Midterm 2 All Flashcards

-Multicellular eukaryotes
-Heterotrophs
-Cells lack cell walls
-Collagen

What is an animal?

-comprises fibers in connective tissues
-most abundant protein in animal bodies
-flexible, high tensile (stretchy), strength, high elastic resilience (returns energy)

What is collagen?

-skin: dense irregular arrangement of collagen
-ligament (connect bones): collagen arranged in sheets
-tendon (connects muscles to bones): cable-like arrangement of collagen

What are the different collagen arrangements?

-sexually with diploid stage dominating the life cycle
-sperm fertilizes egg → zygote
zygote undergoes rapid cell division → cleavage

How do animals reproduce?

-collections of specialized cells with a common function, isolated from other tissues by membranous layers

What are tissues?

-germ layers give rise to the tissues and organs of the animal embryo

What are germ layers?

-cell cleavage

What leads to a blastula?

-hollow blastula undergoes gastrulation
-forms a gastrula with layers of embryonic tissues

What undergoes gastrulation and what does it form?

-ectoderm: covers embryo's surface
-endoderm: innermost germ layer and lines the developing digestive tube →archenteron
-archenteron

What are the different embryonic tissue layers in a gastrula?

-sponges

What animals lack true tissues?

-have ectoderm and endoderm
-coral, jellyfish, comb jellies

What are diploblastic animals and give some examples.

-have ectoderm, endoderm, and mesoderm layer (in between ectoderm and endoderm)

What are triploblastic animals?

-multicellular animals other than sponges and cnidarians
-Characteristics: bilateral symmetry, cephalization (organization of senses and locomotion toward a head region)

What are bilaterians and what are some of their characteristics?

-larva: sexually immature and anatomically distinct from an adult; undergoes metamorphosis
-juvenile: resembles an adult but is not sexually mature

What are some characteristics of a larval stage?

-(535 to 525 million years ago) marks the earliest fossil appearance of many major groups of living animals
-new predator-prey relationships
-rise in atmospheric oxygen
-evolution of the Hox gene complex

What is the Cambrian explosion and what are some possible causes?

-regulate other genes and control the development of body form

What are Hox genes?

-deuterostomes
-lophotrochozoa
-ecdysozoa

What are the three major groups that separate bilateral animals?

-cell proliferation following fertilization by spiral cleavage
-coelom (body cavity) forms within the middle tissue germ layer
-initial opening into the gut becomes the mouth

What is a protostome?

-cell proliferation following fertilization by radial cleavage
-coelom forms from outpocketing of the middle tissue germ layer
-initial opening into the gut becomes the anus

What is a deuterostome?

-smallest genome
-only four cell types
-no symmetry
-no organs
-no muscles
-no nervous system

What are the characteristics of the phylum placozoa?

-sponges
-Characteristics: specialized cell types but no true tissues; sessile → no locomotion; collar cells → responsible for movement, in flagella, create water currents that move through the body of the sponge

What are some characteristics of the phylum porifera and give an example of an animal in this phylum.

-tiny calcium or silica structures
-support sponge body

What are spicules and what animal has them?

-function in digestion of food particles pulled from the water current by the collar cells

What are amoebocytes?

-modern choanoflagellates → protists

What does the hypothesized ancestor responsible for animal diversity resemble?

-sponges
-sperm is released into the environment

What are hermaphrodites and what animal is one?

-jellyfish, anemones, corals
-radial symmetry
-two specialized cell layers (tissues)
-nerve cells
-feeding is done by capturing food particles or prey from water

What are some characteristics of the phylum cnidaria and what are some animals in this phylum?

-sessile polyp
-free-swimming medusa

What are the two body forms for cnidarians?

-way to get prey by launching a venomous spine

What is a nematocyst?

-lophophore: horse-shoe shaped feeding structure or
-trocophore: ciliated larva

What are characteristics of the lophotrochozoa?

-flatworms
-lack circulatory, respiratory, and skeletal systems
-coelom is absent and gut is incomplete
-large range in size (less than 1 mm to several m)

What are characteristics of the phylum platyhelminthes and what are some examples of this phylum?

-turbellaria
-monogenea
-trematoda
-cestoda

What are some of the classes of the phylum platyhelminthes?

-mostly marine, some fresh water, a few terrestrial
-predators and scavengers
-body surface is ciliated
-mostly hermaphordites but can also reproduce asexulally
-flatworms, planarian

What are some characteristics of the class tubellaria and what are some animals in this class?

-marine and freshwater parasites
-most infect external surfaces of fishes (skin and gills)
-life history is simple
-ciliated larva starts infection on host
-unciliated synctial outer layer (cells connected so that cytoplasm is shared
-monogeans

What are some characteristics of the class monogea and what are some animals in this class?

-parasites, mostly vertebrates
-two suckers attach to host (mollusc and vertebrate)
-most life cycles include intermediate and finals hosts
-infections from this class can cause pain, anemia, dysentery, and liver damage
-trematodes (flukes)

What are some characteristics of the class trematoda and what are some animals in this class?

-parasites of vertebrates
-scolex (hooked structure) attaches to host (via intestine)
-proglottids produce eggs and break off after fertilization
-no head, digestive system, and no sense organs
-life cycle with one or more intermediate hosts
-proglottids → comprise the body and contains both male and female sex organs
-tapeworms

What are some characteristics of the class cestoda and what are some animals in this class?

-Rotifer
-max size is 3mm (super small)
-wide range of aquatic and marine habitats
-some can survive in extremely dry and cold conditions
-predators, parasites, filter feeders (some are sessile)
-mouth has hard, muscular jaws
-have separate sexes or are asexual

What are some characteristics of the phylum syndermata and an example of an animal in this phylum?

-need moisture in habitat, but has a huge range of habitats
-large variety of sizes
-one of the largest animal phyla
-used as food, crop pests, and intermediate hosts for human parasites
-protective mantle enclosing a mantle cavity and muscular foot
-radula → scraping, tongue-like feeding organ; in all major mollusc classes except bivalves

What are some characteristics of the phylum mollusca?

-calcium carbonate

What are mollusc shells composed of?

-polyplacophora
-gastropoda
-bivalvia
-cephalopoda

What are some of the classes of the phylum mollusca?

-marine
-shell with 8 plates
-foot used for locomotion
-radula
-no head
-chitons

What are some characteristics of the class polyplacophora and what are some animals in this class?

-marine, freshwater, or terrestrial
-head present
-symmetrical body, usually with a coiled shell
-shell reduced or absent
-foot for locomotion
-radula
-mostly herbivores but some are scavengers or active predators
-some have a complex genital apparatus from the side of its head which hermaphroditic slugs use to pass sperm
-some snails have "love darts" to inject hormones into their mate to increase the success of their sperm in fertilizing eggs
-snails, slugs

What are some characteristics of the class gastropoda and what are some animals in this class?

-marine and freshwater
-flattened shell with two valves
-head reduced
-paired gills → modified for filter-feeding
-no radula
-locomotion is by extension and anchoring of the foot or by propelling water between the valves (shells)
-clams, mussels, scallops, oysters

What are some characteristics of the class bivalvia and what are some animals in this class?

-marine predators
-head surrounded by grasping tentacles, usually with suckers
-shell external, internal, or absent
-mouth with or without radula
-locomotion via jet propulsion; foot is modified into a siphon for propulsion
-sexes are separate
-highly developed nervous and sensory systems
-squids, octopuses, cuttlefishes, chambered natiluses

What are some characteristics of the class cephalopoda and what are some animals in this class?

-true coelom
-closed circulatory system
-body plan exhibits distinct repetition of segments → metameric
-reproduction by separate sexes, hermaphroditic sexual reproduction, or by fission and regeneration
-marine

What are some characteristics of the phylum annelida?

-errantia
-sedentaria

What are the two major clades of the phylum annelida?

-mostly mobile and marine
-pair of paddle/ridge-like parapodia (beside feet) on each body segment
each parapodium (foot) has numerous chaetae → bristles made of chitin

What are some characteristics of the clade errantia?

-less mobile than errantians
-some burrow into substrate or live in protective tubes
-tube-dwelling sedentarians have elaborate gills or tentacles used for filter feeding
-leeches and earthworms

What are some characteristics of the clade sedentaria?

-parasites/predators
-lack chaetae and have suckers on anterior and posterior ends
-blood-sucking leeches produce an anti-clotting enzyme, hirudin, to facilitate feeding

What are leeches?

-ecdysis → periodic shedding of a cuticle

What is a defining characteristic of the ecdysozoa?

-cuticle → non-living external layer secreted by the epidermis
-cuticle is periodically shed as the nematode grows → ecdysis
-only have longitudinal muscles
-hydrostatic skeleton → resists compression and transmits muscular forces due to the high internal pressure in the pseudocoelom allowing it to function with the cuticle

What are some characteristics of the phylum nematoda?

-ascaris lumbricoides
-necator americanus (hookworm)
-trichinella spiralis
-caenorhabditis elegans

What are some animals that are part of the phylum nematoda?

-largest and most common parasite of the human intestine
-one female can lay over 200,000 eggs each day
-intestinal infection is acquired by ingesting eggs present in the soil

What are some characteristics of ascaris lumbricoides?

-juveniles feed on bacteria in the soil and infect humans by penetrating the skin
-adults feed on blood sucked from the lining of the intestines

What are some characteristics of necator americanus (hookworm)?

-responsible for the potentially lethal disease trichinosis contracted by consuming undercooked pork
-juveniles enter muscle cells and alter the host's gene expression to change the muscle into a nurse cell that protects and nourishes the nematode

What are some characteristics of trichinella spiralis?

-most studied "model organisms"

What are some characteristics of caenorhabditis elegans?

-tropical predators that prey on ground-dwelling insects, snails, and worms
-unjointed appendages and a body form that changed very little
-paired slime glands spray an entangling fluid to catch prey
-onychophorans or velvet worms

What are some characteristics of the phylum onychophora?

-water bears; microscopic inhabitants of water films on mosses or marine sands that feed by sucking fluids from other tiny animals or plants
-cryptobiosis → state of suspended metabolism
-in cryptobiotic state, tardigrades can survive: heating to 149°C and cooling to -272°C; radiation; lack of oxygen

What are some characteristics of the phylum tardigrada?

-cuticle hardened by proteins
-exoskeleton made of chitin
-jointed appendages that are modified for special functions
-segmented bodies into functional units → tagmata
-open circulatory system emptying into body cavity → hemocoel
-complete digestive system, complex muscle and nervous systems
-respiration through a complex system of air canals → trachea

What are some characteristics of the phylum arthropoda?

-cheliceriformes
-myriapoda
-hexapoda
-crustacea

What are some of the subphyla of the phylum arthropoda?

-body having one or two main parts
-six pairs of appendages
-mostly terrestrial or marine
-horseshoe crabs, spiders, scorpions, ticks, mites

What are some characteristics of the subphylum cheliceriformes and what are some animals in this subphylum?

-distinct head bearing antennae and chewing mouthparts
-terrestrial
-millipedes and centipedes

What are some characteristics of the subphylum myriapoda and what are some animals in this subphylum?

-body divided into head, thorax, and abdomen
-antennae present
-three pairs of legs and usually two pairs of wings
-mostly terrestrial
-insects, springtails

What are some characteristics of the subphylum hexapoda and what are some animals in this subphylum?

-body of two or three parts
-antennae present
-chewing mouthparts
-three or more pairs of legs
-elaborate serial homology
-mostly marine and freshwater
-crabs, lobsters, crayfishes, shrimps

What are some characteristics of the subphylum crustacea and what are some animals in this subphylum?

-study of insects is called entomology
-openings in the exoskeleton lead to a system of trachea and tracheoles that supply the body with oxygen
-growth in insects result in molting of exoskeleton; the life stages between molts are called instars
-has the protein resilin which plays a large role in locomotion
-flexible chitinous exoskeleton
-asynchronous flight muscles

What are some characteristics of insects?

-ametabolous: growth without major change in form
-hemimetabolous: nymph stage is followed by increased development of wings from buds with each successive molt
-holometabolous: complete metamorphosis from stages specialized for feeding to stages specialized for mating and dispersal

What are the three stages of insect development?

-hemichordata
-echinodermata
-chordata

What phylums are classified as deuterstomes?

-asteroidea
-ophiuroidea
-echinoidea
-crinoidea
-holothuroidea

What are some classes in the phylum echinodermata?

-marine animals
-secondarily evolved radial symmetry from a bilateral ancestor (larva are still bilateral)
-calcium-containing endoskeleton (internal skeleton) of plates or tiny bony elements
-none of the echinoderms are parasites
-water-vascular system for movement
-fluid is pushed from muscular ampullae into tube feet causing them to extend
-external surface is covered with spines and pedicellariae → tiny jaws that keep the surface clear of debris and parasites
-catch collagen → unique connective tissue of echinoderms, changes rapidly between solid and liquid states in response to stimulation from the nervous system

What are some characteristics of the phylum echinodermata?

-star-shaped body with multiple arms
-mouth directed to substrate
-sea stars

What are some characteristics of the class asteroidea and what are some animals in this class?

-distinct central disk
-long, flexible arms
-incomplete digestive system
-brittle stars

What are some characteristics of the class ophiuroidea and what are some animals in this class?

-roughly spherical or disk-shaped
-no arms
-five rows of tube feet
-mouth ringed by complex, jaw-like structure
-sea urchins, sand dollars

What are some characteristics of the class echinoidea and what are some animals in this class?

-feathered arms surrounding upward-pointing mouth
-sea lilies, feather stars

What are some characteristics of the class crinoidea and what are some animals in this class?

-cucumber-shaped body
-five rows of tube feet
-reduced skeleton
-no spines
-secondarily evolved bilateral symmetry
-can digest organic matter in sediment and can expel and regenerate their digestive system
-sea cucumbers

What are some characteristics of the class holothuroidea and what are some animals in this class?

-notochord → semi-rigid rod of cells enclosed by a fibrous sheath that functions as a skeletal element
-dorsal, hollow nerve cord → runs along the length of the body
-pharyngeal slits or clefts → openings in the pharyngeal cavity (throat) to the outside of the animal; leads to the structures of the middle ear, tonsils, and internal gills
-muscular, post-anal tail → aquatic locomotion

What are the characteristics of the phylum chordata?

-cephalochordata
-urochordata

What are the two chordate lineages that diverged early in the evolution of vertebrates?

-lancelets
-small, thin filter-feeders
-found on the sandy bottoms in coastal waters
-lack gills and heart
-closed circulatory system

What are some characteristics of the cephalochordates?

-also known as tunicates
-more closely related to other chordates than lancelets
-as an adult, draws in water through an incurrent siphon which filters food particles

What are some characteristics of the urochordata?

-backbone
-two or more sets of hox genes that regulate anterior-posterior development
-embryos have neural crest cells that give rise to a variety of structures (bones, cartilage)

What are some characteristics of vertebrates?

-Scavengers: myxini, hagfish, petromyzontida
-Parasites: lampreys

What are some examples of jawless fish (cyclostomes)? Which ones are scavengers and which ones are parasites?

-notochord is the only "backbone"
-cartilage braincase rather than bone
-no paired fins
-no stomach
-partially open circulatory system (4 hearts)

What some characteristics of the myxini?

-fibrous and cartilage skeleton
-cartilage braincase
-no paired fins
-distinct stomach
-closed circulatory system with single heart

What are some characteristics of the petromoyzontida?

-glands that secrete huge amounts of mucous and protein threads that surround the body in defensive slime

What are some characteristics of hagfishes?

-attach to fish by suction and rasp a wound through the skin with their spiny tongues
-anticoagulant allows lamprey to acquire blood and body fluids while attached to the host

What are some characteristics of lampreys?

-chordates with jaws
-sharks, ray-finned fish, lobe-finned fish, amphibians, reptiles (including birds), mammals
-placoderms → earliest gnathostomes in fossil records

What are gnathostomes and what are some examples?

-improved respiratory efficiency (closing jaws prevents backflow when water is passed over the gills)
-grasping, biting, suction feeding
-may have evolved from the skeletal supports of the pharyngeal slits

What is the significance of jaws?

-aka chondrichthyes
-skeleton composed primarily of cartilage
-sharks, rays, skates
-lack of mineralization in the cartilage skeleton
-calcified bony skeletal elements
-scales are a type of placoid → form horns, spines, teeth
-spiral valve → slows passage of food and increases surface area for absorption
-males have claspers → modified pelvic fins for copulation
-oviparous, ovoviviparous, viviparous

What are some characteristics of the chondrichthyans?

-eggs hatch outside the mother's body

Define oviparous.

-embryo develops within the uterus and is nourished by the egg yolk

Define ovoviviparous.

-embryo develops within the uterus and is nourished through a yolk sac placenta from the mother's blood

Define viviparous/

-bony fish, tetrapods
-bone replaces cartilage in the skeleton
-operculum → plate-like, covers gills and allows fish to breathe efficiently without forward movement
-gills maximize surface area for gas exchange by having folding on multiple levels
-more diverse teeth and digestive systems than chondrichthyes
-gas bladder increased swimming efficiency and maneuverability by contributing to neutral buoyancy

What are some characteristics of the osteichthyans?

-lateral line → "distant touch" detection of water movements via neuromasts
-neuromasts have extensions that trigger signals to the nervous system when displaced by water movement
-lateral lines are arranged on the head and along the side of the body

What are is a shared characteristics between the chondrichthyes and osteichthyans?

-osteichthyans that share some characteristics of the first terrestrial vertebrates
-coelacanth → paired fins at the end of appendages with internal bony elements, notochord as the primary anterior-posterior support, jointed braincase

What are lobe-fins? (characteristics, significance)

-notochord
-developed vertebrae
-functional lungs
-withstand drying of their habitat
-estivation → state of reduced physiological activity during drought (air-breathe, lower heart rate, retain urea and other wastes, break down body fat and protein)

What are some characteristics of lungfish?

-ancestrally terrestrial and four-limbed vertebrates
-amphibia

What are tetrapods?

-oxygen is more concentrated in air than in water
-air is less dense and less thick than water
-air experiences far greater temperature extremes
-terrestrial environments comprise greater diversity of habitats than marine environments

What are some difference between marine life and terrestrial life?

-skeleton is mostly bone
-usually have four limbs
-skin is moist and functional in respiration (oxygen and carbon dioxide diffuse across skin)
-mucous glands that keep skin moist so it functions as a respiratory surface (cutaneous respiration), produce adhesives that function in locomotion and defense
-skin can produce caustic and toxic poisons
-aquatic larva and terrestrial adult
-frogs, salamanders, caecilians

What are some characteristics of amphibians?

-elongate, tailed, four limbs (except for some fully aquatic forms)
-larvae have external gills and laterally flattened tails
-most fully terrestrial salamanders hatch from eggs as miniatures of the adult with no aquatic larval stage
-paedomorphosis → evolution of retention of larval characteristics into adulthood (many reach sexual maturity while retaining external gills and an aquatic habitat)
-may have gills, lungs, both, or neither

What are some salamander characteristics?

-most eggs are fertilized internally by sperm passed to the female in a packet or spermatophore
-eggs are either deposited on the spermatophore or it is drawn into the female's cloaca
-few species are viviparous (birth live young)

How do salamanders reproduce?

-warning (aposomatic) coloration
-poison that is fast acting on lips or epithelial tissue of mouth to rapidly deter predation

What are some defensive and offensive options that salamanders have?

-skeletal features specialize anurans for locomotion by jumping with hindlimbs generating the power to propel the frog through the air or water
-pelvis is elongate and reaches far anteriorly and the posterior vertebrae are fused into a urostyle
-vertebral column is short and overlapping projections restrict side to side bending
-closed circulatory system with a three-chambered heart and separate pulmonary and systemic circuits
-external fertilization with eggs deposited in aquatic habitats
-larval tadpole have external then internal gills with the full process of metamorphosis taking 2-3 years in some species

What are some characteristics of frogs?