BIOL 1123 Animal Diversity

Domain of organisms that is the closest relative to animals

Protists

Cambrian explosion (500 MYA)

Rapid diversification of most major animal groups

How animals get their food

Heterotrophic (carnivores, herbivores, omnivores, etc.)

Animal cells have this type of life cycle

Diplontic (diploid cells)

Animals developed neurons with gap junctions for this purpose

Helps with coordinating movement

Organisms that is the closest relative to animals

Choanoflagellates

Number of phyla in the animal evolutionary tree

39 phyla

5 ways in which animals are classified

Symmetry, tissues, body cavity, embryological development, and segmentation

3 types of symmetry seen in animal anatomy

Asymmetry, radial, and bilateral

Radial symmetry

Sessile or drifting; animal senses the environment from all directions

Bilateral symmetry

Directional movement; allows for cephalization in animals (i.e., formation of the head)

3 types of germinal layers

Ectoderm, endoderm, and mesoderm

Ectoderm germinal layer

Includes epidermis, skin glands, nervous system, and sense organs

Endoderm germinal layer

Includes the digestive and respiratory systems

Mesoderm germinal layer

Includes muscles, bones, circulatory system, blood, and the body cavity

Diploblastic animals

Have 2 germinal layers (ectoderm and endoderm, not the mesoderm)

Triploblastic animals

Have 3 germinal layers (ectoderm, endoderm, and mesoderm)

Coelom

Fluid-filled cavity surrounded by mesoderm; located between the body wall and digestive tract

Functions of the coelom

Cushions organs; allows for independent movement of organs; supports larger body sizes; enables circulatory system efficiency; compartmentalization of body systems

3 types of animal groups based on the presence or absence of coelom

Acoelomate, pseudocoelomate, and coelomate

Blastospore

First opening of the embryo, which becomes either the anus or the mouth

Protostome

Animal whose mouth is formed from its blastospore

Deuterostomes

Animal whose anus is formed form its blastospore

What does it mean for an animal to have an incomplete digestive system?

They have a single opening that serves as both the mouth and anus

What does it mean for an animal to have a complete digestive system?

They have two openings: one for the mouth, and the other for the anus

Invertebrate animal that has no symmetry, no true tissues, and is immobile (anchored)

Sponges

Structure of a sponge

Has a central cavity (i.e., spongocoel) surrounded by a body with pores for nutrients to go in and out

Sponges are filter feeders and have both male and female reproductive parts, so they have these 2 characteristics

They are choanocytes and hermaphrodites

Invertebrate animals with radial symmetry, true tissues, and have stinging cells on their tentacles

Cnidarians

2 types of cnidarian forms

Polyps are immobile and medusa are mobile

The cnidarian has its central digestive and circulatory systems in this cavity

Gastrovascular cavity

Examples of cnidarians

Anemones, hydras, corals, and jellyfish

Cnidarians use the medusa form for this type of reproduction

Sexual reproduction

Cnidarians use the polyp form for this type of reproduction

Asexual reproduction

Invertebrate animals with eyespots and bilateral symmetry; found in marine, freshwater, and damp habitats; attached to rocks

Flatworms

Name of the phylum in which flatworms belong

Platyhelminthes

Flatworms have an incomplete digestive system, meaning they have this cavity

Gastrovascular cavity

Example of a flatworm (Platyhelminthes)

Tapeworm

Invertebrate and segmented animals with a complete digestive system and a closed circulatory system

Annelids

Example of an Annelid

Earthworms

Invertebrate animals with cylindrical bodies; found in all ecosystems; recycle nutrients and have a complete digestive system

Roundworms

Name of the phylum in which roundworms belong

Nematoda

Example of a roundworm (Nematoda)

C. elegans

Soft-bodied, invertebrate marine animals that are protected by an internal or external shell made of calcium carbonate and have a complete digestive system

Mollusks

3 body parts of a mollusk

Muscular foot, visceral mass, and mantle

Examples of mollusks

Snail, squid, giant clam, and chambered nautilus

Name of the saw-like organ used to grind food in mollusks

Radula

Name of the respiratory structure in mollusks

Gills

Mollusks, annelids, arthropods, echinoderms, and chordates have a fluid-filled cavity surrounded by mesoderm, so they are classified as this

Eucoelomates/coelomates

Largest phylum of invertebrate animals with a segmented body (head, thorax, and abdomen), jointed appendages, and an exoskeleton

Arthropods

4 sub-phyla that make up Arthropods

Chelicerates, Myriapods, Crustaceans, and Insects

Arthropod sup-phyla that are mostly formed by arachnids; also includes horseshoe crabs, scorpions, ticks, and mites; have 8 legs and fangs

Chelicerates

Arthropod sub-phyla that include millipedes and centipedes; are terrestrial animals

Myriapods

Arthropod sub-phyla that live in water (except for pill bugs); includes shrimps, crabs, and lobsters

Crustaceans

Largest arthropod sub-phyla; animals have 3 pairs of legs, 1 pair of antennae, and 2 pairs of wings

Insects

Invertebrate ocean animals with bumpy surfaces and slow movement that are the closest phylum to Chordates; have an endoskeleton made of calcareous ossicles

Echinoderms

2 different types of symmetry that Echinoderms have during their adult and larvae forms

Radial symmetry in adults and bilateral symmetry in larvae

Echinoderms have this type of vascular system and had their blastospore form their anus first, meaning they are classified as this

Have a water vascular system and are deuterostomes

Mostly vertebrate (but can also include invertebrate) animals with a post-anal tail, dorsal hollow nerve cord, notochord, and pharyngeal slits or clefts

Chordates

Examples of invertebrate chordates

Lancelets and Tunicates; they are filter feeders

First 4 types of vertebrate chordates

Jawless fishes, cartilaginous fishes, bony fishes, and lobe-finned fishes

Term for animals that originated 500 MYA with vertebrate bones, skulls, or cartilaginous backbones, and more complex nervous systems

Vertebrates

Examples of jawless fishes

Hagfishes and lampreys

Examples of cartilaginous fishes

Sharks and stingrays

One of the first four types of vertebrate chordates that have scales, a swim bladder, and an operculum to move water throughout their gills

Bony fishes

Examples of lobe-finned fishes

Coelacanths and lung fishes

One of the first four types of vertebrate chordates that is the common ancestor to amphibians due to their muscular fins supported by small bones

Lobe-finned fishes

Vertebrate chordate animals that are the first tetrapod (e.g., TikTaalik) and live in damp habitats

Amphibians

3 groups of vertebrate chordate amphibians

Salamanders, frogs/toads, and caecilians

Vertebrate chordate animals that appeared 310 MYA; their full life cycle happens on land, and have internal fertilization; have scales; most are ectothermic, but some are endothermic

Reptiles

Reptiles are vertebrate chordate animals whose eggs have a shell to prevent dehydration during embryonic development, so they are classified as this

Amniotes

4 groups of vertebrate chordate reptiles

Turtles, crocodilians, dinosaurs/birds, and lizards/snakes

Vertebrate chordate animals that are amniotic, have mammary glands, hair (insulation, water retention, and protection), are endothermic, and have bigger brains

Mammals

3 lineages of vertebrate chordate mammals and their definitions

Monotremes (egg-laying), marsupials (have pouches), and eutherians (have placentas)

One example from each of the 3 lineages of vertebrate chordate mammals

Echidnas (monotremes), koalas (marsupials), and dogs (eutherians)