What defines animals?
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Terms in this set (51)

Structures for feeding
Sensing the environment
Processing information is concentrated

Cerebral ganglion/brain- large mass of neurons that is responsible for sending and receiving information to and from the body


Sensory organs- sight, hearing, taste, smell, touch
Some ability to sense temperature, magnets fields, electric fields, barometric pressure
What are the 3 most diverse lineages?Arthopods- 1.1 M Mollusks- 85,000 Chordates- 65,000What are the feeding strategies of animals? and what animals use eachSuspension/filter feeders- mostly aquatic Capture for by filtering out particles floating in water or drifting through air Deposit feeders- simple, worm-like feeding structures Ingest organic material that has been deposited within a substrate or on its surface Fluid feeders- specialized; few species Suck up or mop up liquids Mass feeders- most predators and herbivores Take chunks of food into their mouthsWhat are the 2 types of fertilization- costs/benefits What are the types of reproductionExternal- many young, little investment Internal- fewer young, more investment Vivparous- internal nourishment, live birth Oviparous- nourishment from external eggs Oviviparous- nourishment from internally retained eggs, live birthWhy is movement beneficial? What are the types of support?Find food Find mates Escape predators Disperse to new habitats Hydrostatic skeleton- support from flexible body wall in tension surrounding fluid or soft tissue under compression Exoskeleton- support from rigid structures on outside of body Endoskeleton- support from rigid structures inside the bodyWhat were the 3 major places related to the Cambrian and what are their relative times? What was found in eachMistaken Point- Canada- 565 MYA Lasted 20 M years, then went extinct Fractal sessile animals Oldest animal fossils Ediacaran Hills- Australia- 15 M years after Mistaken Point- 550 MYA mobile, soft bodied, bilateral evolution of head sexual reproduction Burgess Shale- Canadian Rockies- 505M MYA legs, eyes, armor/exoskeleton/shells move to land 428MYAHow might of Snowball Earth contributed to Cambrian diversity?Global glaciation Flush of nutrients into the ocean causing life in oceans to take offWhen the did the Cambrian Explosion start? What are the hypotheses for what triggered it?542 MYA 1. Higher oxygen levels- make aerobic respiration more efficient and increased respiration is required to support larger, more active animals. Oxygen levels may have reached a threshold at the start of the Cambrian Explosion 2. Evolution of predation- selection for shells, exoskeletons, rapid movement, sensory organs, and other defenses driving morphological divergence among prey 3. New niches beget more new niches- once animals could move off ocean floor, they could exploit algae and other resources The ability to exploit new niches created new niches for predators, driving speciation and divergence 4. New genes, new bodies Earliest animals had few or no HOX genes. Gene duplication and diversification increased the number of Hex genes in animals Made it possible for larger, more complex bodies to evolveWhat are HOX genes and how role do they play int he evolution of animalsdevelopmental regulatory genes controls the identity of body parts lays out the body plan "Eye goes here" Similar across animal groups Mutation in regulatory genes can shut off and turn on genesCharacteristics of platyhelminthes Coelom Digestive system Circulatory system Gas exchange Free-living or sessile Parasitic? Where do tapeworms come from? What do they do?Coelomates two way none diffusion some free living (planaria) Some parasitic (trematodes & tapeworms) Eating undercooked meat Attach to intestinal wall and absorb your food and you poop them outCharacteristics of AnnelidaSegmented Worms: Bristle worms, earthworms, leeches Repeated features: Chaetae- bristle-like extensions Parapodia- lobe like appendagesCharacteristics of mollusks Characteristics of chitons Characteristics of clams, mussels, scallops, oysters Characteristics of snails, slugs,, nudibranchsTrue coelomate Foot, visceral mass, mantle Radula- for feeding 8 shell plates, marine herbivore Bivalves- two valves/shells filter feeders, mostly sessile Moves with muscular foot, herbivorous or predatory, radula for feeding Active predators, foot modified to tentacles, mantle for jet propulsion, shell lost or reduced (except Nautilus), extremely intelligent, well-developed brains and nervous systemEcdysozoan characteristics Nematoda characteristicsEcdysis- molting Hard exoskeleton or cuticle One way digestive tract Unsegmented roundworms Pseudocoelomate Cuticle live in all habitats Mostly free living, some parasitic soil nematodes- up to 9 billion/acre 4/5 animal individuals are nematodesArthropoda characteristicsExoskeleton made of chitin with Calcium carbonate in many marine species Ecdysis Paired, jointed appendages, segments allow for wide range of specializations Segmented body plan- head (attend, mouthparts) Thorax- legs/wings, may be fused with head and form cephalothorax Abdomen- often specialized appendages and contains organs or is muscularWhy is the water to land transition important? Adaptations must allow for what?Open up entirely new habitats and new resources to exploit Gas exchange, avoid drying out, hold up their bodies under their own weightWater to land Transition: round worms and earthworms have ___ Some terrestrial anthropoids and mollusks have ___ Vertebrates survive being on land by ____ Insects evolved ____ Dessication-resistant eggs evolved repeatedly in populations that made the transition to life on land Insects eggs ____ Snail and slug eggs ____High surface area to volume ratio -> higher gas exchange efficiency Gills or respiratory structures inside the body- minimizes water loss Lungs, limbs, amniotic egg waxy layer to minimize water loss from body surface- if environment dries, openings to respiratory passages can be closed thick membrane that keeps in moisture Thick shell that retains waterWhat are the synapomorphies of echinoderms? Internal or external fertilization? All terrestrial, marine, both? What organisms are included?1. Pentaradial symmetry in adults 2. Endoskeleton of calcium carbonate 3. Water vascular system w/ tube feet External Marine Sea stars, Brittle stars, sea urchins, sand dollars, sea cucumbersWhat are the synapomorphies of chordates?1. Pharyngeal gill slits- openings in the throat 2. Dorsal hollow nerve cord- comprised of projects from neurons 3. Notochord- stiff and supportive but flexible rod 4. Muscular post-anal tailWhat are the 3 subphyla of Chordata?1. Cephalochordata- lancelets 2. Urochordata- tunicates, sea squirts 3. VertebrataCharacteristics of cephalochordata22 species, all marine small, fish like animals filter feed through gill slits Swim by contracting muscles around notochord- swimming motion of fishesCharacteristics of urochordata2000 species, all marine Larvae- use tail muscles and notochord to move some are sessile as adults filter feed through gill slits Notochord, DHNC, tail only in larvae or sexually mature forms of motile species Pharyngeal gill slits in bothWhat are the synapomorphies of vertebrates? What happen to the DHNC, PGS, and NCVertebrae- column of cartilaginous or bony structures- protects spinal cord Cranium- bony, cartilaginous, or fibrous case that encloses the brain- protects brain and sensory organs DHNC- elaborated into the spinal cord- bundle of nerve cells that run from brain to body's posterior Pharyngeal pouches in embryos develop into gills in aquatic species Notochord- develop in all vertebrate embryos but the vertebral column functions in body support and movement Organizes the body plan early in development by secreting proteins that induce somite formation Somites- segmented blocks of tissue that differentiate into vertebrae, ribs, skeletal muscleWhat are the most primitive vertebrates? CharacteristicsHagfish and lampreys Lack hinged jaws, have crania eel-like Cartilaginous skeletonSynapomorphies of sharks and raysCartilaginous endoskeleton Jaws with bony teethWhat characteristics evolved with the ray finned fish? What percent of species of vertebrates do they make up? What's the other majority?Lungs, endoskeleton 50 TetrapodsWhat are the two lineages in lobe finned fishes?coelacanth and lungfishesHow many times did the translation from water to land occur in vertebrates? What 3 major lineages did it give rise to?Once Amphibians Mammals ReptilesWhat were limbs evolved from? Characteristics of them What was the limbs from fins hypothesis? Do any other animal groups have limb bones in this arrangmenet? What is evidence for the hypothesis?Lungfish Shallow, oxygen-poor water Breath w/ lungs, supplementing O2 taken in by gills Each limb has a single bony element that articulates w/ 2 bones arranged side by side, next to a series of elements farthest from eh body No Several regulatory proteins involved in development of fish fins and upper parts of mammal limbs are homologous- proteins produced by different Hox genes are found at the same times during development and in the same locations in fins and limbsWhat organisms make up Amphibia? CharacteristicsFrogs. toads Salamanders snake-like caecilians Tadpole-larvae- aquatic, gills, tail Adults- terrestrial, predators, lungs Facilitate gas exchange via skin Reproduction requires waterAmniotic egg membranes What surrounds those? What does it do? What surrounds that? What's the purpose of the membranes? What are the advantages of the amniotic egg?1 Amnion- contains embryo 2. Yolk sac- Contains nutrients from mother 3. Allantois- Contains waste Chorion- allows gas exchange Albumen- cushions developing embryo and provides nutrients (Provides water and mechanical support) Provides mechanical support and increase surface area for gas exchange Support an protection, nutrition, membranes increase surface- area volume ratio- allows for larger egg, Prevents water loss Allows reproduction in non-aquatic habitatsWhat is the synapomorphy of reptiles? What are they made of? What are the 4 major lineages of this group Characteristics of ReptilesScales Keratin 1. Lizards and snakes 2. Turtles 3. Crocodiles and alligators 4. Birds Scales, land egg (shell), ectoderms except for some dinosaurs and birds 3 or 4 chambered heartWhat adaptations did reptiles have for life on land?Skin is watertight by a later of scales Breath air through well-developed lungs lay shelled, amniotic eggs Ectotherms- Bask in sunlight, seek shade, and other behaviors to keep body temp at appropriate levelWhat did birds descend from? What are feathers What do they doLineages of dinosaurs that had feathers- Outgrowths of the skin composed of keratin Provide insulation Display Furnish the lift and steering required for flightBird characteristicsReduced snout and enlarged brain and eyes Elongated "keel" on sternum for attachment of flight muscles Produce heat in their tissues Hollow bones strengthened by "struts"What are the 3 subphyla of mammals?1. Monotremes (platypus and echidna)- 5 species Milk secreted from glands on belly Lay egg Only in Australia/ New Guinea 2. Marsupials- 350 species Live birth (viviparity) True nipples Young born early; complete development in pouch 3.. Eutherians- 5000 species True placenta (vivparity) Complete embryological development in wombWhat is a placenta?Modified amniotic egg Embryo still surrounded by an amnion with amniotic fluid Yolk sac becomes the umbilical cord Chorion becomes the placenta Placenta transfers gases, food, wastesCharacteristics of mammalsFur Mammary glands- produce milk which nourishes developing young (Lactation) Only vertebrates with cheek muscles and lips which makes sucking possible Endotherms- maintain high body temperature by oxidizing large amounts of food and generating large amounts of heat Body covered with layers of hair or fur made of keratinPrimate characteristicsHands and feet that are efficient at grasping Flattened nails instead of claws on fingers and toes Relatively large brains Color vision Complex social behavior Extensive parental care of offspring Forward-facing eyesWhat is the synapomorphy of hominids Why did we develop such large brains? Where did Homo Sapiens originate? What other species have been found in other parts of the world? Which species moved out of africa?Bipedalism Spoken language and tool use- need increased capacity to reason and communicate Africa H. erectus,, H. neanderthalensis, H. floresiensis H. Sapiens and H. erectusHow did the moon form?Another planet, Theia, collided with Earth's surface creating a wave that traveled across the planet which caused dust and rock to be sent into space, forming a ring around Earth. Which eventually formed a ballWhat enabled the mammals to survive the mass extinction that killed the dinosaurs?The ones that lived underground were sheltered from fire and heat. They also ate a wider variety of food so they found food easierWhen did Homo erectus first walk on the African savanna?1.5 million years ago