animal diversity Flashcards
Diplontic life cycle
refers to the life cycle of organisms, which is dominated by the diploid stage
Asymmetry
lack symmetry altogether
EX: sponges
Radial symmetry
symmetry in which the body is shaped like a pie or barrel (lacking a left side and a right side) and can be divided into mirror-imaged halves by any plane through its central axis
ex: flower pot or sea anemone
Oral-aboral axis
radially symmetrical cnidarians have multiple planes of symmetry
- with this they only have a single body axis - the oral-aboral axis
- these organisms have their mouth on the ORAL surface & their opposite side is the ABORAL side
Bilateral symmetry
a central longitudinal plane divides the body into 2 equal but opposite halves
ex: shovel or lobster
Cephalization
an evolutionary trend toward the concentration of sensory equipment at the anterior (head) end of the body
Anterior-Posterior axis
anterior: front
posterior: rear
Dorsal-Ventral axis
dorsal: top
ventral: bottom
True Tissue
in animals, true tissues are collections of specialized cells isolated from other tissues by membranous layers
- sponges and a few other groups lack true tissues
Diploblastic
having 2 germ layers
Triploblastic
possessing 3 germ layers: the endoderm, mesoderm, and ectoderm
- most eumetazoans are triploblastic
Endoderm
the innermost germ layer, lines the pouch that forms during gastrulation (the archenteron) and gives rise to the lining of the digestive tract (or cavity) and organs such as the liver and lungs of vertebrates
Mesoderm
which fills much of the space between the ectoderm and endoderm
- in a triploblastic, bilaterally symmetrical, animals
Ectoderm
the outermost germ layer covering the surface of the embryo, gives rise to the outer covering of the animal and, in some phyla, to the central nervous system
Coelom
a body cavity lined by tissue derived only from mesoderm
- it’s a space that opens up within the mesoderm (which means all coelomates are triploblasts) that cushions and protects the organs, provides the stiffness in hydrostatic skeletal systems, and has been lost in some lineages (which means not all triploblasts are coelomates).
Acoelomate
a solid-bodied animal lacking a body cavity between the gut and outer body wall
Pseudocoelomate
animals with only a hemocoel
(Eu)coelomate
an animal that has a true coelom (fluid filled body cavity) which surrounds the gut and is lined on both sides by mesoderm
Segmentation
segments are when a body plan has repeated body sections
- in Annelids, Arthropods and Chordates
Protostome
in animals, a developmental mode distinguished by the development of the mouth from the blastopore; often also characterized by spiral cleavage and by the body cavity forming when solid masses of mesoderm split
EX: molluscs, annelids
Spiral cleavage
a type of embryonic development in protosomes in which the planes of cell division that transform the zygote into a ball of cells are diagonal ot the vertical axis of the embryo. As a result, the cells of each tier sit in the grooves between cells of adjacent tiers
Determinate development
of some animals with protostome development rigidly casts (“determines”) the developmental fate of each embryonic cell very early
- a cell isolated from a snail at the four-cell stage, for example, cannot develop into a whole animal
- instead, after repeated divisions, such a cell will form an inviable embryo that lacks many parts
Schizocoely
in protostomes, part of the mesoderm separates to form the coelom in a process called schizocoely
Deuterostome
in animals, a developmental mode distinguished by the development of the anus from the blastopore; often also characterized by radial cleavage and by the body cavity forming as out-pockets of mesodermal tissue
EX: echinoderms, chordates
Radial cleavage
a type of embryonic development in deuterostomes in which the planes of cell division that transform the zygote into a ball of cells are either parallel or perpendicular to the vertical axis of the embryo, thereby aligning tiers of cells one above the other
Indeterminate development
meaning that each cell produced by early cleavage divisions retains the capacity to develop into a complete embryo
ex: if the cells of a sea urchin embryo are separated at the four-cell stage, each can form a complete larva
- similarly, this in the human zygote that makes identical twins possible
Enterocoely
in deuterostome animal embryo develop, the mesoderm pinches off of the digestive tract to form the coelom in a process called enterocoely.
Invertebrates
an animal without a backbone (makes up 95% of animal species)
Vertebrates
a chordate animal with a backbone, including sharks and rays, ray-finned fishes, coelacanths, lungfishes, amphibians, reptiles, and mammals
Mesohyl
a gelatinous region between the 2 layers of cells in a sponge (“middle matter”)
- b/c both cell layers are in contact with water, processes such as GAS EXCHANGE and WASTE REMOVAL can occur BY DIFFUSION across the membranes of these cells
Choanoderm
a type of cell layer composed of flagallted collar cells, or choanocytes, found in sponges
Pincaocytes
one of the flat cells covering the external surface and lining the incurrent and excurrent canals of sponges are part of the epithelium in sponges
- they play a roll in MOVEMENT (contracting and stretching, cell adhesion, signalling, phagocytosis, and polarity
- are filled with mesophyl
Choanocytes
a flagellated feeding cell found in sponges
- also called collar cell, it has a collar-like ring that traps food particles around the base of its flagellum
Amoebocytes
an amoeba-like cell that moves by pseudopodia and is found in most animals
- depending on the species, it may digest and distribute food, dispose of wastes, form skeletal fibres (spicules), fight infections, or change into other cell types
Spicules
tough sharp skeletal fibres made of calcium carbonate or silica; which can be produced by amoebocyte cells
- found in porifera/sponges
Totipotent
they can differentiate into other types of sponge cells, like stem cells
- this gives the sponge body remarkable flexibility, enabling it to adjust its shape in response to changes in its physical environment (such as the direction of water currents)
- basically can transform into any cell type that is needed by the body
Pluripotent
describing a cell that can give rise to many, but not all, parts of an organism
Multipotent
have the ability to form multiple types of cells
Gastrovascular cavity
a central cavity with a single opening in the body of certain animals, including cnidarians and flatworms, that functions in both the digestion and distribution of nutrients
Complete gut
digestive tract, which is a group of tissues or organs designed to break down food
Epidermis
the OUTMOST layer of cells in an animal of CNIDARIANS; derived from ECTODERM
- have bundles of mircofilaments arranged into contractile fibres
Mesoglea
gelatinous layer between the epidermis and gastrodermis
Gastrodermis
the INNERMOST layer of cells in an animal of CNIDARIANS
- have bundles of microfilaments arranged into contractile fibres
Polyp
the sessile variant of the cnidarian body plan
- are cylindrical forms that adhere to the substrate by the aboral end of their body (the end opposite the mouth) and extend their tentacles, waiting for prey
EX: hydras and sea anemones
Medusa
the floating, flattened, mouth-down version of the cnidarian body plan
- it moves freely in the water by a combination of passive drifting and contractions of its bell-shaped body
EX: free-swimming jellies
Cnidocyte
a specialized cell unique to the phylum Cnidaria; contains a capsule-like organelle housing a coiled thread that, when discharged, explodes outward and functions in prey capture or defence
Super organism
is a group of synergetical interacting organisms of the same species
Gastrozooid
2 types of polyps:
the first is gastrozooid, which is adapted for capturing prey and feeding
Dactrozooid
a tentacular mouthless zooid in certain hydrozoans that performs tactile and protective functions for the colony.
Autozooid
a zooid that is able to feed.
Gonozooid
are any of the reproductive individuals of Tunicates, Bryozoan, or Hydrozoan colonies that produce gametes.
Blastropore
in a gastrula, the opening of the archenteron that typically develops into the anus in deuterostomes and the mouth in protostomes
Pentaradial symmetry
for the ECHINODERMS:
- larvae = bilateral symmetry
- adults = pentaradial symmetry (acquired during metamorphosis)
- in pentaradial symmetry, there are exactly 5 planes of symmetry
exception: sea cucumbers
Water vascular system
the COELOM of the ECHINODERMS has been modified into this which is unique to echinoderms that branches into extensions called TUBE FEET, which function in LOCOMOTION & FEEDING
- also used for SENSATION and/or GAS EXCHANGE
Notochord
a longitudinal, flexible rod made of tightly packed mesoderm cells that runs along the anterior posterior axis of chordate in the dorsal part of the body, for muscle attachment and support
- in humans, only in early development and releases growth factors and goes away (not used for structure)
Pharyngeal gill arches/slits
in chordates embryos, one of the slits that form from pharyngeal clefts and communicate to the outside later developing into gill slits in many vertebrates:
- filter-feeding organs
- water goes through and the gills just grab whatever food is available in the water
- in humans it goes away after
Post-anal tail
in chordates:
- it is a muscular tail that extends posterior to the anus, contains skeletal elements and muscles helps propel many aquatic species
- have a tail that extends posterior to the anus, although in many species it is greatly reduced during embryonic development
- in humans it goes away
Dorsal, hollow nerve cord
in chordates:
- develops from a plate of ectoderm that rolls into a tube located dorsal to the notochord
- unique to chordates
- connects brain with basically all other tissue
- the nerve cord of a chordate embryo develops into the central nervous system: the brain and spinal cord
Jaws (jawed vertebrates)
gnathostomes (“jaw mouth”) are named for their jaws, hinged structures that, especially with the help of teeth, enable gnathostomes to grip food items firmly and slice them
- clade of the phylum chordata
- 3 groups:
1. Rays & Sharks (“cartilaginous”)
2. Ray-finned fishes (“boney” ex: trout, salmon, goldfish etc. any fish really
3. Lobe-finned fishes
a. coelacanth - deep sea animals
b. lungfishes - have lungs & breath like we do
3rd is tetrapods (not really fish)
- amphibians, reptiles (including birds), and mammals
Cartilaginous (Fish)
- is a class of the phylum chordata
- Sharks, Rays, and Ratfishes
- skeletal rods (cartilaginous “bones”) modified into jaws
- vertebrae filled out to make a complete skeleton:
- still only cartilaginous (softer & flexible)
- provides still structure for bigger muscles and improved swimming
- provides protection to nervous system - electrical sensation
- lateral line
Boney (Fish)
- a class of the phylum chordata
- ray-finned fish
EX: trout, salmon, goldfish, salamanders, etc. (any fish) - true bones (calcium phosphate-based)
- better protection to nervous system
- can accomodate even bigger, more powerful muscles
- improves swimming even more
- SWIM BLADDER
- a “lung derivative” (air pocket)
- improves buoyancy, & thus swimming ability
- OPERCULUM
- protects gills
- allows breathing without swimming
Limbs
an arm or leg of a person or four-legged animal, or a bird’s wing.
Amnion
encloses a compartment of fluid that bathes the embryo and acts as a hydraulic shock absorber
Mammary gland
an exocrine gland that secretes milk to nourish the young
- mammary glands are characteristics of mammals
Continuous growth
lophotrochozoa grow continuously
- juveniles (the life cycle stage after larvae that look similar to adults) gradually get larger until they reach their adult size
Lophophore
in some lophotrochozoan animals, including brachiopods, a crown of ciliated tentacles that surround the mouth and function in feeding
Trochophore
distinctive larval stage observed in some lophotrochozoan animals, including some annelids and molluscs
Free-living
free-living rhabditophorans are important as predators and scavengers in a wide range of freshwater and marine habitats
- the best-known members of this group are freshwater species in the genus Dugesia, commonly called planarians
Parasitic
more than half of the known species of rhabditophorans live as parasites in or on other animals
- many have suckers that attach to the internal organs or outer surfaces of the host animal
- in most species, a tough covering helps protect the parasites within the host
- reproductive organs occupy nearly the entire interior of these worms
- 2 important subgroups of parasitic rhabditophorans
- trematodes
- tapeworms
Muscular foot
1 of the 3 main parts of a mollusc; a muscular structure usually used for movement/locomotion
Visceral mass
1 of the 3 main parts of a mullusc; the part containing most of the internal organs
Mantle
1 of the 3 main parts of MOST mollusc; a fold of tissue that drapes over the mullusc’s visceral mass and may secrete a shell (exoskeleton)
- it is NOT shed (they just add on as necessary)
Mantle cavity
a water-filled chamber that houses the gills, anus, and excretory pores of a mollusc
Radula
a straplike organ used by many molluscs during feeding to scrape food
Chromatophores
?? are pigment-containing cells, or groups of cells, found in a wide range of animals including amphibians, fish, reptiles, crustaceans and cephalopods. ??
Parapodia
(beside feet) a pair of prominent paddle like or ridge like structures
Palps
a pair of appendages, that function in sensing, feeding, or reproduction
- food particles suspended in water enter through the incurrent siphon are collected by the gills and passed to the mouth by palps and cilia
Cuticle
the exoskeleton of an arthropod, consisting of layers of protein and chitin that are variously modified for different functions
- a tough coat that covers the body of a nematode
- must be shed as animal grows (a process called “ecdysis”) AKA molting exoskeleton
Exoskeleton
a hard encasement of the surface area of an animal, such as the shell of a mollusc or the cuticle of an arthropod, that provides protection and points of attachment for muscles
Step-wise growth
ecdysozoa (ex: nematodes & arthropods) grow by spurts in a stepwise pattern
- they are covered by a cuticle (hardened covering), which prevents continual growth
- in order to grow, these animals must periodically shed this cuticle (molt) & grow rapidly before creating a new one
Moulting
a process in ecdysozoans in which the exoskeleton is shed at intervals, allowing growth by the production of a larger exoskeleton
Uniramous
It consists of an unbranched series of segments (for anthropod leg).
Biramous
dividing to form two branches (for anthropod leg).
Chelicera
1 of a pair of clawlike feeding appendages, characteristics of chelicerates
Tagma
arthropod segments have also fused together into functional units called tagma. This process of segment fusion, or tagmosis, usually results in an arthropod body that consists of three major sections, a head, thorax, and abdomen
Head
of the arthropods, specifically Chelicerates
Thorax
of the arthropods, specifically Chelicerates
Cephalothorax
head + thorax
Abdomen
a lot of gut, typically no appendages off the abdomen
Complete metamorphosis
the transformation of a larva into an adult that looks very different, and often functions very differently in its environment, than the larva
Incomplete metamorphosis
a type of development in certain insects, such as grasshoppers, in which the young (called nymphs) resemble adults but are smaller and have different body proportions.
- the nymph goes through a series of moults, each time looking more like an adult, until it reaches full size
Explain the evidence of shared ancestry between the animals and choanoflagellates.
- Morphologically, choanoflagellate cells and the collar cells (or choanocytes) of sponges are almost indistinguishable.
- Similar collar cells have been identified in other animals, including cnidarians, flatworms, and echinoderms-but they have never been observed in non-choanoflagellate protists or in plants or fungi.
- DNA sequence data indicate that choanoflagellates and animals are sister groups. In addition, genes for signalling and adhesion proteins previously known only from animals have been discovered in choanoflagellates.
page 715 fig 32.3
