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134 Cards in this Set
- Front
- Back
Plate Tectonics Evidence (Wegener)
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Magnetic anomolies:
reversal of magnetic poles has left magnetic stripes in rock layers deposited and Midatlantic ridge splits mirror image of stripes alternating in magnetic direction because of sea-floor spreading. Plate boundaries: transform, convergent (mountains), divergent (sea-floor spreading, rifting). Distribution of species (amount of relatedness shows what order groups we separated, ex. related marsupials live on different continents) Evidence of original supercontinent: Pangea split into Gondwana (South: Africa, S. America, Australia, Antarctica, Madagascar) and Laurasia during Jurassic period. Similar species are most closely related the more recent their respective landmasses separated |
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pleistocene overkill hypothesis
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overhunting of large animals by humans caused exticntion
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Mass extinction
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extinction of a large number of species within a short period of time, thought to be due to factors such as a catastrophic environmental change that occurs too rapidly for most species to adapt. Much faster rate than background extinction. Number/diversification of species rebounds afterward. Mass extinctions mark the ends of geological time periods.
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Background extinction
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ongoing extinction of individual species, normal evolutionary process
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Examples of Cause for Mass Extinction
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Asteroid impact. Flood basalt event (lava plume from massive volcanism). Sea-level drop.
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Dating with isotopes:
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once an organism dies, their carbon begins to decay. Measuring ratio of carbon isotopes shows how many half-lives have occurred which tells when organism died.
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Iridium
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Abnormally high amounts of iridium have been found in rocks dating to the K-T boundary between the Cretaceous and Tertiary periods (65 million years ago). This has led to a widely held view that an iridium-containing comet struck the Earth at that time, which led to the extinction of the dinosaurs and many other forms of life
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5 mass extinctions
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Extinction
event Age x10 6 yr Families (%) Genera (%) Species (%) Cretaceous 65 - 15 35 + 8 Triassic 208 22 53 80 + 4 Permian 245 51 82 95 + 2 Devonian 367 22 57 83 + 3 Ordovician 439 26 60 85 + 3 |
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Trilobites
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Make great fossils. Were around for a very long time before mass extinction during cambrian period.
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Modern Extinction Rate
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recent historical rate of
vertebrate extinctions is a little over 7,000 times greater than the background rate of extinction. 1,000-10,000 times more than at any time in the last 65 million years |
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Evidence for extinction at k-t boundary
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rocks laid down precisely at the K-T boundary contain extraordinary amounts of the metal iridium. iridium is present only in the boundary rocks and therefore was deposited in a single large spike. iridium was scattered worldwide from a cloud of debris that formed as an asteroid struck somewhere on Earth.
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Cambrian Explosion
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Vast increase in diverse forms of life. Existing small simple organisms diversified and became more complex. Fossils begin to appear
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Great Oxygen Catastrophe
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Life formed anaerobically. Some organisms did photosynthesis, creating oxygen, which was absorbed by oceans and rock. Eventually excess oxygen accumulated in atmosphere, causing mass extinction of anaerobic organisms, creation of ozone layer. Probably caused by photosynthetic cyanobacteria.
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c3 and c4 grasses
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2 types of carbon fixation used in plants. When the environment turned hot and dry, grasses went from being c3 to c4 to be more efficient (switched to an enzyme with less affinity to oxygen). Only opened stomates at night to reduce water loss. Horses co-evolved to have longer teeth that would hold up to the harder material of the c4 plants.
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Cambrian Period
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542 - 488 million years ago. Vast increase in life forms.
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3 processes changed atmosphere
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Volcanos - bulk of the atmosphere was derived from degassing of mantle early in the Earth's history
Chemical Reactions - creation of ozone layer Photosynthesis - Great Oxygen Catastrophe |
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Ozone Layer
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Created during Great Oxygen Catastrophe, essential to life because protects from harmful UV radiation
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Characteristics of Life
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Cell Structure
Metabolism Accurate Replication |
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Miller-Urey Experiment
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Created basic building blocks of life under known conditions of early earth. Chemical reactions that synthesized organic compounds (amino acids) from inorganic precursors.
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The Central Dogma
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(DNA > replication > )DNA - transcription > RNA > translation > PROTEIN. Only in special situations does RNA turn to RNA/DNA or DNA turn to PROTEIN. Protein can never be transferred into anything else.
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Primordial Soup Hypothesis
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A liquid rich in organic compounds and providing favorable conditions for the emergence and growth of life forms. Oceans of primordial soup are thought to have covered the Earth during the Precambrian Eon billions of years ago. The organic compounds in the primordial soup, such as amino acids, may have been produced by reactions in the Earth's early atmosphere, which was probably rich in methane and ammonia. The complex self-replicating organic molecules that were the precursors to life on Earth may have developed in this primordial soup.
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Prebiotic Molecule
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A molecule that is believed to be involved in the processes leading to the origin of life.
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Heterotroph
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eats other things
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Autotroph
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makes its own food
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conjugation
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one of three types of hoizontal gene transfer, transfer of genetic material between two bacterial cells in direct contact
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transformation
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one of three types of horizontal gene transfer, change in genetic makeup resulting from the direct uptake of exogenous DNA from its surrounding and taken up through the cell membrane
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transduction
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one of three processes of horizontal gene transfer, process by which DNA is transferred from one bacterium to another by a virus. injection of foreign DNA by a bacteriophage into the host.
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horizontal gene transfer
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processes by which exogenous genetic material may be introduced into bacterial cell (transformation, transduction, conjugation)
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3 domains of organisms
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eukarya, archea, bacteria
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phylogeny (2 types)
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evolutionary development of a species (reticulate and divergent)
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reticulate phylogeny
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complicated net of species, happens when there can be horizontal gene transfer, can be found in archea and bacteria
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divergent phylogeny
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tree like evolutionary history of species
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endosymbiosis
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a type of symbiosis in which one organism lives inside the other, the two typically behaving as a single organism. (this led to mitochondria and chloroplasts becoming organelles)
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Primary endosymbiosis
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involves the engulfment of a bacterium by another free living organism.
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Secondary endosymbiosis
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occurs when the product of primary endosymbiosis is itself engulfed and retained by another free living eukaryote
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Evidence of bacterial origin of mitochondria and chloroplasts
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Have 2 or more plasma membranes
Have own genome, replicate separately from host, single circular model, no histones associated with dna Have own protein synthesizing material Some genes transferred to nucleus |
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Phagotrophs
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organisms that engulf solid material with cell membrane to digest
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Osmotrophs
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organisms who use the uptake of dissolved organic compounds by osmosis for nutrition
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Prokaryote
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unicellular organism with no nucleus (bacteria and archea)
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extremophiles
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Bacteria and Archaea that can live and thrive in environments with extreme conditions such as high or low temperatures and pH levels, high salt concentrations, and high pressure.
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eutrophication
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The process by which a body of water becomes excessively rich in dissolved nutrients, resulting in increased primary productivity that often leads to a deficiency in dissolved oxygen. excessive plant growth and decay, favouring simple algae and plankton over other more complicated plants, and causes a severe reduction in water quality.
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PCR (polymerase chain reaction)
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Laboratory technique used to make numerous copies of specific DNA segments quickly and accurately
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Xenologous genes
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homologous due to horizontal gene transfer
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What allows for the development of antibiotic resistance?
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Lateral/Horizontal gene transfer (prokaryotes)
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Pathogen
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biological agent that causes disease in a host
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Endospore
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Method of gene preservation. Dormant form of bacteria which can withstand harsh environmental conditions for long periods of time in order to continue the species once conditions are favorable again
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Endosymbiosis: Vertical Transmission
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Passed from parent to offspring
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Endosymbiosis: Horizontal Transmission
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Found in environment
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Endosymbiosis: Mixture of horizontal and vertical transmission
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Passed from other members of species
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Mutualism
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symbiosis where both parties benefit. This is how Chloroplasts and Mitochondria became cellular organelles.
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Multicellulatiry benefits
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1) Staying in one place and living in currents (being able to feed in currents, like a stream)
2) Can move where they want and more quickly 3) Can eat larger prey and escape predation 4) Cells can specialize (muscles, digestion, brain…) |
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Multicellularity problems
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basal metabolic rate and flux will limit cell size
diffusion is slow large cells have greater metabolic needs cooperation(from kin selection) larger means need for circulatory system then circulatory tissue increased food demand |
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How is a multicellular colony different that a multicellular individual?
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Individual: once you get germ-soma differentiation
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Fick's law
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flux = -(permeability of a membrane)(area)(concentration gradient)
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Basal metabolic rate
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minimum energy production for a cell to survive
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synapomorphy
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A synapomorphy is a shared trait found among two or more taxa and their most recent common ancestor, whose ancestor in turn does not possess the trait.
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Colony vs Individual
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Individual once there is germ-soma differentiation
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germline sequestration
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reduces mutation rate because of mitotic arrest, metabloic inactivity reduces oxidative activity
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Porifera and how they cope with diffusion time and rate
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"Pore bearer." Their bodies consist of jelly-like mesohyl sandwiched between two thin layers of cells. rely on maintaining a constant water flow through their bodies to obtain food and oxygen and to remove wastes using specialized cells, and the shapes of their bodies are adapted to maximize the efficiency of the water flow. (SPONGES)
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Platyhelminthes and how they cope with diffusion rate and time
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Exchange gases elusively by diffusion. This explains their flat shape to maximize surface area. (FLATWORMS!)
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Outgroup
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start with this species to build a cladogram
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Monophyletic group
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group with common descent from one ancestor
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Paraphyletic group
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group containing a common ancestor but leaving out some descendents
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Segmentation
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the division of some animal and plant body plans into a series of repetitive segments.
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Tagmosis
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The evolutionary process that changes a segmented organism into 3 main specialized segments (Head, thorax, abdomen) by fusing and modifying segments
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Radial symmetry
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no sides, just top and bottom. if cut like a pie, the slices would be identical. (anemone, jellyfish, sea stars)
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Bilateral symmetry
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symmetrical about line down the middle. left and right sides are mirror image.
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acoelomate
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no body cavity. semi-solid tissue holds organs in place.
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pseudocoelomate
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fully functional, partly lined with mesoderm body cavity. Organs are held in place loosely, they are not as well organized as in a coelomate. All pseudocoelomates are protostomes.
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coelomate
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fluid filled body cavity with complete lining with mesoderm. allows organs to be attached to each other so that they can be suspended in a particular order while still being able to move freely within the cavity. Most bilateral animals, including all the vertebrates, are coelomates
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Blind gut
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digestive cavity having only one opening
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Compete gut
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digestive cavity with 2 openings: mouth and anus
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Protostomata
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Blastopore becomes mouth.
Spiral/determinate Cleavage: fate of cells determined as they are produced. (asymmetrical cell division: cell creates 2 daughters with 2 different fates) |
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deueterostomata
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Blastopore becomes anus.
Radial/Indeterminate Cleavage: fate of cells is undetermined through 8-cell stage, each contain enough information to build complete organism. (symmetrical cell division: cell creates 2 daughters with equivalent fates) |
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diploblast
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a condition of the blastula in which there are two primary germ layers: the ectoderm and endoderm. The endoderm allows them to develop true tissue, including tissue associated with the gut and associated glands. The ectoderm gives rise to the epidermis, the nervous tissue, and if present, nephridia. (cnidaria and ctenophora)
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triploblast
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more complex animals than diploblasts (from flat worms to humans) are triploblastic with three germ layers (a mesoderm as well as ectoderm and endoderm). The mesoderm allows them to develop true organs.
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totipotent
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cell has the capacity to form an entire organism of differentiated cells
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anhydrobiosis
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dormant with no water (form of diapause)
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3 domains
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eukarya, archea, bacteria
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A eukaryotic kingdom: Animalia. Also known as...
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Metazoa
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blastula
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sphere of cells that is early form of embryo
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gastrula
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stage after blastula, layered sac with endoderm, exoderm, and mesoderm. connects to outside by blastopore.
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blastopore
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in a gastrula, connects archenteron to outside.
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archenteron
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inside cavity of gastrula that will become the gut
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needs to live on land
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Ability to breath; must internalize lungs (initially swim bladders)
Structural support Ossification Storage hypothesis Predation Movement Jointed appendages |
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holometabola
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complete metamorphosis in life cycle
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hemimetabola
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incomplete metamorphasis in life cycle
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amniotes
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egg has everything for offspring except oxygen. mammals, hard egg laying things.
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amnion
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closest membrane to embryo
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chorion
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outermost membrane of egg, shell
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yolk
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nutrient rich cells for food for young in egg
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amphibian egg
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gelatinous covering, laid in water, gas exchange by diffusion
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Oviparity
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lay eggs with little or no embryonic development within mother
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Vivipary
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embryo develops inside mother, nourished by mother not yolk (humans!)
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Oviviviparity
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egg remaind in mother until hatch or about to hatch, still gets nourishment from yolk
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Characteristics of mammals
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Female lactation
Sweat glands Fur, hair 3 inner ear bones Neocortex region of the brain |
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3 types of mammals
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Eutheria (placental mammals)
Marsupials ( Montremata |
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monotremata
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3 species only, all live in australia: platypus
Egg laying, hold on belly until hatch, then baby sits in fold of skins where mothers pores secret nourishment |
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marsupials
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Young climb up right after born, milk secreting glands in pouch
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placental mammals
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Union of embryonic and maternal tissues
Placentas lack yolk but retain chorion and amnion |
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histotrophic
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reliant on maternal milk... probably evolved into placenta
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terrestrial egg
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Water repellant covering but permeable to gases but not to water
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preadaptations to life on land
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Gills interanalized
Bones created Apendages |
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ossification
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cartilage evolved into bone, maybe as storage device for calcium
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Porifera
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no true tissues organs or symmetry, sponges, suspension feeders, hemaphrodites, have choamocytes (flagellated cells which creat flow of water through poresto bring nutrients and oxygen)
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Cnidaria
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radial symmetry, diploblastic, have nematocysts (stinging cells used to spear prey)
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choamocytes
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in porifera, flagellated cells which creat flow of water through poresto bring nutrients and oxygen
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nematocysts
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in cnidaria: stinging cells used to spear prey
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platyhelmenthes
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acoelomate, can grow whole self from piece, flatworms, incomplete digestion
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nematoda
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pseudocoelomate, round worms, growth by molting
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echinodermata
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coelomate, deuterosome, water vascular system (tube feet:used for feeding, pulling apart shells, moving), (starfish, sea cucumbers, brittle stars), radial symmetry but larva have bilateral symmetry, adults have endoskeleton of calcium carbonate
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water vascular system
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in echinodermata: tube feet:used for feeding, pulling apart shells, moving)
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chordata
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deuterosome development, Notochord (structural support-vertabrae), Dorsal hollow nerve chord (ends in brain), Pharyngeal slits in some (pumps water through body filtering out food), 3 subphyla: urochordata(no head), cephalochordata, craniata)
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mollusca
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protosome development, mantle tissue which often grows shell, (snails, slugs, mussles, octopus), 3 body parts: mantle(dorsal body wall), muscular foot (contains balance organ and grips things), visceral mass contains internal organs
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annelida
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protosome development, segmentation, no jointed appendages, segmented worms
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arthropoda
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protosome development, specialized segmentation> tagmosis, jointed appendages, exoskeleton of cuticle, 3 big groups: crustacea, insecta, chelicerata
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rotifers
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clonal females, never male, can go into diapuase (anhydrobiosis) for mad long which can rid them of pathogens
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why have rotifers been asexual so long?
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many benefits to being asexual but one problem is dealing with pathogens, rotifers solve this by going dormant for long periods of time
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Paedomorphosis
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the resemblance of an adult individual to its juvenile form
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development of lungs
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probably originated from air bladder in fish (physoclistous), had to overcome challenges: need lots of surface area and limit water loss
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Life needed ____ to go from water to land
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Need: ability to breath and minimize water loss so you don’t dry out, structural support, movement: capture food and escape predators
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Evolution of insects
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Origin of hexapods, wings, wing folding, complete metamorphasis, co-evolved with plants
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Insects so successful because:
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- Wings
- Ability to fold wings behind back (pterygota) Complete metamorphosis (homometabolous) |
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costs of being sexual
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- Male production in sexual populations entails an ecological cost
- Cost of meiosis (decreased relatedness) - "bet hedging" (forego high success to have predicatability) |
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Benefits of being sexual
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recombination
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Protostomes (stoma = mouth)
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Early development: blastopore becomes mouth
Assymetrical cleavage Cell fate determined by 8th cell |
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Deuterostomes
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Early development: blastopore becomes anus
Radial/symmetrical cleavage Cell fate indetermined by 8th cell |
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Coelomate
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cavity between gut and bodywall
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gut
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cavity open to outside
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diploplast
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endoderm and ectoderm
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characteristics of animalia/metazoa
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- Multicellular
- Heterotrophic - Collagen (usually) (25-35% of whole body protien) - Unique muscle and nervous tissues - Lifecycle with diploid phase dominant |
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Plastids
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double membrane bounded organelle usually involved in synthesis and storage of food. chloroplasts are one kind.
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peptidoglycan
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found in cell wall of bacteria only. also bacteria have no nucleus.
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bet-hedging .
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The behavioural response of a species population to a K-selecting environment in which occasional fluctuations in conditions affect the mortality rate of juveniles to a much greater extent than of adults. In such a situation adults release young into several different environments to maximize the chance that some will survive
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