Animals Flashcards
Tight junctions
Prevent fluid from moving across a layer of cells
Desmosomes
Connected to cytoskeleton
Space between: spot rivets
Gap junctions
Ions pass between cells
Development
Single cell -> blastula -> gastrula
Blastula
Hollow ball of cells
Stage of embryonic development
Blastocoel
Cavity of blastula
Gastrulation
Cells move from outside of blastula to inside
Archenteron
Gut
Protostome
“1st the mouth”
8 cell stage: top tier of cells sits in the furrow of the bottom tier (spiral and determinate)
Mesoderm splits to form coelom
Mouth develops from blastophore
Blastophore
Opening of gastrula
Deuterostome
"2nd the mouth" 8 cell stage: cells stack on top of each other Each cell is capable of forming a larva Folds of archenteron form coelom Anus develops from blastophore
Radial symmetry
Distinct top and bottom sides
No distinct left and right sides
Bilateral symmetry
Distinct top, bottom, right, and left sides
Coelom
Body cavity
Diploblast
Only ectoderm and endoderm
Ectoderm and endoderm
Outside cell layer and inside cell layer of embryo, respectively
Triploblast
Ectoderm, endoderm, and mesoderm
Coelomate
Mesoderm tissue layers line ectoderm and coelom (suspend internal organs)
Pseudocoelomate
Mesoderm lines ectoderm, but not coelom
Fluid lines coelom
Acoelomate
Mesoderm tissue fills space between digestive tract and ectoderm
Porifera
Sponges No true tissues Hermaphrodites Sessile (stuck to site) Flagellated swimming larvae
Sponge body plan
Pores
Spongocoel (central cavity)
Choanocytes (flagellated and collared cells that engulf food)
Ameobocytes (eat food, carry nutrients, manufacture skeletal fibers)
Osculum (large opening)
Cnidaria
Jellies, corals, hydras
Radial symmetry
Central gastrovascular cavity
Diploblastic
2 forms: polyp (hydra) or medusae (jelly)
Asexual (budding) and sexual reproduction
Cnidocytes
Structures on cnidaria tentacles that release sticky chemicals that bind and/or stun prey
Nematocysts: more complex cnidocytes
Hydrozoa
Cnidarians
Hydra
Scyphozoa
Cnidarians
Jellyfishes
No polyps
Cubozoa
Cnidarians Box-shaped Lens and cornea, but no brain Simple light-sensing cells Sea wasp
Anthozoa
Cnidarians
Coral and anemone
No medusae
Contain symbiotic bacteria
Lophotrochozoa
Bilateral symmetry
Triploblastic
Most are coelomates
Lophophore
Crown of feeding tentacles
Trocophore
Ciliated larval stage
Platyhelminthes
Lophotrochozoans Flatworms Acoelomate Gas exchange and waste: diffusion Gastrovascular cavity: one opening and branching Parasitic: require 2 hosts (Flukes) Regenerative abilities Eyespots (planaria)
Turbellaria
Platyhelminthes
Typical flatworms
Monogenea
Platyhelminthes
No complex 2-host life cycles
Trematoda
Platyhelminthes
Flukes
Complex 2-host life cycles
Cestoda
Platyhelminthes
Tapeworms
Scolex: mouth
Proglottids: sacs of sex organs
Rotifers
Lophotrocozoans
Pseudocoelomate
Alimentary canal
Suspension feeders
Parthenogenesis: females lay eggs that develop into grown females (no sperm required)
Rotifer (“wheel bearer”): crown of cilia that draws in food
Ectoprocta
Lophotrocozoans Coelomates U-shaped alimentary canals Lophophores: suspension feeders Bryozoans: colonial reef builders
Brachiopods
Lophotrocozoans Coelomates U-shaped alimentary canals Lophophores: suspension feeders Lamp shells
Mollusca
Lophotrocozoans Coelomates Foot: muscular, movement Visceral mass: contains internal organs Mantle: tissue that secretes shell Radula: "tongue" with teeth for scraping Trochopores Reproduction: mostly separate sexes, some hermaphrodites
Polyplacophora
Mollusks "Many plates" Herbivores Radula: scrape algae Strong muscular foot: difficult to dislodge
Gastropoda
Mollusks "Stomach foot" No shell: slugs Simple shell: limpet Coiled shell: snails
Bivalvia
Mollusks Clams, mussels, scallops, and oysters Suspension feeders 2-part hinged shell No head or radula
Cephalopoda
Mollusks "Head foot" Squid, octopus, cuttlefish, nautilus Carnivores: tentacles and beak-like jaw Shell reduced or missing Well developed sense organs and brain Closed circulatory system
Annelida
Lophotrocozoans Worms and leeches Coelomates Segmented Closed circulatory systems No heart Alimentary canal
Oligochaeta
Annelids "Few hairs" Earthworms and leeches Worms: chaetae (chitin bristles) Leeches: no chaetae, predators or parasites, hirudin (chemical secreted to prevent blood from coagulating)
Polychaeta
Annelids "Many bristles" Parapodia: ridges/paddles used for moving Chaetae Free living or tube dwellers
Ecdysozoa
Bilateral
Protostomes
Exoskeletons
Ecdysis
Molting
Nematoda
Ecdysozoans Round worms Pseudocoelomates Alimentary canal Free-living or parasite Usually separate sexes C. elegans: model organism for genetics, hermaphrodite Trichinella spiralis: causes trichinosis, hatch in intestine and burrow into other tissues
Arthropoda
Ecdysozoans
Coelomates
Segmented
Jointed appendages
Open circulatory system w/ hemolymph
Gas exchange: gills, trachael system, or book lungs
Exoskeleton made of chitin (provide protection, support muscles, prevent desiccation)
Cheliceriformes
Arthropods Horseshoe crabs, arachnids Chelicerae: claw-like feeding appendages Pedipalps: sensory organs located near anterior end (pincers in scorpions) Cephalothorax and abdomen 6 pairs of appendages (4 pairs of legs, 1 pair chelicerae, 1 pair pedipalps) Single-lens eyes Spiders: booklungs
Myriapoda
Arthropods Millipedes and centipedes Antannae Mandibles: jaw-like mouthparts Many legs: millipedes 2/segment, centipedes 1/segment Millipedes: herbivores Centipedes: carnivores
Hexapoda
Arthropods Insects 3 body regions: head, thorax, abdomen Wings 3 pairs of legs, antennae, specialized mouthparts Compound eyes
Incomplete metamorphosis
Eggs -> nymphs -> adults
Complete metamorphosis
Eggs -> larva -> pupa -> adult
Crustacea
Arthropods
Shrimp, lobster, crab, crayfish, barnacles
Body in 2-3 parts
2 pairs of antennae, 3 or more legs, 3 or more appendages for chewing
Compound eyes
Gills
Exoskeleton hardened w/ calcium carbonate
Echinodermata
“Spiny skin”
Starfish and sea urchins
Endoskeleton of calcified plates
Water vascular system: moving, feeding, gas exchange
Larvae: bilateral symmetry
Adult: imperfect radial symmetry
Reproduction: males and females release gametes into water
Echinodermata body plan
Ring canal, 5 radial canals
Tube feet: ampulla, sucker podium
Madreporite (mother pore)
“Nervous system:” nerve ring and nerve cords
Asteroides
Echinodermates
Sea stars
Ophiuroidea
Echinodermates
Brittle stars
Echinoidea
Echinodermates
Urchins and sand dollars
Sea urchins: experimental model for developmental biology, edible gonads
Crinoidea
Echinodermates
Feather stars
Holothuroidea
Echinodermates
Sea cucumbers
Chordates
Notochord: part of mesoderm that directs building of nerve tube under ectoderm
Pharyngeal slits: invertebrates- filter feeding, fish-gills, tetrapods- ear, head, neck
Dorsal, hollow nerve cord
Post-anal tail
Cephalochordata
Lancelets or amphioxus
Larval and adult stages have chordate characteristics
Somite: forms muscles in amphioxus, forms vertebrae, ribs, back muscles, and more in vertebrates
Urochordata
Tunicates/Sea Squirts
Larval stage has chordate characteristics
Adult sessile
Craniate Characteristics
Head with sense organs and brain enclosed in skull
Neural crest cells
Higher metabolic rate
2 chambered heart
Hemoglobin in red blood cells
Kidneys
Pharyngeal slits become respiratory gills
Neural crest cells
Give rise to teeth, bones and cartilage of skull, dermis of face, certain types of neurons
Involved in development of eyes and other sense organs
Myxini
Craniates Hagfishes Cartilaginous skull No jaws or vertebrae Slime glands
Vertebrate characteristics
More extensive skull Backbone/vertebrae and internal skeleton Paired muscle masses Central nervous system Heart w/ 2 or more chambers
Petromyzontida
Vertebrates Lampreys (jawless fishes) Skeleton made of cartilage No jaws Larval stage looks like a lancelet (cephalochordate) Adults retain notochord
Gnathostomes
Vertebrates
Jaws-hinged mouth gripping
Evolution from pharyngeal slits
Addition duplications of Hox genes
Chondrichthyes
Gnathostomes
Sharks, rays and ratfishes
Cartilaginous skeleton
Cloaca: single opening for intestinal, reproductive, and urinary tracts
Osteichthyes
Gnathostomes Ray fin fishes and lobe fin fishes Bony skeleton Rod shaped bones in pectoral and pelvic fins Some have lungs
Tetrapods
4 feet and limbs
Head separated from body by neck
Pharyngeal slits turn into ears
Urodela
Amphibians
Salamanders
Anura
Amphibians
Frogs
Metamorphosis
Apoda
Caecilians (legless amphibians)
Gas exchange via lungs and skin
Amniotes
Amniotic egg Amnion: membrane that covers embryo Chorion: gas exchange Allantois: waste disposal Yolk sac: nutrients for embryo
Reptilia
Leathery shelled eggs Ectothermic Tuatara Squamates (scaled reptiles) Turtles Crocodilians Birds
Aves
Reptiles Birds Large brain to body size Loss or fusion of bones Highly pneumatic skeleton No teeth in jaw 4 chambered heart Air sacs for efficient respiration Endothermic Feathers
Mammalia
Hair Mammary glands Endothermic 4 chambered heart Diaphragm
