Transcript Unit Test Review

Animal Kingdom Evolution
5 Defining characteristics of the animal kingdom:
1) Heterotrophic eukaryotes; ingestion
2) Lack cell walls; collagen
3) Nervous & muscular tissue
4) Sexual; diploid; cleavage; blastula; gastrulation; larvae;
metamorphosis
5) Regulatory genes: Hox genes
Animal phylogeny
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*Monophyletic; colonial flagellated
protist ancestor
First split
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1- Parazoa vs. Eumetazoa dichotomy:
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*(Parazoa)~ no true tissues example
sponges
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*(Eumetazoa)~ true tissues
all other animals
Parazoa
*Parazoa: No true tissues
• Invertebrates
• No true tissues, unspecialized
cells:
*Sponges Closest lineage to protists
• Phylum Porifera
Phylum: Porifera (“pore bearer”)
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*Sessile (attached to bottom)
Spongocoel (central cavity)
*Osculum (large opening)
Choanocytes (flagellated collar cells)
*Hermaphroditic (produce both sperm and eggs)
• Eumetazoa:
True Tissues: Everything but
sponges
• 2nd split – Body Symmetry
• Radiata vs.Bilateria dichotomy:
1) *radial body symmetry
*Cnidaria (hydra; ‘jellyfish’; sea anemones) &
*Ctenophora (comb jellies)
2) *bilateral body symmetry (also: **cephalization)
• all other animals
Eumetazoa
The Radiata, Diploblastic
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Radial symmetry
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Phy: Cnidaria (hydra, jellies, sea anemones,
corals)
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*No mesoderm; gastrovascular cavity
(GVC)(sac with a central digestive cavity)
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Hydrostatic skeleton (fluid held under
pressure)
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Polyps and medusa
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Cnidocytes (cells used for defense and prey
capture)
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Nematocysts (stinging capsule)
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Phy: Ctenophora (comb jellies)
3. Gasturlation: diploblastic vs.
triploblastic
• 3- Gastrulation: germ layer
development; ectoderm (outer),
mesoderm (middle), endoderm (inner)
• diploblastic-2 layers; no mesoderm;
– Radiata
– Phy: Cnidaria (hydra, jellies, sea
anemones, corals)
• triploblastic-all 3 layers
– *bilateria symmetry
– All others
4- Acoelomate, Pseudocoelomate, and Coelomate
• All are triploblastic animals
• *acoelomates solid body, no body
cavity
– (Platyhelminthes-flatworms)
– mesoderm but, GVC with only one
opening
– *Some cephalization
• *pseudocoelomates body cavity,
but not lined with mesoderm called
– (Rotifers); *1st with a complete
digestive track
– Parthenogenesis: type of reproduction
in which females produce offspring
from unfertilized eggs
• Coelomate: true coelom (body
cavity) lined with mesoderm called
– Phy: Nematoda (roundworms)
– Complete digestive track; no circulatory
system
Animal phylogeny
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• *Protostomes
• Phylogenetics debated….
1)Phy: Nemertea (proboscis and
ribbon worms)
• *Complete digestion and
closed circulatory system
(blood)
2) Phy: the lophophorates (sea
mats, tube worms, lamp
shells)
The Coelomates: Protostomes, II
3) Phy: Mollusca (snails, slugs,
squid, octopus, clams, oysters,
chiton)
• Soft body protected by a hard
shell of calcium carbonate
• Foot (movement), visceral
mass (internal organs); mantle
(secretes shell); radula (rasplike scraping organ)
• Ciliated trochophore larvae
(related to Annelida?)
The Coelomates: Protostomes, III
4) Phy: Annelida (earthworms,
leeches, marine worms)
• True body segmentation
(specialization of body
regions)
• Closed circulatory system
• Metanephridia: excretory
tubes
• “Brainlike” cerebral ganglia
• *Hermaphrodites, but
cross- fertilize
QuickTime™ and a
Cinepak decompressor
are needed to see this picture.
The Coelomates: Protostomes, IV
5) Phy: Arthropoda
trilobites
(extinct); crustaceans (crabs,
lobsters, shrimps); spiders,
scorpions, ticks (arachnids);
insects (entomology)
• *2 out of every 3 organisms
(most successful of all phyla)
• *Segmentation,
• *hard exoskeleton (cuticle)~
molting,
• *jointed appendages; open
circulatory system
(hemolymph);
• *extensive cephalization
Insect characteristics
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Outnumber all other forms of life
combined
Malpighian tubules: outpocketings
of the digestive tract (excretion)
Tracheal system: branched tubes
that infiltrate the body (gas
exchange)
*Metamorphosis…...
*•incomplete: young resemble
adults, then molt into adulthood
(grasshoppers)
*•complete: larval stages (looks
different than adult); larva to adult
through pupal stage
QuickTime™ and a
Cinepak decompressor
are needed to see this picture.
The Coelomates: *Deuterostomes, I
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1) Phy: Echinodermata (sea stars,
sea urchins, sand dollars, sea lilies,
sea cucumbers, sea daisies)
Spiny skin; sessile or slow moving
Often pentaradial
Water vascular system by hydraulic
canals (tube feet)
QuickTime™ and a
Cinepak decompressor
are needed to see this picture.
Deuterostomes
• Next branch
• Chordates
• *Notochord: longitudinal, flexible
rod located between the
digestive and the nerve cord
• *Dorsal, hollow nerve cord;
eventually develops into the
brain and spinal cord
• *Pharyngeal slits; become
modified for gas exchange, jaw
support, and/or hearing
• *Muscular, postanal tail
Invertebrate chordates
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Both suspension feeders…..
Subphy: Urochordata (tunicates; sea squirt); mostly sessile & marine
Subphy: Cephalochordata (lancelets); marine, sand dwellers
*Importance: vertebrates closest relatives; in the fossil record,
appear 50 million years before first vertebrate
• *Paedogenesis: development of sexual maturity in a larva (link with
vertebrates?)
Subphylum: Vertebrata
• Retain chordate characteristics with
specializations….
• *Neural crest: group of embryonic
cells near dorsal margins of closing
neural tube
• *Pronounced cephalization:
concentration of sensory and
neural equipment in the head
• *Cranium and vertebral column
• *Closed circulatory system with a
ventral chambered heart
Vertebrate diversity
• Phy: Chordata
• Subphy: Vertebrata
– Superclass: Agnatha
jawless vertebrates
(hagfish, lampreys)
– *Most primitive, living vertebrates
Vocabulary
tetrapods (‘4-footed’)
amniotes (shelled egg)
Superclass Gnathostomata, I
• Placoderms (extinct): first with hinged jaws and paired appendages
• Class: Chondrichthyes~ *Sharks, skates, rays
• *Cartilaginous fishes; well developed jaws and paired fins; continual water
flow over gills (gas exchange); lateral line system (water pressure changes)
• *Life cycles:
• *Oviparous- eggs hatch outside mother’s body
• *Ovoviviparous- retain fertilized eggs; nourished by egg yolk; young born
live
• *Viviparous- young develop within uterus; nourished by placenta
Superclass Gnathostomata, III
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Class: Amphibia
*1st tetrapods on land
Frogs, toads, salamanders, caecilians
Metamorphosis; lack shelled egg;
moist skin for gas exchange
Superclass Gnathostomata, IV
• Class: Reptilia
• Lizards, snakes, turtles, and crocodilians
• *Amniote (shelled) egg with extraembryonic membranes (gas
exchange, waste storage, nutrient transfer);
• absence of feathers, hair, and mammary glands;
*ectothermic; scales with protein keratin (waterproof); lungs;
ectothermic (dinosaurs endothermic?)
Superclass Gnathostomata, V
• Class: Aves
• Birds
• *Flight adaptations: wings
(honeycombed bone); feathers
(keratin); toothless; one ovary
• *Evolved from reptiles (amniote
egg and leg scales);
endothermic *(4-chambered
heart)
•Archaeopteryx (stemmed from an ancestor that
gave rise to birds)
Superclass Gnathostomata, VI
• Class: Mammalia
• *Mammary glands; hair (keratin);
endothermic; 4-chambered heart;
large brains; teeth differentiation
• *Evolved from reptilian stock
before birds
• *Monotremes (egg-laying):
platypus; echidna
• *Marsupials (pouch): opossums,
kangaroos, koalas
• *Eutherian (placenta): all other
mammals
Order: Primates (evolution)
• *Characteristics: hands & feet for grasping;
large brains, short jaws, flat face; parental
care and complex social behaviors
• Suborder: Prosimii •lemurs, tarsiers
• Suborder: Anthropoidea •monkeys, apes,
humans (opposable thumb)
• *45-50 million years ago
• *Paleoanthropology: study of human origins
• *Hominoid: great apes & humans
• Hominid (narrower classification):
√ australopithecines (all extinct)
*√ genus Homo (only 1 exant, sapiens)
Human evolution
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Misconceptions:
1- Chimp ancestor (2 divergent branches)
2- Step-wise series (coexistence of human species)
3- Trait unison(all traits at once) vs. mosaic
evolution(over time) (*bipedalism, upright, enlarged
brain)
The first humans
• Ape-human split (5-7 mya)
• Australopithecus; “Lucy” (4.0 mya)
• Homo habilis; “Handy Man” (2.5
mya)
• Homo erectus; first to migrate (1.8
mya)
• Neanderthals (200,000 ya)
• Homo sapiens (100,000 ya?)
• Multiregional model
(parallel evolution)
• “Out of Africa”
(replacement evolution)
Tissues: groups of cells with a common
structure and function (4 types)
• Anatomy: structure
• Physiology: function
• Type 1- Epithelial: outside of body
and lines organs and cavities; held
together by tight junctions
• basement membrane: dense mat of
extracellular matrix
• Simple: single layer of cells
• Stratified: multiple tiers of cells
• Cuboidal (like dice)
• Columnar (like bricks on end)
• Squamous (like floor tiles)
• Glandular (can secrete) mucous
membrane
Connective Tissue (6 kinds)
• Type 2- Connective Tissue: bind and support other
tissues; scattered cells through matrix
3 kinds of fibers:
– A-Collagenous fibers (collagen protein) non elastic B-Elastic
fibers (elastin protein) C-Reticular fibers (thin branched
collagen fibers)
• Loose connective tissue: binds epithelia to underlying
tissue; holds organs (has all 3 fiber types)
– Two types of cells dominate
• 1-Fibroblasts- secretes the protein for extracellular fibers
• 2-Macrophages- amoeboid WBC’s; phagocytosis
• Adipose tissue (specialized form)- fat storage; insulation
Connective Tissue, Type II
• Fibrous connective tissue: parallel
bundles of cells
– 1-Tendons- muscles to bones
– 2-Ligaments- bones to bones; joints
(BOBOLI)
• Cartilage: collagen in a rubbery matrix
(chondroitin); flexible support
• Bone: mineralized tissue by osteoblast
cells
• Blood: liquid plasma matrix; erythrocytes
(RBC’s) carry O2; leukocytes (WBC’s)
immunity
Nervous Tissue, Type III
• 3-Nervous: senses stimuli and
transmits signals from 1 part of
the animal to another
• *Neuron: functional unit that
transmits impulses
• *Cell body (contains nucleus)
• *Dendrites: transmit impulses
from tips to rest of neuron
• *Axons: transmit impulses
toward another neuron or
effector
Muscle Tissue (3 kinds)
• 4- Muscle: capable of
contracting when stimulated
by nerve impulses;
myofibrils composed of
proteins actin and myosin; 3
types:
• A- Skeletal: voluntary
movement (striated)
• B- Cardiac: contractile wall
of heart (branched striated)
• C- Smooth: involuntary
activities (no striations)
Internal regulation
• Interstitial fluid: internal fluid
environment of vertebrates;
exchanges nutrients and wastes
• *Homeostasis: “steady state” or
internal balance
• *Negative feedback: change in a
physiological variable that is being
monitored triggers a response that
counteracts the initial fluctuation;
i.e., body temperature
• *Positive feedback: physiological
control mechanism in which a
change in some variable triggers
mechanisms that amplify the
change; i.e., uterine contractions
at childbirth
Metabolism: sum of all energyrequiring biochemical reactions
• *Catabolic processes of
cellular respiration
• Calorie; kilocalorie/C
• *Endotherms: bodies
warmed by metabolic heat
• *Ectotherms: bodies
warmed by environment
• Basal Metabolic Rate
(BMR): minimal rate
powering basic functions of
life (endotherms)
• Standard Metabolic Rate
(SMR): minimal rate
powering basic functions of
life (ectotherms)
Chapter 48 ~ Nervous System
http://outreach.mcb.harvard.edu/animations/synaptic.swf
The Nervous System
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Neurons
Glial cells
Axon
Dendrite
Synapse
Neurotransmitters
Action potential
• Motor neurons
• Interneurons
• Sensory neurons
• Myelin sheath
• Schwann cells
• Reflex arc
Nervous systems
• Effector cells~ muscle or
gland cells
• Nerves~ bundles of neurons
wrapped in connective tissue
• Central nervous
system (CNS)~ brain and
spinal cord
• Peripheral nervous
system (PNS)~ sensory
and motor neurons
Structural Unit of Nervous System
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Neuron~ structural and functional unit
Cell body~ nucelus and organelles
Dendrites~ impulses from tips to neuron
Axons~ impulses toward tips
Myelin sheath~ supporting, insulating layer
Schwann cells~ PNS support cells
Synaptic terminals~ neurotransmitter releaser
Synapse~ neuron junction
Simple Nerve Circuit
http://msjensen.cehd.umn.edu/1135/Links/Animations/Flash/0016-swf_reflex_arc.swf
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Sensory neuron: convey information to
spinal cord
Interneurons: information integration
Motor neurons: convey signals to
effector cell (muscle or gland)
Reflex: simple response; sensory to
motor neurons
Ganglion (ganglia): cluster of nerve cell
bodies in the PNS
Supporting cells/glia: nonconductiong
cell that provides support, insulation,
and protection
Neural signaling
http://bcs.whfreeman.com/thelifewire/content/chp44/4403s.swf
http://outreach.mcb.harvard.edu/animations/actionpotential.swf
• Membrane potential (voltage differences across the plasma
membrane)
• *Intracellular/extracellular ionic concentration difference
• K+ diffuses out (Na+ in); large anions cannot
follow….selective permeability of the plasma membrane
• Net negative charge of about -70mV
http://bcs.whfreeman.com/thelifewire/content/chp44/4402s.swf
Neural signaling
http://www.mind.ilstu.edu/curriculum/neurons_intro/flash_electrical.php?modGUI=232&compGUI=1827&itemGUI=3158
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Excitable cells~ cells that can change membrane potentials (neurons, muscle)
Resting potential~ the unexcited state of excitable cells
Gated ion channels (open/close response to stimuli): photoreceptors; vibrations in air
(sound receptors); chemical (neurotransmitters) & voltage (membrane potential
changes)
Graded Potentials (depend on strength of stimulus):
1- Hyperpolarization (outflow of K+); increase in electrical gradient; cell becomes more
negative
2- Depolarization (inflow of Na+); reduction in electrical gradient; cell becomes less
negative
Neural signaling
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Threshold potential: if stimulus reaches a
certain voltage (-50 to -55 mV)….
The action potential is triggered….
Voltage-gated ion channels (Na+; K+)
1-Resting state •both channels closed
2-Threshold •a stimulus opens some Na+
channels
3-Depolarization •action potential
generated •Na+ channels open; cell
becomes positive (K+ channels closed)
4-Repolarization •Na+ channels close,
K+ channels open; K+ leaves •cell
becomes negative
5-Undershoot •both gates close, but K+
channel is slow; resting state restored
Refractory period~ insensitive to
depolarization due to closing of Na+
gates
Neural signaling
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“Travel” of the action potential is self-propagating
Regeneration of “new” action potentials only after refractory period
Forward direction only
Action potential speed:
1-Axon diameter (larger = faster; 100m/sec)
2-Nodes of Ranvier (concentration of ion channels); saltatory conduction;
150m/sec
Synaptic communication
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Presynaptic cell: transmitting cell
Postsynaptic cell: receiving cell
Synaptic cleft: separation gap
Synaptic vesicles: neurotransmitter
releasers
Ca+ influx: caused by action
potential; vesicles fuse with
presynaptic membrane and
release….
Neurotransmitter
http://www.bayareapainmedical.com/neurtrns.html
Neurotransmitters
http://www.blackwellpublishing.com/matthews/neurotrans.html
• Acetylcholine (most common)
•skeletal muscle
• Biogenic amines (derived from amino acids)
•norepinephrine
•dopamine
•serotonin
• Amino acids
• Neuropeptides (short chains of amino acids)
•endorphin
Nervous System (know this slide)
• Central Nervous System
– Crainial Nerves
– Spinal Nerves
• Peripheral Nervous System
– Sensory (afferent) Division
• Sensing external environment
• Sensing internal environment
– Motor (Efferent) Division
• Autonomic Nervous System
– Sympathetic Nervous System
» increase energy consumption
– Parasympathetic Nervous System
» conservation of energy
• Somatic Nervous System
– voluntary, conscious control, muscles
Vertebrate PNS
Vertebrate Skeletal Muscle
• *Contract/relax:
antagonistic pairs w/skeleton
• *Muscles: bundle of….
– Muscle fibers: single cell w/
many nuclei consisting of….
• *Myofibrils: longitudinal bundles
composed of….
– *Myofilaments:
» Thin~ 2 strands of actin
protein and one strand of a
regulatory protein
» Thick~ staggerd arrays of
myosin protein
http://entochem.tamu.edu/MuscleStrucContractswf/index.html
Vertebrate Skeletal Muscle
• Sarcomere: repeating unit of muscle
tissue, composed of….
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Z lines~sarcomere border
I band~only actin protein
A band~actin & myosin protein overlap
H zone~central sarcomere; only myosin
http://www.sumanasinc.com/webcontent/animations/content/muscle.html
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**Sliding-filament model
Theory of muscle contraction
Sarcomere length reduced
Z line length becomes shorter
Actin and myosin slide past each other (overlap
increases)
http://www.blackwellpublishing.com/matthews/myosin.html
**Actin-myosin interaction
• 1- Myosin head hydrolyzes ATP to ADP and inorganic
phosphate (Pi); termed the “high energy configuration”
• 2- Myosin head binds to actin; termed a “cross bridge”
• 3- Releasing ADP and (Pi), myosin relaxes sliding actin;
“low energy configuration”
• 4- Binding of new ATP releases myosin head
• Creatine phosphate~ supplier of phosphate to ADP
**Muscle contraction regulation
• Relaxation: tropomyosin
blocks myosin binding sites on
actin
• Contraction: calcium binds to
toponin complex; tropomyosin
changes shape, exposing
myosin binding sites
http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter10/animation__action_potentials_and_muscle_contraction.html
**Muscle contraction regulation
• Calcium (Ca+)~
concentration regulated by
the….
• Sarcoplasmic reticulum~
a specialized endoplasmic
reticulum
• Stimulated by action
potential in a motor neuron
• T (transverse) tubules~
travel channels in plasma
membrane for action potential
• Ca+ then binds to troponin
The Vertebrate Brain (know this slide)
• Forebrain
– •*cerebrum~ memory, learning, emotion
– •*cerebral cortex~ sensory and motor
nerve cell bodies
– •*corpus callosum~ connects left
(analytical) and right (creative)
hemispheres
– •*thalamus (main input/output from
cerebrum); *hypothalamus (hormone
production)
– Midbrain
– •inferior (auditory) and superior (visual)
colliculi
• Hindbrain
•*cerebellum~coordination of movement
•*medulla oblongata/ pons~
autonomic, homeostatic functions
Emotion
Cerebrum
Know that there are different lobes for different purposes. You
do not need to memorize this information.
• Cerebral
hemispheres
• Cerebral cortex—
”gray matter”
• Convolutions
• Cerebral lobes
• Frontal lobe—
conscious thought
and muscle control.
• Parietal Lobes—
receive information
from skin receptors.
• Occipital Lobe—
receives visual input.
• Temporal Lobe—has
areas for hearing and
smelling.
Pituitary Gland
Corpus Callosum