bio test #3
Terms
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- what is an animal?
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-heterotrophs that obtains nutrients by ingestion
- multi cellular eukaryote
- most are diploid
- most have muscles for movement
- most have nerve cells to conduct impulses
- some new development genes for animals - earliest fossils?
- ~600 million years ago (cambrian period)
- during cambrian period 545 years ago, there was an explosion of evolution in a ten year period
- alskgj
- reasons for cambrian explosion of evolution?
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-change in atmosphere
-predator prey relationships
-genetic changes in HOX genes - sponges (porifera)
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- about 9,000 species
- radial symmetry
- suspension feeders - cnidarians
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- radial symmetry
- incomplete digestive system
- digestion
- circulation
- physical support and movement
- cnidocytes (stinging cells) - bilateral symmetry
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- anterior and posterior end
- dorsal and ventral surfaces
- head is prominent part of animal
-houses main sensory organs (eyes, brain, mouth)
-nervous system (head and sensory organs branching throughout body)
- active and travel headfirst through environment - flatworms
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-bilateral symmetry
-complete digestive tract
-subgroups:
-freeliving- planaria
-flukes- parasites- schistosoma
-tapeworms- parasitic- no digestive tract, absorb nutrients directly through body. each segment has male and female parts for reproduc. - body cavity
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-psuedocoleumn- not completely lined by tissues from the mesoderm
-coleumn- completely lined by tissues from the mesoderm- connect and suspend organs and digestive tract from body wall.
-advantages: hydroskeleton provides structure for muscles to exert force for movement. cushions organs. may circulate oxygen and nutrients and assist in waste disposal. - roundworms
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-cuticle
-complete digestive tract
- psuedocolumn
- most numerous in number of species and individuals.
- C.Elegans Trichinella Spiralis - mollusks
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-150,000 known species
- foot, visceral mass, mantle, radula
- true coleumn
- circulatory system - Gastropods (subgroup of Mollusk)
- -lack a mantle
- bivalves
- -shelves divided into two halves
- cephalopods
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-built for speed and agility
- no shell, internal shell or, small shell - segmented body
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-subdivision of body along length into series of repeated parts
-allows great flexibility and mobility - annelids
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-segmented body
-about 15,000 species
-examples: earthworms, leaches, polychaetes - arthropods
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-means jointed appendages
-about 1 million species
-about 10^18 individuals
-exoskeleton -hard external skeleton: made up of protein and chitin, for protection, also points of attachment for muscles.
-requires molting for changing of exoskeleton
-distinct segments- head, thorax, abdomen (head and thorax may combine to make a cephathorax) - echinoderms
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-sea stars, sand dollars, and sea urchins
-all marine
-no segments
-most radial symmetrical (have bilateral larvae stage that differentiates them from cnidarians)
-spiny
-endoskeleton
-water vascular system
-can regenerate lost limbs - chordata
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-four distiguishing features- dorsal hollow nerve chord, notochord, pharengial slits, post anal tail.
-invertebrate chordates- tunicates, lancelets
- vertebrates
-skull and backbone
-most have hinged jaws (except agnatians) - chondrichthyes
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-cartilagenous fishes
-sharks, rays and skates
-flexible skeletons
-most are predators
-lateral line system (nerves running along side of body that sense pressure changes in water) - osteichthyes
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-bony fishes
-lateral line system
-keen sense of smell
-excellent eyesight
-operculum (protective flap that covers gills)
-swim bladder- keeps bouyant
-most are ray finned fishes
-lobe finned fish- coelacanth
-lungfishes- inhabit stagnant waters, gulp air into lungs connected to pharnyx - amphibians
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-mixture of aquatic and terrestrial life
-adults can live on land, but eggs would dry out
-about 4,800 species
-first terrestrial vertebrates
-transition from fish about 400MYA
-dominated in Carboniferous forests - reptiles
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-about 6500 species
-lizards, snakes, turtles, crocidiles
-scaly skin (keratin waterproofs)
-amniotic eggs (nourished by yolk)
-ectothermic
-dinosaurs- dominated 200MYA, fade 70MYA, mass extinct 65MYA - birds
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-8600 species
-adaptations for flight:
-no teeth
-tail supported by a few vertebrate
-hollow feathers
-bones have honeycomb structure for light strength
-flight feathers shape wings into airfoil
-large breast muscles tied to a keel like breastbone
-high metabolism
-efficient circulatory system
-best vision of all vertebrates
-relatively large brains - mammals
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-evolved from reptiles 220MYA
-became more diverse after dinosaurs
-most terrestrial
-1,000 species fly, 80 swim.
-endothermic
-hair, mammary glands - monotreme(division of mammal)
- -egg laying mammals (duck billed platypus)
- marsupials (division of mammals)
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-brief gestation
-born tiny
-complete development attached to mother's nipple.
-developing young usually protected in external pouch.
- nearly all in C. S. America, New Zealand and Australia - eutherians
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-95% of 4500 species of mammals
-strong connection between mother and young through placenta - earliest primates?
- 65MYA
- 2 groups of primates
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-prosimians-lemurs and loris
-anthropoids (humans and monkeys)
-may have evolved from prosimians 45 MYA - old world monkeys
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-some arboreal and some ground dwelling
-nostrils close together, some with hard seat pad. - new world monkeys
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-all arboreal
-nostrils wide open and farther apart
-many with prehensile tail - humans probably diverged with chimpanzees 5-7MYA
- lk
- apes
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-closest relatives of humans
-no tail
-forelimbs longer than hindlimbs
-chiefly vegetarians (chimpanzees eat insects and small vertebrates)
-larger brains relative to monkeys
-biochemical evidence that chimpanzee and gorilla more closely related to humans than other apes
-human DNA differs from chimpanzee DNA by only 3% - gibbons
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-only entirely arboreal apes
-only apes that are monogamous - orangutan
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-shy solitary species from Borneo and Sumatra
-largest living arboreal mammal - gorilla
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-largest of all primate species
-walk on knuckles - chimpanzee and bonobos
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-knuckle walkers
-make and use simple tools
-raid other groups of their same species - humans 5major differences
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-increased brain size (3X larger than ancestors 6MYA)
-shorter jaws, flatter faces
-bipedal posture
-reduced size between sexes
-key changes in family structure - upright posture origins
- hominids in forests which may have made entering the savannah easier.
- enlargement of human brain?
- 2.5MYA
- homo habilus
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-existed for about a million years with Australopithecines
-found simple tools useful
-scavenging, gathering and hunting
-may have given rise to homo erectus - homo erectus
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-(1.8MYA-500,000YA)
-taller than habilus and larger brain
-males about 1.2x size of females
-may have been start of monogamy
-first to spread out of africa to asia and europe about 1.8 MYA
-lived in huts, wore clothes from skins
-gave rise to homo sapiens - neanderthals
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-europe (200,000 to 40,000 years ago)
-short and stocky, heavily muscled
-skilled tool makers
-participated in rituals that required abstract thought - homo sapiens origins
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-may have originated 100,000 years ago
-second wave of H.Erectus led to H.Sapiens - highlights of h. sapiens evolution
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-evolution of erect stance (remodeling of foot, pelvis and vertebral column)
-enlargement of brain
-prolonged prenatal care - 1st major stage of cultural evolution
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-scavenging main way of accessing food
-hunting not feasible until 50,000 years ago with invent of tools
-may have caused extinction of large numbers of predators and prey
-started divisions of labor and semi permanent living establishments - 2nd major stage of cultural evolution
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-10,000-15,000 years ago
-more intensive agricuture, populations grew
-permanent settlements and first cities arose
-specialization of labor - 3rd major stage of cultural evolution
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-industrial revolution in Europe in 18th centur
-mediciines reduced death rate
-fewer needed for farming, moved to cities - digestion
- -food and drink are swallowed- swallowing causes reflex that closes the trachea and opens the esophagus- food moves down with peristalsis- stomach secretes gastric juices that start digestion-partially digested food moves into small intestine- what passes through small intestine goes into colon and rectum- what was absorbed by stomach and s. intest moves into liver
- gastric juice components
- mucus, enzymes and strong acids.
- small intestine
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-6.5 meters long, but only 2.5cm in diameter
-most nutrients are absorbed in small intestine
-large surface area due to many folds (villi) and projects at the tip of epipethelial cells (microvilli)
-blood from small intestine goes into liver - liver
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-stores glucose as glycogen and maintains glucose/blood concentration
-detoxifies toxins - ethanol digestion
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-some ethanol can be absorbed through stomach lining (ethanol is bipolar)
-in stomach are enzymes that break down alcohol
-blood from stomach goes to liver
-ethanol that dissolves into the epithelial cells is also broken down by detoxifying enzymes.
-ethanol that wasn't broken down in epethilial cells and stomach is broken down here - what affects BAC?
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-amount of alcohol
-activity of enzymes in epethelial layer and liver
-food consumed
-gender (women have less body water and lower activity of ADH) - effects of alcohol consumption?
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-fat and protein accumulation in liver leading to hepatocytes that can lead to necrosis and fibrosis
-enhanced chance of cancer
-reduceds quality of sleep
-memory impairment
-brain shrinkage
-alters reproductive hormones
-lower calcium levels - muscle contraction and movement
- signal from brain passes down spinal cord to nuerons with axons that pass out of the spinal cord that attach to muscle fibers (nueromuscular junctions)-triggers release of NT (acetylcoline)
- trigger salivation
- chemicals in the air are taken in through the nose and mixed with mucus in the back of the nose- chemicals bind to cilia that penetrate mucus layer- changes pattern of nerve impulses which the brain interprets as a smell
- salivation
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-salivary glands secrete saliva at the sight or smell of food (1L/day)
-slippery glycoprotein that protects inside of mouth
-buffered to nuetralize food acids
-antibacterial agents that kill bacteria
-contains digestive enzymes - taste buds
- -group of sensory cells with proteins in their membranes that interact with chemicals in foods.
- cones
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-stimulated by bright light and distinguish color
-6 million in retina - rods
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-extremely sensitive to light and enable us to see in dim light
-about 125 million in retina
-found primarily in retina, completely absent from fovea - rhodopsin
- rods
- photopsins
- cones
- color blindness
- -due to a defeciency in cones
- neurotransmitters
- -generally small nitrogen containing molecules