Animal Diversity Flashcards
Basic Animal Characteristics
- Heterotrophic lifestyle (consuming other organisms)
- Flexible cell membrane (associated with Extracellular Matric ECM)
- Glycogen as an energy storage products (comparable to starch in plants)
- Neuromuscular Tissue (associated with movement, most animals show movement at least in larval stage)
Protist Ancestors of Animalia
- Choanoflagellate protists are the closest living relative of the animals
- Phylum Porifera (sponges) is most ancient animal phylum with living representatives. similarity between feeding cell members of the choanoclagellate and choanocyte cells of the sponges
- “micro feeders”: flagellated collar cells show a phylogenic connection between protists and animals, and support belief that these specialized cells evolved when only the smallest suspended organisms were available as food ( bacteria and early protists) sponges are only animals able to capture such small food items
Choanocyte cells
cells with an attached cylinder of microfibrils within which a flagellum resides
Fundamental Traits used to define major animal groups
Number of germ layers
- no primary germ layer
- Diploblastic
- Triploblastic
No primary germ layer
Although cells come together to function as a multicellular organism, cells remain totipotent
Ex: sponges, spongebob intro
Diploblastic
Two germ layers form
1. Ectoderm: outer layer, skin and nervous system
2. Endoderm: inner layer, lining of the digestive tract
Ex: jellyfish
Triploblastic
Three germ layers
1. Ectoderm: skin & nervous system
2. Endoderm: Lining of digestive tract
3. Mesoderm: everything inbetween Endo and Ecto, gives rise to bones, muscles, organ systems, etc
Ex: all other animals
Symmetry In animals
Asymmetry
cannot be devided into equal but oppsite halves
ex: sponges
Symmetry In animals
Radial Symmetry
- many planes can divide an organism into multiple equal but opposite parts.
- Equal response in all directions, no leading edge
Ex: starfish
Symmetry In animals
Bilateral Symmetry
Only one plane will divide the animal into equal halfs
Ex: Humans
Body Cavity
Types of animals with mesoderm
- Acoelomate
- Pseudocoelomate
- Eucoelomate
Types of animals with mesoderm
Acoelomate
no body cavity exists
ex: flatworms
Types of animals with mesoderm
Pseudocoelomate
- Has a body cavity without mesodermal lining of organs
- allows for easier diffusion of substances within organism
- rubbing between organs and body wall occurs and is potentially harmful
Ex: nemotodes
Types of animals with mesoderm
Eucoelomate
- animal has a body cavity and internal organs covered with a membrane derived from mesoderm
- protects against organs rubbing
- protects against foreign antigens entering a wound
- found in most higher organisms
Embryology
Blastosphere
animal embryo at early stage when its just a hollow ball of cells
Embryology
Blastopore
hole formed in blastosphere that becomes either mouth or anus of animal
Embryology
Protostomes
animals where blastopore becomes mouth
Embryology
Deuterostomes
animals where blastopore becomes anus
Phylum Porifera
- asymmetrical animals without germ layer
- sponges
- did not give rise to any other existing phyla
- benthic (bottom dwelling), sessile, filter-feeders with variable body size
- water canals throughout body
- few competitors in early seas, but evolved chemical defense and sharp spicule physical defense (like fiberglass insulation)
commercial sponge strade has been replaced by invention of synthetic sponges
Phylum Cnidaria
- diploblastic, radial symmetry
- animnals containing cnidocyte cells (Coral, Jellyfish, anemones)
- evolved when macroscopic protists were abundant, well after sponges evolved
- were sessile or slow moving
- used nematocysts in cnidocyte cells to capture prey and for defense
- Sessile forms supplement energy with a mutualistic algae (ex: coral)
- most have a multipurpose, blind, gastrovascular cavity, extending to most of the body tissues for nutrient delivery
Phylum Cnidaria
Nematocyst
- Paralyzing harpoons launched by coiled tube within cnidocyte cells
- exist only within cnidarians
Lophotochozoan Protosomes
- Triploblastic, bilateral symmetry
- protostome
- show growth by incremental additions to the body (without having to shed to grow)
Cephalization
concentration of sense organs and nervous system at the front of an organism,
Lophotochozoan Protosomes
Phylum Platyhelminthes
Flatworms
- Triploblastic, bilateral symmetry
- Flatworms, parasitic flukes, and tapeworms
- cephalization
- tube-within-a-tube design
- flat body maximizes surface area for diffusion of gases (no respiratory system)
- first bottom-dwelling, flat, slow-moving scavengers
- well developed chemoreceptors for localizing food
Lophotochozoan Protosomes
Phylumn Annelida
segmented worms
- Triploblastic, bilateral symmetry
- Earthworms, predatory marine worms, leeches
- marine worms were first annelids, and majority of existing annelids
- later annelids moved into freshwater and land
- hydrostatic skeleton and setae for burrowing in substrate
- repetition of body parts along body axis (segmentation) allowing independence of body parts
earthworms are important for cycling nutrients in ecosystems
Phylumn Annelida
Hydrostatic Skeleton
liquid inflated skeleton within annelids, aids in burrowing and locomotion
Phylumn Annelida
Setae
bumps along the body of annelids, helps with burrowing and grip
Lophotochozoan Protosomes
Phylum Mollusca
- Triploblastic, bilateral symmetry
- Chitons, snails, clams, cephalopods
- second largest phylum after arthropoda
- diverse, likely evolved from annelid ancestors
- mantle, protective shell, muscular foot, and scraping radula
- early mollusks fed on suspended and attached algae near shore
- only snails moved onto land
many used for food, some are problematic like zebra mussel
Ecdysozoan protosomes
- triploblastic, bilateral symmetry
- protosmes
- show growth via repeated shedding of the outer body exoskeleton (ecdysis)
Ecdysozoan protosomes
Phylum Nematoda
nematodes or roundworms
- triploblastic, bilateral symmetry
- occur in most habitats, including other organisms
- likely evolved from flatworm ancestor
- # of nematods > # of all other animals combined
- can tolerate extreme conditions such as over 39 years of drought, freezing/boiling, anoxia, and acidity
- primary adaptation is cuticle, which protects, prevents dehydration, and must be shed to permit growth
- play active role in nutrient cycling
- most abundant multicellular organism that feeds on bacteria and fungi in decaying plants and animals
- cause diseases like trichinosis and elephantiasis
Ecdysozoan protosomes
Phylum Arthropoda
- triploblastic, bilateral symmetry
- insects, crustaceans, spiders
- 80% of all known animal species
- evolved from annelid ancestor (segmentally arranged appendages/ bodies)
- Chitinous exoskeleton allowed for movement onto land
- Tracheae system for breathing and diffusing oxygen into body
- compound eye for spotting food from distance
70% of known animal species are types of beetles
Deuterosome Phyla
Phylum Enchinodermata
- triplobastic, radial symmetry
- closest non-chordate relative to chordates
- slow moving, omni-directional, heterotrophic
- spines for protection
- arms with gripping suction cups for locomotion and predation
Deuterosome Phyla
Phylum Chordata
- triploblastic, bilateral symmetry
- all with notochord or more
- progressively more mobile, more rigid-bodied heterotrophs
- increased cephalization
Phylum Chordata
4 key characteristics
- Notochord
- Pharyngeal gill slits
- dorsal hollow nerve cord
- post-anal tail
phylum chordata
Notochord
- fibrous support rod along the backj appearing at least during early development
- replaced by vertebral column in the adult in later evolved chordates
phylum chordata
Pharyngeal gill slits
initially used in filtering food in water, but later just for respiration
phylum chordata
Dorsal hollow nerve cord
a single dorsal nerve for rapid sensory processing
phylum chordata
post-anal tail
- a portion of tail extends posteriorly past the anus
- effective for locomotion in early evolution
Phylum Chordata
3 subphyla
- Urochordata
- Cephalochordata
- Vertebrata
Subphylum Vertebrata
6 major classes of vertebrata
- chondrichthyes
- Osteichthyes
- amphibia
- reptilia
- aves
- mammalia
Subphylum Vertebrata
Chondrichthyes
- Cartilaginous fishes (sharks and rays)
- first chordates with jaws
Subphylum Vertebrata
Osteichthyes
bony fish
Subphylum Vertebrata
Amphibia
- frogs, toads, salamanders
- first chordates to invade land
- must stay close to water
Subphylum Vertebrata
Reptilia
- lizards, snakes, turtles, and crocodiles
- dry keratinized skin for fully terrestrial
- became ruling terestrial vertebrates in mesozoic era
Subphylum Vertebrata
Aves
- birds
- flight
Subphylum Vertebrata
Mammalia
- monotremes: egg-laying
- marsupials: pouched
- placentals: with placenta
- hair and milk
