet, which acts as suction cups

5)Arthropods Spiders, scorpions and insects OH MY! Largest phylum! They have a hard exoskeleton, which acts to protect and prevent drying out Have legs with many segmented parts.

Vertebrates – phylum chordata Organized into 5 classes: fish, amphibians, reptiles, birds and animals Aside form fish, the other four classes developed from tetrapods – a vertebrate with 2 pairs of limbs Common characteristics: They have a notochord = rod shape that extends the length of the body They have a dorsal nerve = tube shape cord

Class - fish All have gills to obtain dissolved oxygen from water Habitat: fresh water or salt water Size: <1cm (dwarf carp)  12m (whale shark) Evolved traits: Paired fins & jaws  sharks and rays Skeleton  “bony fish” Oldest fish = lamprey – no fins, no jaw, no skeleton!

Class - Amphibians First “terrestrial” tetrapods Their life cycle is only partially on land Able to do this because of the evolution of lungs and using their skin as an organ for gas exchange They mostly reproduce using external fertilization

Class - Reptiles Divided into 3 orders of reptiles: 1) lizards and snakes 2) turtles 3) crocodilians Evolved to not be dependent on living in aquatic ecosystems Development of body scales = waterproof barrier to prevent dehydration Dependent on lungs (no moist skin!) Shelled eggs = prevent dehydration Internal fertilization, since no longer in aquatic environments!

Class - Birds Evolved after reptiles Have feathers Most birds can fly Weight saving adaptations Bones are lightweight and hollow Toothless skull Compact bodies Internal fertilization and shelled eggs, like reptiles

Reptiles vs Birds Although related, based on common characteristics, there are differences that have evolved: Difference #1 Reptiles = ectothermic – dependent on environment for body temp Birds = endothermic – use own metabolism to determine body temp

Difference #2 Reptiles – circulatory system has a 3 chamber heart Birds – have a four chamber heart

Class - mammals Endothermic, 4 heart chambers, well developed brains… Have mammary glands (females) – production of milk for young Have hair for multiple purposes: Insulation Communication / defense Camouflage Some species have “reduced” hair – like humans, elephants and mole rats

Mammals – into 3 groups Momotremes Egg laying mammals! Only examples: duck billed platypus 2) Marsupials Pouched mammals Ex. Kangaroos and koala bears

3) Placental mammals Have a placenta – organ that develops during pregnancy for nutrient and oxygen exchange between the mother and developing offspring

Echinoderm

Amphibian

Arthropods

Molluscs

Mammal-Marsupials

HW: Pg 124 #11-14