Life 103-Exam 3 Study Guide
Life 103-Exam 3 Study Guide Life 103
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This 20 page Study Guide was uploaded by Addy Carroll on Sunday April 10, 2016. The Study Guide belongs to Life 103 at Colorado State University taught by Dr. Dale Lockwood and Dr. Tanya Dewey in Winter 2016. Since its upload, it has received 25 views. For similar materials see Biology of organisms-animals and plants in Biology at Colorado State University.
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Date Created: 04/10/16
Life 103 Exam 3 Study Guide Light • Light and Plants -Light cues many key events in plant growth and development -Effects of light on plant morphology are called photomorphogenesis -Plants detect light direction, intensity, and wavelength -Action spectrum depicts relative response of a process to different wavelengths • Classes of Light Receptors -Blue-light photoreceptors ~Control hypocotyl elongation ~Control stomatal opening ~Control phototropism -Phytochromes ~Pigments that regulate many of a plant’s response to light throughout its life ~Seed germination ~Shade avoidance Animal Diversity and Evolution • Themes of Biology -Organization-structure and function, emergent properties, reductionism -Information-information is transferred between generations through genes (heredity) -Energy and Matter-all organisms require energy and matter, resources are often limited, look for trade-offs -Interactions-interactions are important at all levels of organization (cell to organisms to communities to the biosphere) -Evolution-nothing in biology makes sense except in the light of evolution • Themes in Animal Diversity -Trends in evolution -Tradeoffs and constraints -Different perspectives and ways of life • What is science? -Asking testable questions, formulated as hypotheses -Using evidence to answer those questions -Employing parsimony-simple explanations are preferred -Biology is a science -Science is a way of approaching problems that is applicable to nearly every aspect of your life • Eukaryan Diversity -Protists -Plants -Fungi -Animals • What are animals? -Metazoans -zoo or zoa=animals ~Ex.) Zoology • How well do we know animals? -<1million named species -Estimates up to 7.8 million total -86% of species on land yet to be discovered -91% of marine species yet to be discovered -Even in very common places, there are still many more species to be discovered -Most species on this planet are animals -70% of animals are insects -Animals have been around for a long time, but relative to every other species, they’re relatively recent • Ediacaran Origin -Animals evolved, including extant taxa and extinct forms -Only a few animal phyla evolved • Cambrian Explosion -Oldest fossils of half of extant animal phyla -Most major animal body plans evolve -Almost every other animal phyla that didn’t evolve in Ediacaran evolved in Cambrian • What are animals? =Metazoans -Multicellular -Ingestive heterotrophs ~Do not produce own food; take food into body and digest internally -Move under own volition at some point in life ~At some point they were motile -Lack cell walls, have structural proteins (extracellular matrix) -Unique, specialized cells: nerve and muscle (except sponges) ~Most animals have these cells, whereas they aren’t found in any other species -Sexual reproduction -2n (diploid) dominant -Flagellated sperm, non-motile egg -Most have larval stage -Cells are organized into tissues -Conserved genes control development (Hox genes) -Zygote undergoes cleavage, forms blastula, gastrulation • Eumetazoa=true tissues -Doesn’t include sponges because they don’t have true tissues -Metazoa includes sponges, but eumetazoa doesn’t • Themes in animal evolution (see textbook figure 32.11) -Origin of multicellularity -Origin of bilateral symmetry, cephalization, and the nervous system -Origin of embryonic tissue layers -Origin of a coelom -Origin of protostome and deuterostome development -Origin of segmentation • Origin of multicellularity -Choanoflagellates are the unicellular sister group to animals (see textbook figure 32.3) -Evolved at the origin of animals (Metazoa; includes sponges and all other animals) • Origin of bilateral symmetry, cephalization (formation of a head), and the nervous system -Types of symmetry ~Bilateral symmetry (Ex. Beetle) ~Radial symmetry (Ex. Coral polyp) ~No symmetry (Ex. Sponge) ~Pentaradial symmetry/pentamerism (echinoderms, except their larvae have bilateral symmetry) -Bilateral symmetry means you can have a head = cephalization ~Having a head gives the animal directionality (front and a back) ~Having a head gives the animal the ability to eat/be a predator -Concentrate sensory apparatus and nervous system at head -Evolved at the Bilateria origin (has bilateral symmetry if ancestor is Bilateria, Ctenophora and Cnidaria have radial symmetry, and sponges have no symmetry) -Genetic mechanisms responsible for bilateral symmetry and cephalization are shared (homologous) • Origin of embryonic tissue layers -Diploblastic=2 tissue layers (Endoderm and Ectoderm) -Triploblastic=3 tissue layers (Endoderm, Mesoderm, and Ectoderm) -Species with Bilateria ancestor are triploblastic, while Ctenophora and Cnidaria are diploblastic • Origin of a coelom -Animals are tubular-tubes within tubes -Coelom- a fluid-filled body cavity between the inner and outer tubes; disengages gut from outer layers, space for nutrients to move, forms basis of hydrostatic skeleton -3 body plans (see textbook figure 32.9) ~Acoelomate=no coelom ~Coelomate=has coelom ~Pseudocoelomate=false coelom (not a true coelom) -Pseudocoelomate has the space touching both the mesoderm and endoderm, while a true coelom only touches the mesoderm -Cannot say the coelomate evolved at a specific point of the tree because the body plans are randomly distributed ~Diploblastic and sponges don’t have coeloms ~Body plans scattered among Bilateria species • Origin of protostome and deuterostome development -“Stoma”=opening or mouth -Protostome-the mouth is formed before the anus ~”First mouth” -Deuterostome-the anus is formed before the mouth ~”Second mouth -The first opening in protostomes is the mouth, while the first opening in deuterostomes is the anus -Deuterostomes evolved at Deuterostomia -Protosomes, or “Spiralia,” evolved at Lophotrochozoa and Ecdysozoa • Origin of segmentation -Not all animal groups show segmentation -Common genes called Hox genes control segmentation -Suggesting flexible response through evolutionary history -Why segmentation? ~Permits specialization-genetic duplication releases copies to be modified for new purposes-look for this theme in vertebrate evolution Animal Taxa: Invertebrates I (Diversity) • Invertebrate Diversity (see textbook figure 33.3) -Morphological and molecular data are combined to understand relationships among animal phyla -Molecular (DNA) data has revolutionized our understanding • “Big 9” animal phyla -Porifera -Cnidaria -Platyhelminthes -Mollusca -Annelida -Nematoda -Arthropoda -Echinodermata -Chordata • *Porifera (sponges) -5,000-10,000 species -Filter feeding -No symmetry -Sessile -Mostly marine • Ctenophora (comb jellies) -100-150 species -Predatory -Radially symmetrical -Motile (via cilia) -Entirely marine • *Cnidaria (jellyfish, corals, anemones) -Over 10,000 species -Predatory or filter feeding -Radially symmetrical -Both motile and sessile -Mostly marine • Placozoa (“flat animals”) -1 to a few species -Detritivore -Radially symmetrical -Motile (via flagella) -Entirely marine • Acoela (acoel flatworms) -Approximately 400 species -Predatory -Bilaterally symmetrical -Motile (via cilia) -Mostly marine • Rotifera (wheel animals) -Filter feeding -Bilaterally symmetrical -Motile -Mostly freshwater • Acanthocephala (spiny headed worms) -1150 species -Parasitic -Bilaterally symmetrical -Motile -Parasitic (freshwater) • Cycliophora -1-2 species -Discovered in 1995, found on the mouthparts of lobsters -Parasitic or commensal -Symmetry is not clear -Motile -Marine • Gastrotricha (hairybacks) -790 species -Detritivores -Motile -Marine and freshwater • Gnathostomulida (jaw worms) -100 species -Detritivore -Motile (via cilia) -Marine • *Platyhelminthes (flatworms) -25,000 species -Predators or parasites -Motile -Moist habitats • Entoprocta (“anus inside”) -150 species -Filter feeding -Sessile and colonial -Mostly marine • *Mollusca (mollusks) -85,000 species -More varied forms than any other phylum -Predatory, filter feeding, detritivores -Both motile and sessile -Marine, freshwater, terrestrial • Sipunculida (peanut worms) -320 species -Filter feeding -Motile -Marine • Brachiopoda (lamp shells) -330 species -Filter feeding -Sessile -Marine • Phoronida (horseshoe worms) -25 species -Filter feeding -Sessile -Marine • Ectoprocta/Bryzoa (moss animals “anus outside”) -4,000 species -Filter feeding -Sessile -Mostly marine • Nemertea (ribbon worms) -1,800 species -Predatory and parasitic -Motile -Mostly marine, some freshwater and terrestrial • *Annelida (segmented worms) -22,000 species -Predatory, filter feeding, detritivores, sanguivores -Both motile and sessile -Marine, freshwater, terrestrial • Priapulida (penis worm) -16 species -Detritivore -Motile -Marine • Kinorhyncha (mud dragons) -Detritivore/predatory -Motile -Marina • Loricifera -120 species -Discovered in 1983 in anoxic, deep sea brine -No mitochondria -Feeding style unknown -Sessile -Marine • Nematomorpha (horsehair worms) -2,000 species -Parasitic -Motile -Freshwater or moist habitats • *Nematoda (roundworms) -15,000 species or up to 1 million -Half parasitic, half free living -Motile -Nearly all habitats and all elevations • Chaetognatha (arrow worms) -120 species -Predatory -Motile -Marine planktonic • Tardigrada (water bears) -1,150 species -Predatory -Motile -Moist habitats, extreme environments • Onychophora (velvet worms) -180 species -Predatory -Motile -Terrestrial • *Arthropoda (arthropods) -Many millions -Every feeding style imaginable -Motile -Marine, freshwater, terrestrial • What are the patterns you observe in the diversity of animal phyla? -Most phyla live in marine habitats, however, terrestrial phyla tend to have more overall diversity Animal Taxa: Invertebrates II (Lophotrochozoa) • Three major clades of Bilateria -Deuterostomia, Lophotrochozoa, Ecdysozoa • Lophotrochozoa -United by molecular characters -Named for two morphological characters that are not universal; in other words, not all members of Lophotrochozoa have the two characters for which they are named ~Lophophore-feeding morphology ~Trochophore larvae-larval morphology -Most diverse body plans -Largest number of phyla -Platyhelminthes-flatworms (25,000 species) ~Predators or parasites ~Motile ~Moist habitats, including terrestrial, freshwater, marine ~Acoelomate ~Flattened bodies increase surface area to volume ratio ~Gas exchange and diffusion of nitrogenous wastes across body surface ~Gastrovascular cavity (not a tube) -Have no anus ~More than half are parasitic, some with complex life cycles ~Complex life cycles -Schistosomiasis 2 nd only to malaria as far as devastating infectious diseases to humans go -Definitive host (a human; where the organism sexually reproduces) -Intermediate host(s) (often a snail; where the larvae produced in the definitive host develop/mature, after which they go back out to find the definitive host again) -Mollusca-molluscs (>85,000 species) ~More varied forms than any other phylum ~Predatory, filter-feeding, detritivores ~Motile and sessile ~Marine, freshwater, terrestrial ~Second only to arthropods in diversity ~Soft bodied with a hardened calcium carbonate shell (sometimes reduced) ~Shared body plan in spite of all looking very different (foot, visceral mass, mantle) (see textbook figure 33.15) ~Radula ~80% snails and slugs ~Cephalopods are most neurologically advanced invertebrates ~Some are quite toxic (blue-ringed octopus, cone snails) ~Most endangered group of animals (see textbook figure 33.21) ~Gastropods -Snails and slugs -Marine, terrestrial, freshwater -Foot is used for locomotion -Visceral mass is the gut -Mantle secretes the calcium carbonate shell ~Bivalves -Clams, mussels, oysters, etc. -Marine and freshwater -Bivalve=two shells (secreted by the mantle) -Foot holds them in one place -Visceral mass is the gut ~Cephalopods -Octopuses, squids, nautilus -Camouflage and chromatophores -Neurologically advance-eye, behavior, intelligence -Usually no calcium carbonate shell-sometimes internally (a greatly reduced mantle can be found near that) -Visceral mass is the gut -Foot is modified-tentacles and siphon -Annelida-segmented or ringed worms (22,000 species) ~Predatory, filter feeding, detritivores, sanguivores ~Motile and sessile ~Marine, freshwater, terrestrial ~Chaetae-bristles made of chitin ~Predators, grazers, filter-feeders, parasites ~Marine worms -Errantians (move around on their own) -Sedentarians (just sit in one place) ~Leeches -Secrete anesthetics and hirudin, which dissolves clots ~Earthworms -Circulate nutrients and aerate soil -Most common North American earthworms are not native and have transformed ecosystems Animal Taxa: Invertebrates III (Ecdysozoa) • Ecdysozoa -Defined by molecular evidence -Common morphological character that unites Ecdysozoa-ecdysis-external covering (cuticle or exoskeleton) is molted with growth -Most diverse animal group -Nematoda-roundworms (15,000 species or up to 1 million) ~15,000 recognized species, but estimated up to 1 million in actuality ~Half parasitic, half free-living ~Motile ~Nearly all habitats and elevations ~Important in decomposition and nutrient cycling ~Caenorhabditis elegans -1 mm long, simple organism -Important model organism in many research fields -959 total cells in adults-all mapped -Arthropoda-arthropods (many millions) ~Every feeding style imaginable ~Motile ~Marine, freshwater, terrestrial ~Most successful of all animal phyla-make up 2 out of every 3 species ~Characteristics of Arthropoda -“arthro”=joint -“pod”=foot -Segmented body -Paired limbs on segments -Hard exoskeleton (chitin) -Jointed appendages -Open circulatory system (hemolymph circulates through hemocoel) -Chelicerata-spiders, mites, scorpions, etc. ~Get their name because all of them have chelicerae (feeding appendages, often venomous) ~Cephalothorax ~Abdomen ~4 pairs of walking legs ~Pedipalps ~Behavior can be very complex -Crustacea-crabs, shrimp, amphipods, barnacles, etc. ~Many pairs of walking legs (great variation among species) ~Antennae ~Cephalon, thorax, abdomen ~Copepods may be the most numerous of animals on Earth ~Barnacles have to get creative: sessile and sexual hermaphroditism, sperm casting, very large intromittent organs -Insecta-insects (beetles, butterflies, ants, bees, cockroaches, flies, etc. ~Abdomen, thorax, head ~Antennae ~Wings (have true flight-can propel themselves through the air, not just gliding flight) ~Three pairs of walking legs ~Metamorphosis-a form of development (complete metamorphosis is when an organisms completely changes between larva and adult; incomplete metamorphosis is when there is no significant changes between larva and adult; see textbook figure 33.41) ~Why aren’t insects larger? An evolutionary constraint -The oxygen content of the air has changed over time; oxygen concentrations used to be much higher than they are today, and, consequently, insects used to be much larger Animal Taxa: Vertebrates I (Chordate Evolution to Amniotes) (see textbook figure 34.2) • Deuterostomia -Defined by molecular evidence -Deuterostome development -Echinoderms-starfish, sea urchins, sea cucumbers (~7,000 species) ~Predators and filter-feeders ~Motile ~Marine -Chordata-chordates (~65,000 species) ~All feeding styles ~Motile and sessile ~Nearly all habitats and all elevations throughout the world ~4 things that bind all chordates together (see textbook figure 34.3) -Notochord, dorsal hollow nerve cord, pharyngeal slits, post anal tail ~Notochord-flexible rodin chordate embryos, becomes spine in vertebrates ~Pharyngeal slits-develop into gills and eventually elements of the head, jaw, and ears ~Cephalochordata (see textbook figure 34.4) ~Urochordata (see textbook figure 34.5) -Vertebrates ~Duplication of Hox genes, possibly useful in increasingly complex body plans ~Bony vertebrae (usually surrounding spinal cord) -Gnathostomes (“jawed mouth”) ~Jaws-arose from support structure for pharyngeal slits (see textbook figure 34.12) ~More gene duplication ~Enhanced smell and vision ~Lateral line system -Osteichthyes (majority of vertebrates)=”bony fish” ~Ossified endoskeleton ~Actinopterygii -Ray finned fishes; most diverse vertebrate group; over 30,000 species (see textbook figure 34.15, 34.16) -In all aquatic habitats -From 8 mm to 11 m in length -Any possible aquatic niche -Lobe fins (Sarcopterygii) (see textbook figure 34.17) ~Lobed fins with bony and muscular support -Tetrapods ~4 limbs with digits (see textbook figure 34.20) ~Adults lack gills ~Vertebrae in neck permit head movement ~Pelvic girdle fused to spine ~Amphibia -Frogs and toads-5,000 species ~One of the most diverse vertebrates globally ~Many habitats ~Often specialized for leaping ~Tadpoles=aquatic larvae -Salamanders and newts-700 species ~Northern hemisphere ~Temperate ~Predators ~Aquatic larvae -Caecilians-200 species ~Burrowing ~Soil dwelling ~Tropical ~Viviparous -Amniotes (see textbook figure 34.24) ~Amniotic egg-specialized extraembryonic membranes (+shell) (see textbook figure 34.25) ~Ventilate with rib cage ~Reptilia -20,500 species -Scales composed of keratin -Shelled eggs on land/ovoviviparity -Internal fertilization -Ectothermic + endothermic • Evolution of limbless forms -If a tetrapod lacks limbs, is it still a tetrapod? ~Yes, because the term tetrapod just refers to ancestry Animal Taxa: Vertebrates II (Mammals and Metabolic Trade-offs) • Amniotes -Reptilia + Mammalia -Extra embryonic membranes protect embryo from desiccation ~Terrestrial habitats can be colonized • 3 Main Groups of Mammals (see textbook figure 34.40) -Monotremes (5 species) -Marsupials (324 species) -Eutherians (placental mammals; 5,010 species) • Mammalia -Hair -Young fed with milk produced by modified sweat glands (mammary glands) -Sound conducted through middle ear by 3 bones (malleus, incus, stapes) -Each side of lower jaw made up of a single bone, the dentary • Hair -No other animal group has it -Found on all mammals at some point in development -Keratin -Molt patterns -Complex anatomy ~Arrector muscles ~Sebaceous glands ~Color variation ~Vibrissae vs. underfur vs. fur • Young fed with milk produced by modified sweat glands (mammary glands) -Also not found in any other group (with the exception of pigeons and caecilians) -Intense parental investment in offspring -Obligates female parent to invest heavily (lactation is often more expensive than gestation) Animal Taxa: Vertebrates II (Mammals and Metabolic Trade-offs) ctn. • Mammalia -Sound conducted through middle ear by 3 bones (malleus, incus, stapes) -Each side of lower jaw made up of a single bone, the dentary -Remember, our perceptions about perception are influenced by our evolutionary history. Primates are very visual. Most use olfaction and hearing more. • Mammal evolution -Pelycosaurs-evolution of homoiothermy (or homeothermy) ~Homeothermy: stable internal body temperature in spite of external influence; can be regulated behaviorally or metabolically • Thermoregulation -Homeotherm: relatively constant temperature -Poikilotherm: variable temperature -Ectotherm: uses environmental heat -Endotherm: generates metabolic heat • Trends -Larger brains -Larger and more muscles -Upright limb posture -Nocturnal habits ~All of these trends are very metabolically expensive • Metabolic expense -How to address this problem? ~Heterodonty (specialized teeth): efficiency in processing food; pre- process before it enters the stomach, most other animals don’t chew ~Secondary palate: can breathe while eating; uninterrupted oxygen supply ~Endothermy: blood vessels in fossilized bones; evidence of whiskers (maybe fur) Body Structure & Function • Form and Function -Animals must obtain nutrients and oxygen, excrete wastes, and move -Animals live in nearly every conceivable kind of environment (temperature, pressure, salinity, oxygen concentrations, light levels, selective pressures, etc.) -Natural selection acts on heritable variation to favor the most successful solutions to these challenges -So if a trait has an adaptive function (influences the successful survival and reproduction of individuals) then its form reflects its function ~Ex) Darwin’s finches -Natural selection acts on variation in bill shape and size in populations to favor particular bill morphologies well suited to particular foods -Bill shape (form) tells you what the diet is (function) -Exchange with the environment is ultimately at the cellular level- substances in solution travel across the plasma membrane of cells -How is this accomplished in complex multicellular organisms? -Reflected at all scales ~Molecular-cellular-tissues-organs-organ systems-organism -Molecular-enzyme structure and substrate specificity; phospholipid characteristics -Cell structure- cell with extensive endoplasmic reticulum and Golgi apparatus is likely to have what function? Protein synthesis ~Cell shapes -Neuron cells-function in communication -Epithelial cells-function in lining surfaces -Muscle cells-function in contraction ~Tissues- groups of cells that together serve a particular function -Embryonic tissue layers: endoderm, mesoderm ectoderm ~Give rise to 4 kinds of tissues 1. Connective-support, connect, or separate 2. Nervous-regulation, control, communication 3. Muscle-support, movement (contraction) 4. Epithelial-lining/covering -Tissues reflect function (see textbook figure 40.5) ~Example: Hydrodynamics is a physical constraint of the environment -Water is 1000x denser than air -Problem-how to travel quickly and efficiently through water -Solution-fusiforms (streamlined) body shape -Diverse organisms face similar challenges and arrive at similar solutions=convergent evolution ~Example: Increasing stride length to run fast ~Example: Evolution of flight in vertebrates -Similar physical constraints (generate lift) -Solutions reflect evolutionary constraint as well -Benefits of flight-powered flight has evolved four times (three times in vertebrates)-insects, pterosaurs, birds, bats -Problem-How to generate sufficient lift for sustained flight? -Solution ~Flight membranes ~Generally small body size ~Lighten bony elements -Specific solutions vary ~Pterodactyl-elongate single digit ~Bird-fuse distal bony elements and feathers ~Bat-elongate four digits • Locomotion -Adaptations for different forms of locomotion are based on the same basic tetrapod body plan • Form and Function: two general principles that influence form and function in organ systems -Body size and surface area to volume relationships -Homeostasis and Regulation • Body size and surface are to volume relationships -Large ~Need more food ~Take longer to mature ~Lost heat slowly ~Lose water slowly ~Reproduce slowly -Small ~Need less food ~Shorter time to maturity ~Lose heat quickly ~Lose water quickly ~Reproduce quickly -There are many consequences of body size ~While the large aren’t very subject to the environment, they have much slower cycles ~While the small have fast cycles, they are very subject to environmental extremes -Example: body mass (size) and metabolic rate (see textbook figure 40.20) ~Metabolic rate-oxygen consumption per unit of time=a measure of metabolic activity ~Metabolic rates vary with activity, so basal metabolic rate is measured (at rest) ~What is the relationship between body mass and basal metabolic rate? -Bigger animals eat less proportionally because they generally have a slower metabolism -Example: Relationship between body mass and lifespan ~What is the relationship between body mass and lifespan? -Larger animals tend to live longer -As volume increases, surface area increases less -Surface area is critical for exchange -Example: salmon hatchlings ~Oxygen exchange across skin and gills ~At hatching, most oxygen exchange is across the skin ~As they grow, the gills take over -Every cell must exchange with its environment (see textbook figure 40.3) -Complex animals: vastly increased surface areas for exchange of nutrients, oxygen, and wastes (see textbook figure 40.4) -Adaptations to increase surface area ~Flattening ~Folding ~Branching Regulating Internal Environments: Homeostasis and Thermoregulation • Homeostasis and Regulation -Conformers vs. Regulators (see textbook figure 40.7) ~Conformers-conform to the environment; as the environmental temperature changes, so does the body temperature ~Regulators-don’t conform to the environment; as the environmental temperature changes, body temperature stays relatively the same -Homeostasis: maintaining internal chemical and physical environments within a tolerable range, independent of external environmental states -Why is homeostasis important? ~Enzyme function is impacted by temperature, pH, other reactants, etc. ~Other chemical reactions in the body are sensitive to conditions ~Extremes also destroy proteins (high heat, pH) and cells (freezing, high heat) -Metabolic rate of a thermoconformer ~Do thermoconformers operate equally well at all temperatures? -No, thermoconformers have an optimal range of metabolic activity that is influenced by environmental temperatures ~Acclimatization-organisms adjust to gradual environmental changes to maintain optimal (or near optimal) performance (see textbook figure 40.10) -Homeostasis: How is it maintained? ~Set point-optimal temperature ~Stimulus-a variation from optimal temperature ~Sensor/control center-senses the stimulus and regulates response ~Response-brings temperature back to optimal ~Negative feedback-response is to minimize the effect- this is the feedback mechanism used to maintain homeostasis ~Positive feedback- response is to amplify the effect -Thermoregulation (thermoregulators): temperature maintained within a normal range ~Example: circadian rhythms-normal daily variation in body temperature (see textbook figure 40.9) • Energetic trade offs of ectothermy and endothermy? -Able to maintain activity in different conditions? ~Endotherms are able to do this much more efficiently than ectoderms -Require more or less energy? ~Ectotherms require substantially less energy than endotherms • Mechanisms of Heat Exchange (see textbook figure 40.12) -Conduction: direct contact between solids -Convection: direct contact between solid and gas or liquid -Radiation: no direct contact -Evaporation: high heat of vaporization; a special property of water -In which direction does heat flow? ~Heat always flows from areas of high heat to areas of low heat; from high to low; from hotter to colder temperatures • Generating and retaining heat -Insulation helps retain heat in mammals and birds -Behavioral heat absorption and regulation -Circulatory adaptations ~Vasodilation and vasoconstriction-delivering different amounts of heated blood to skin surface to heat or cool ~Countercurrent heat exchange (see textbook figure 40.13) -Evaporative heat loss -Metabolic heat production ~Shivering and non-shivering thermogenesis ~Some ectotherms use shivering thermogenesis to generate heat • Thermoregulation and energy conservation -Torpor: a state of decrease physiological activity ~Small endotherms (birds and mammals) that are active, with high metabolic rates ~Daily pattern -Hibernation: seasonal state of reduced physiological activity ~Mostly mammals ~Aestivation-“summer hibernation”- often facultative ~”Set point” is greatly reduced, sometimes to nearly 0 degrees Celsius ~Often accompanied by periodic arousals -Adaptive heterothermy ~The ability of an endothermic animal to allow its body temperature to fluctuate in response to some form of environmental stress, saving significant amount of energy and water ~Heterothermy: endothermic animals allow body temperature to fluctuate in response to an environmental stress (hibernation, aestivation, torpor, daily changes) Dietary Strategies and Digestion: Tongues, Teeth, and Venom • Dietary Strategies and Digestion -Remember that all animals are ingestive heterotrophs -Why eat? ~Obtain chemical energy (sugars; respiration) ~Obtain organic molecules (building blocks for tissues) ~Obtain essential nutrients-cannot synthesize, must obtain from food -Essential amino acids-for protein synthesis -Essential fatty acids-for fatty acid synthesis -Vitamins-organic compounds with a variety of functions; “a substance that makes you ill if you don’t eat it” -Minerals-inorganic compounds, diverse functions, includes electrolytes -This is all done to support ~Survival ~Growth ~Reproduction -3 classes of molecules are sources of chemical energy, building blocks, and essential nutrients ~Carbohydrates-sugars and polymers of sugars, including glycogen and cellulose ~Proteins-polymers of amino acids ~Lipids-complex carbon molecules that are hydrophobic (fats-made up of fatty acids, phospholipids, steroids) Clicker Question • Nearly all animal phyla evolved in which era? Cambrian • Do jellyfish have a coelom? No • Where did protostome development evolve? Lophotrochozoa and Ecdysozoa • Where did triploblastic tissue organization arise? Deuterostomia, Lophotrochozoa, Ecdysozoa • Where did deuterostome development arise? Deuterostomia • Although mollusks have the most varied body forms of any animal phylum, they all share a common body plan that includes a visceral mass, foot, and mantle • The phylum Arthropoda is made up of these living groups: Crustaceans (including insects), chelicerates, and myriapods • Insect size is most likely limited by the maximum distance that oxygen can efficiently diffuse into tissue • In chordates, some of the pharyngeal slits become the jaw/mouth in vertebrates • The hallmark characteristics of mammals are three inner ear bones, a single lower jaw bone, hair, and mammary glands • The most diverse animal phyla have colonized terrestrial habitats • Compared to their amphibian relatives, amniotes have reduced their reliance on water in their reproductive cycle • Lophotrochozoa, Ecdysozoa, and Deuterostomia are all made up of animal phyla that share molecular characteristics • All mammals are endothermic, most are homeothermic, some are heterothermic Homework Quiz 6 • All animals are multicellular, ingestive, heterotrophs with a diploid dominant life cycle • Lophotrochozoa, Ecdysozoa, and Deuterostomia are all made up of animal phyla that share molecular characteristics • Examples of lophotrochozoans are octopuses, slugs, leeches, flatworms • Compared to their amphibian relatives, amniotes have reduced their reliance on water in their reproductive cycle • Deuterostome development is characterized by spiral and determinate cleavage, blastopore forms the mouth Homework Quiz 7 • What is the importance of consuming an adequate amount of proteins in the diet? Proteins serve a variety of functions, and the body does not store excess quantities of protein • Evolutionary adaptations that help diverse animals directly exchange matter between cells an the environment include an external respiratory surface, a small body size, and a two-cell-layered body • Penguins, seals, and tuna have body forms that permit rapid swimming, because the shape is a convergent evolutionary solution, which reduces drag while swimming • Hibernation and torpor are similar because they allow animals to escape seasonal climate changes and conserve metabolic energy • Ectothermic homeotherms are able to maintain a constant body temperature because they are found in environments with temperatures that don’t change
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