Unit 4 Flashcards
Phylum Annelida
-vermiform=worm-shaped form
-metamerism=segmentation
*homonomous with metameres=segements-essentially repeated morphologically
-setae=chaeta
-parapodia
-closed circulation
-metanephridia
-movement: crawling and swimming
-trochophore larva-found in some annelids and mollusks, shows evidence for evolutionary link between the 2
-annelids=rings
Class Polychaeta
-“many setae”
-well-developed head
-parapodia
-sandworm, tubeworm, palalo worm, fireworm
-have operculum
Class Oligochaeta
-“few setae”
-earthworms
-poorly-developed head
-clitellum
-respiration through diffusion, which requires moist skin
-no parapodia
-no/reduced eyes
-no larvae
Class Hirudinea
-“leeches”
-blood-sucking parasites
-some carnivorous
-coelom filled w/ mesenchyme
-setae usually absent
-open circulation
-clitellum present
-anticoagulant called hirudin that allows them to suck the blood without clogging it
Annelids have a very complex ______, bigger than any other animal.
Coelom
Parapodia
feet on the side, present in polychaeta, but not oligochaeta
-supported by chitinous rods
Clitellum
reproductive part of an annelid’s body that encloses the earthworm’s eggs
Phylum Arthropoda
-largest animal group
-heternomous metamerism
-tagma-head, thorax, abdomen
*exoskeleton-cuticle and epidermis, musculature (flexors and extensors), articulations
*excretory system-malpighian tubules and green gland
*respiratory systems-gills and book lungs, trachea w/ spriacles
*circulatory system-open (but surprisingly efficient), heart w/ ostia and hemocoel
*coelom is degenerate-most abundant phylum has essentially done away with a coelom in the adult form
*molting (=ecdysis) hormonal control
*compound eye-consists of ommitidium that have photoreceptors, cornea, lens
Phylum Arthropoda contains the most significant groups, especially ________, as they impacted nearly every other major group over their evolutionary history and are found in nearly every kind of habitat.
Insects
On land, plants have a love/hate relationship with arthropods as they are vital for _______ __________, but feed vocariously on plant leaves and stems (one of the main reasons plants produce so many secondary compounds is to defend themselves chemically from being eaten; these compounds represent a rich source of potential medicines).
Plant pollination
In seas, arthropods have been successful for even longer w/ representative fossils showing early ________ prescence.
Paleozoic
Heteromonous Metamerism
unlike annelids with essentially repeating segments, arthropods have combined segments into specialized regions called tagma. this specialization along w/ flexible joints (arthropod means jointed feet) has given these animals advantages in locomotion, from walking to flying to swimming.
All arthropods have tagma except for _________ and _________.
centipedes and millipedes
Most abundant skeleton is the _________.
exoskeleton
Exoskeleton is actually a _______ b/c it is produced by epidermis.
cuticle
The main component of a cuticle is ________, while some arthropods have ___________ to harden it.
chitin; calcium carbonate
Articulations are the ______ of the exoskeleton
soft parts
Ecdysone (from y-organ or prothoracic gland)->
molt
Molt-inhibiting hormone (from x-organ)->
no molting
Arthropods Classification
-appendages: biramous vs uniramous
-mouth parts-chelicerae and pedipalps vs. mandibles
-antennae
Biramous Appendages
branches into 2, consists of a series of segments
Uniramous Appendages
single series of segments attached from end-to-end
-most abundant appendage
Subphylum Trilobitomorpha
-phylum arthropoda
-extinct
-biramous
-antennae (one pair)
Subphylum Chelicerata
-phylum arthropoda
-mostly terrestrial (some marine)
-body plan: prosoma, opistoma, telson
-chelicerae (1) and pedipalps (1)
-uniramous-4 pairs
-6 pairs of appendages all together
-respiration-book lungs and gills; tracheae
-class arachnida, merostomata, and pycnogonida
Class Arachnida
-subphylum chelicerata
-terrestrial
-chelicarae w/ fangs
-web-building
Class Merostomata
-subphylum chelicerata
-aquatic
-horseshoe crabs
-giant water scorpion (extinct)
Class Pycnogonida
-subphylum chelicerata
-sea spiders
-4 leg pairs (usually)
-ovigerous legs (male)
-organs extend into legs
Subphylum Crustacea
-phylum arthropoda
-cephalothoracic segments
-thoracic segments
-abdominal segments
-cuticle hardened by calcium carbonate
-larval forms: naupilus, zoea, megalops
Cephalothoracic Segments of Subphylum Crustacea
-eye->1st antennae (antennules)->2nd antennae->1st and 2nd maxillae
Thoracic Segments of Subphylum Crustacea
-1st, 2nd, and 3rd maxillipeds->chelipeds->pereiopods (walking legs)
Abdominal Segments of Subphylum Crustacea
-pleopods (swimmerets)
-tail (telson/uropods)
Class Crustacea
-order copepoda
-order cirripedia
-order isopoda
-order decapoda
Order Copepoda
-planktonic
-abundant
-copepods
Order Cirripedia
-barnacles
-marine
-some symbiotic
-feathery/fluffy feet
Order Isopoda
-marine (except pill bugs)
-isopods
Order Decapoda
-largest group
-crabs, lobsters and shrimp
Subphylum Uniramia
-class insecta
-class chilopoda
-class diplopoda
Class Insecta
-largest animal group
-body plan-3 tagma: head, thorax, abdomen
-4 pairs of appendages-3 pairs of legs, 1 pair of mandibles
-metamorphosis and instars
-ametabolous=apterygota-bristletail and silverfish
-metabolous-pterygota
*hemimetabolous (incomplete)-exopterygota w/ nymphs-ex. grasshoppers
*holometabolous (complete)-endopterygota w/ larva, pupa w/ cocoon-ex. butterflies
As an insect matures, it undergoes _____?
molting
The intermediate molt stages prior to reaching the adult stage is sometimes called ________.
instars
Typically, there are ____ instars prior to reaching the adult stages.
5-8
Those few species that do not undergo a metamorphosis to reach the adult stage are called _________. in addition to lacking metamorphosis, they do not produce wings and are also referred to as the group ______.
ametabolous; apterygota
Most insects undergo metamorphosis and are called ________; they also have wings (at least some individuals) and are in the group __________.
metabolous; pterygota
However, some in the pterygota group undergo a partial or incomplete metamorphosis and are called _________, while others undergo a complete metamorphosis and are called _________.
hemimetabolous; holometabolous
Class Chilopoda
-subphylum uniramia
-centipedes
-poison gland
-repugnatorial gland
-carnivorous
Class Diplopoda
-subphylum uniramia
-millipedes
-diplosegment (fused pair of segments)
-poison gland
Phylum Onychophora
-a missing link?
-velvet worms
-terrestrial worms resembling annelids and arthropods
-soft cuticle
-segmented nephridia
-non-jointed appendages
-hemocoel
-trachae
-molts cuticle
-feeding appendages
Phylum Echinodermata
-deuterostomes
-marine w/ spiny skin & pentamerous (5-pointed) radial symmetry
-water vascular system w/ tube feet (podia)
Class Crinoidea
-phylum echinodermata
-sea lilies
-feather stars
-use arms for filter feeding
-abundant during the paleozoic
Class Asteroidea
-phylum echinodermata
-sea stars
-five arms (usually)
Class Ophiuroidea
-phylum echinodermata
-brittle stars
-basket stars
-central disk contains organs of reproduction, digestion and respiration
-five arms (usually)
Class Echinoidea
-phylum echinodermata
-regular echinoids-sea urchins
-irregular echinoids-sand dollars, heart urchins, sea bisquits
Class Holothuroidea
-phylum echinodermata
-sea cucumbers
-cylindrical w/ tertiary bilateral symmetry
Phylum Chaetognatha
-arrow worms
-marine planktonic predator
Phylum Hemichordata
-acorn worms
-at one time thought to possess part of a notochord (lack); thus, the prefix “hemi” does possess gill slits, which is also a chordate feature
-possess proboscis, pharyngeal slits, dorsal hollow nerve cord
Phylum Chordata
-muscles segments
-notochord
-dorsal hollow nerve cord
-mouth
-pharyngeal slits or clefts
-post-anal tail
Subphylum Urochordata
-“nonvertebrate chordate”
-tunicates and sea squirts are basically the name of the same type of animal, which consists of sessile adults w/ 2 tubes (siphons) to move water in/out of body. as larvae, these animals have tadpole-like form (tadpole larva) and possess a notochord w/in the body extending into the tail-thus, the name “uro” (tail) “chordate” (notochord).
-larvaceans are related animals that never metamorphose into sea squirts, but rather stay in larval tadpole form through a process called neoteny
-larval stage has all 4 chordate features, but adult stage only retains the pharyngeal slits
Subphylum Cephalochordata
-lancelets are streamlined animals w/ notochord that is not only found in body and tail, but also extends into head-thus the name “cephalo” (head) “chordate” (notochord)
-larval and adult stage have all 4 chordate features
Clearly, both chordates and cephalochordates are closely related to each other based on the possession of a _________. Thus, vertebrate origins are linked to these 2 groups.
Notochord
The fossil record supports the assumption that the prototypical 1st vertebrate was likely a fish-type animal called the ___________.
Pikaia
Larvaceans result from a process called ________ which basically means when a juvenile/larval type form through mutation possess the ability to reproduce
paedomorphosis (paedogenesis)
Somatic Tissues
non-reproductive tissues, such as the muscles, bone, and skin
Germinal Tissues
reproductive tissues, such as the ovaries and testes
Paedomorphosis can occur in 2 ways: _______ and _______.
Neoteny and Progenesis
Neoteny
somatic tissues slow down relative to the germinal tissues during development
Progenesis
germinal tissues speed up relative to the somatic tissues during development
In humans, if neoteny occurs during development, the bones and tissues will not reach their normal adult size/mass, but the gonads will continue their normal rate of development. This means that a child reaching puberty may be considerably smaller but can still reproduce. This is called ________.
Dwarfism
If a child’s gonads accelerate in development, but the somatic tissues develop at the normal rate, then sexual maturity can be reached as early as ___.
5 y/o
One very important endocrine gland called the ________ is extremely important in development/metamorphosis in many vertebrates and is potentially impacted in paedomorphic scenarios.
Thyroid gland