Introduction to Animals Essential Questions: What makes an animal an animal? How are animals classified?

Kingdom Animalia  Eukaryotic  Heterotrophic  Multicellular Tissues and organs formed by specialized cells  No cell walls  Likely evolved from animal-like protists

Essential Functions All animals carry out the following: 1. Obtain food from the environment 2. Exchange O 2 & CO 2 through skin, gills, lungs, etc 3. Move materials around body 4. Get rid of wastes 5. Process information with nerves 6. All animals are motile at some point 7. Most reproduce sexually, some asexually

Reproduction & Development  Animals mainly reproduce sexually Fertilization – sperm meets egg, either within or outside the body External fertilization (in water) External fertilization (in water) Internal fertilization (on land) Internal fertilization (on land) What are the positives and negatives of each type of fertilization?

Reproduction & Development  Steps of Development:  Fertilization results in a unicellular zygote  The unicellular zygote divides by mitosis = cleavage  A hollow ball of cells (blastula) forms  Gastrulation (folding inward) forms 2 cells layers: ectoderm and endoderm  Mesoderm forms

Coelomate vs Acoelomates  Coelom – fluid filled cavity that supports internal organs.  Acoelomates – no internal cavity. Example: Flatworms  Pseudocoelomates – body cavity develops between endoderm and mesoderm. Example: Roundworms  Coelomates – internal organs suspended in a body cavity surrounded by mesoderm. Example: Earthworms Why the Coelom? The coelom is significant because as animals evolved, so did the presence of a complex body cavity to support more complex organs!

Symmetry  Animals can be described in terms of their symmetry:  Asymmetry – irregular in shape Example: Sponge  Radial Symmetry – can be divided through along any plane into halves from the mouth. Example: Anemone  Bilateral Symmetry – can be divided lengthwise into 2 mirror images. Example: Humans  Cephalization: concentration of sense organs at the front (top) of the body

Body Positioning Bisymmetrical animals have 4 parts:  Anterior: the head end, where sensory organs are located  Posterior: the tail end (anus)  Dorsal: Back surface where the spine is located  Ventral: The belly side

Framework for support: Skeletons  Exoskeletons – hard, waxy covering on the exterior of the body. Prevent water loss, protect soft tissues  Endoskeletons – internal skeleton for support made of Calcium Carbonate, cartilage or bone Protects internal organs and an internal brace for muscles to pull against To survive on land, why is it important to have a strong skeleton?

Framework for support: Skeletons  Invertebrates – an animal without a backbone; usually has exoskeleton Echinoderms have endoskeletons  Vertebrates – an animal with a backbone; bilaterally symmetry; exoskeleton

Invertebrates  Make up 95% of all animals  No backbone, or vertebral column. Most have exoskeletons.  Open circulatory systems (with a one chambered “heart”) Cannot process Oxygen very well, restricts their size and survival on land. Cannot process Oxygen very well, restricts their size and survival on land.

Invertebrate Phyla  Phylum Porifera - Sponges  Phylum Cnidaria – Corals, Hydra & Jellyfish  Phylum Platyhelminthes - Flatworms  Phylum Nematoda – Roundworms  Phylum Mollusca – Snails, squid & Clams  Phylum Annelida - Segmented Worms  Phylum Arthropoda – Insects, spiders, lobsters  Phylum Enchinodermata – Starfish  Invertebrate members of Phylum Chordata– Sea squirts, Lancelets

Phylum Annelida  The segmented worms. Example: earthworms, leeches Segmentation allows movement of individual parts Segmentation allows movement of individual parts  Possess a true coelom  Specialized organs and systems

Phylum Chordata Subphylum Vertebrata Class Agnatha (jawless fishes)Agnatha Class Chondrichthyes (cartilaginous fishes)Chondrichthyes Class Osteichthyes (bony fishes)Osteichthyes Class Amphibia (amphibians)Amphibia Class Reptilia (reptiles)Reptilia Class Aves (birds)Aves Class Mammalia (mammals)Mammalia

Vertebrates  5% of all animals  Have a vertebral column.  The backbone gives support to the body and protection to the spinal cord  Have endoskeletons.  Closed circulatory system with a multichambered heart  Classification: Kingdom – Animalia, Phylum – Chordata, Subphylum - Vertebrata

Types of Mammals  Subclasses – based on type of reproduction Placental (95%) – young fully develops in uterus before birth Placental (95%) – young fully develops in uterus before birth Marsupials – short period of development inside the mother followed by a second period of development inside pouch Marsupials – short period of development inside the mother followed by a second period of development inside pouch Monotremes - lay eggs. # species: platypus and 2 echidnas Monotremes - lay eggs. # species: platypus and 2 echidnas

Vertebrates: Am I hot or not?  The major difference between vertebrates is whether or not they can regulate their own body temperature.  Ectotherms – regulated by environment Example: fish, frogs, snakes Example: fish, frogs, snakes  Endotherms – regulated by their own body Example: mammals Example: mammals

Animals that are ectothermic (like snakes) don’t require food as much as endotherms.  What does this indicate about the relationship between food requirements and the generation of body heat?  How does this fact restrict where certain types of animals can live?  If the environment were to suddenly get cold (like an ice age), which of the animals could survive?