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63 Cards in this Set
- Front
- Back
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characteristics of animals
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multicellularity, heterotrophic, sexual reproduction, cells lack a cell wall, mobile at some point, quick responses to external stimuli
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scientists examine these features to understand evolutionary history
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anatomy, embryological development, DNA sequences
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these features represet evolutionary milestones
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the appearance of tissues,
the appearance of body symmetry, protostome and deuterostome development |
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tissues
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groups of similar cells that carry out a specific function
the earliest animals had no tissues sponges are the only modern day animal that lack tissues |
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radial symmetry
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-can be divided into roughly equal halves by any plane through the central axis
-tend to be either sessile (fixed together in one spot) or drift on currents |
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ectoderm
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outer layer that covers the body,
lines its inner cavities, forms the nervous system |
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endoderm
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inner layer which lines most hollow organs
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sessile
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fixed together on one spot
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bilateral symmetry
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can be divided into mirror-image halves only along one plane that runs down the midline
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animals with bilateral symmetry
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have mesoderm (layer b/w endo and ectoderm),
exhibit cephalization with definite anterior and interior regions, tend to move forward most have cavities |
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cephalization
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the concentration of sensory organs and a brain in a well-defined head
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coelomate animals
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possess a coelom (a fluid filled body cavity that is completely lined with mesoderm)
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pseudocoelomate animals
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possess a pseudocoelom (a fluid-filled body cavity that is NOT completely lined with mesoderm)
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bilateral animals can be divided between:
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protostomes and deuterostomes
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protostomes
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body cavity forms within a space between the body wall and the digestive cavity
ex. mollusks, flatworms, nematodes, arthropods, annelids |
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deuterostomes
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body cavity forms as an outgrowth of digestive cavity
ex. echinoderms, chordates |
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ecdyzsozoans
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have bodies covered by an outer layer that is periodically shed
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lophotrochozoans
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have a lophophore (special feeding structure) or pass through a trocophore larva developmental stage
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invertebrates
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lack a vertebral column,
can have internal skeleton to support weight, |
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vertebrates
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have a vertebral column
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water --> land adaptations
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lay eggs outside of water, lungs, feet
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annelids
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bilateral symmetry,
coelomate, repeating units of segmentation, closed circularoty system |
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benefit of closed circulatory system?
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means: blood confined to heart and blood vessels
purpose: distributes gases and nutrients throughout body |
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annelid digestion compartments
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pharynx- draws in food
esophagus- conducts food to crop crop- stores food gizzard- grinds food intestine- absorbs digested nutrients |
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3 species of Annelids
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oligochaetes,
polychaetes, leeches |
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oligochaetes
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live in moist terrestrial habitats, e.g. eathworms
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polychaetes
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all are marine, some live in tubes and have gills, others have segmental, paired fleshy paddles
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leeches
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live in freshwater or moist terrestrial habitats, are either carnivorous or parasitic
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mollusks
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bilateral symmetry, coelomate, have mantle (extension of the body wall), open circulatory system (not confined to heart and blood vessels)
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3 most prominent classes of mollusks
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gastropods, bivalves, cephalopods
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gastropods
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have a muscular foot for locomotions, may possess a shell, feed using a radula (ribbon of tissue that bears numerous teeth),
use their skin and gills for respiration |
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bivalves
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line in fresh water and marine habitats, 2 shells that clamp, filter feed, burrow
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cephalopods
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marine, predatory carnivores, closed circulatory system, suction disks, expel water fro mantle cavity to move, high sensory system, capable of learning, may have ashell
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arthropods
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most abundant and diverse organisms on earth, bilateral symmetry, exoskeleton, open circulatory system
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arthropods are divided into 3 distinct regions
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head-feeding and sensing the environment
thorax- locomotion abdomen- digestion |
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Arthropods include:
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insects, arachnids, myriopods, crustaceans
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insects
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1 pair of antennae,
3 pairs of legs, 2 pairs of wings larva stage/metamorphasis use trachae for gsa exchange |
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completely metamorphasis
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egg, larva (feeding stage), pupa(non-feeding stage), adult
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incomplete metamorphasis
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egg, nymph (feeding stage that resembles adult), adut
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arachnids
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lack antennae,
8 walking legs, venom, use of book lungs and trachae, abs produce silk |
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myriapods
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1 pair of antennae,
simple light-detecting eyes, respire with trachae, centipedes: carnivorous, millipedes: feed on decaying vegetation |
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crustacean
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aquatic, 2 pairs of antennae,
respire with gills, cmpd eyes, crabs, crayfish, shrimp, barnacles, lobster |
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echinoderms
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larve- bilateral symmetry, adults show radial symmetry, marine
deuterostome development, coelomate,internal skeleton, endoskeleton, lacka circulatory sytem, closest to us, must repoduce sexualy |
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water-vascular system
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endoderms have it;
consists of the sieve plate, a circular central canal, several radial canals, and numerous tube feet functions in locomotion, respiration, and food capture |
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chordates
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notochord- stiff flexible rod extending in length of the body
dorsal, hollow nerve cord- expands anteriorly to form brain pharyngeal gil slits- may form respiratory organs or may appear as grooves post anal tail- extends past the anus |
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are humans chordates?
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adults exhibit nerve cord characteristic, embryos exhibit all 4
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vertebrate chordates
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backbone composed of cartilage, endoskeleton that can grow and repair itself, includes: jawless, cartilaginous, and bony fishes, amphibians, reptiles, birds and mammals
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jawless fishes
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jawless, eel-shaped body and smooth unscaled skin, include hagfishes and lampreys
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hagfish
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marine,feed on worms, slime defense,lack a true backbone, most closely related to vertebrates
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lampreys
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spinal cord protected by cartilaginous segments, fresh and salt water, parasites of larger fish
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cartilaginous fishes
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marine, cartilaginous skeleton, leathery skin resppire using gills, 2 chambered heart, will sink if stop swimming
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bony fishes
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found in nearly every water habitat, ray-finned fishes (most diverse and abundant group of vertebrates) and lobe-finned fishes (amphibians)
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amphibians
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3 chambered heart, respire through lungs and moist skin, reproduce sexually
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reptiles and birds
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sheled amniote egg, adapted for life on land, respire thru only lungs, internal fertilization, reptile tough skin protects body and resists water loss, 4 chamber heart
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birds
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feathers (providee lift and control as well as insulation), hollwo bones (reduce weight of skeleton), single ovary, shelled eggs (frees females from carrying offspring), high metabolic rate, 4 chamber heart
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mammals
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warm blooded, high metabolic rate, 4 chambered heart, most have hair to protect and insulate, sweat scent and sebaceuous glands, mammary glands, all can do trial and error learning with highly developed brain
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purpose of sweat
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evaporating water cools skin
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purpose of sebaceous gland
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oil keeps water in skin
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mammals can be divided into 3 groups
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monotremes, marsupials, placenta mammals
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monotremes
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lay leathery eggs, newly hatched young nourished by milk
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marsupials
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ebryos begin development in uterus, post birth development in protective pouch
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placenta mammals
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most mammals, most diverse, entire embryonic development in uterus which contains placenta
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purpose of placenta
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functions in gas, nutrient, and waste exchange b/w circulatory systems of mother and embryo
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