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211 Cards in this Set
- Front
- Back
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Three major domains
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1. Bacteria
2. Archaea 3. Eukarya |
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Evolution
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moderation of a species over generations
*(decent with modification) or common ancestry |
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Charles Darwin
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Natural Selection
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Natural Selection
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process by which individuals with certain traits survive and reproduce more than individuals without those traits
NOT survival of the fittest |
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Tenets of Natural Selection
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1. Individuals in a population for variation in traits
2. Variable traits must be heritable (genetically transferable to offspring) 3. Individuals must have an unequal survival and reproduction success |
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natural selection acts on ___
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individuals
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evolutionary change acts on ____
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populations over time
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Fitness
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the ability of an individual to produce offspring
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higher fitness =
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greater/ more often reproduction
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adaptation
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an inherited trait that increases the fitness of an individual in a specific environment
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Evidence of natural selection
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similarities of related species
*darwin noticed variations in related species living in different locations |
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Evidence of evolution
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Fossil records
intermediate forms comparative anatomy molecular evidence |
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Fossil Records
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new records are found all the time
say that earth is approx. 4.6 billion years old |
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fossilization occurs when
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an organism is buried in sediment
calcium in bone or other hard tissue is mineralized *provide a detailed account of evolutionary transitions |
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Probability of fossilization is _____ due to ...
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low; because of decomposition and scavengers
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Evolution of whales from __
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hoofed mammals
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Cousin of the whales is
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Ambulocetus
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Intermediate forms...
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the different evolutionary forms of animals since not all traits evolve at once
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Vestigial Structure
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nonfunctional trait is shared due to common ancestry
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Homologous structures
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have a same evolutionary origin but different structure and function (inherited)
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Example of homologous structures
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human arm, cat leg, bat wing
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Analogous structures
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have similar structure and funtion, but have a different evolutionary origin (not inherited)
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example of analogous structures
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butterfly wing, bat wing, bird wing: all wings however not all of them are derived from the same ancestor
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Parallel evolution (convergent evolution)
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development of a trait in related species that evolve from a common ancestor but different clade
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DNA and protein structures have led to the development of...
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more accurate phylogenetic trees
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Mendel developed theories of...
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genetic inheritence
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Phylogeny
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the evolutionary history of the species or group of related species
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What does the discipline of systematics do?
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classifies organisms and determines their evolutionary relationships
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what are used to infer evolutionary relationships?
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fossils, molecular and genetic data
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Taxonomy
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the ordered division and naming of organisms
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What did Linnaeus do?
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Published system of taxonomy based on similarities among organisms
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Binomial nomenclature
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two part names for species
*Genus and species epithet = speices |
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Hierarchal classification
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taxonomic groups arranged from broad to narrow
(Domain, kingdom, phylum, class, order, family, genus, species) |
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systematics depict...
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evolutionary relationships in branching phylogenetic trees
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A phylogenetic tree depicts...
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a hypothesis about evolutionary relationships based on shared derived characeristics
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parsimony
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fewest number of changes is the most likely
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evolutionary reversal
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a loss of a trait over time (usually present and then lost)
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key to interpreting a phylogeny -
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look at how recently a species share a common ancestor
(similarity may not accurately predict evolutionary relationhship) |
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Why would simliarity not predict evolutionary relationships?
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rates of evolution vary
evolution may not be unidirectional (traits can be lost) evolution does not always occur as a divergence event |
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Derived characteristics
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similarity inherited from most recent common ancestor of an entire group
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Ancestral characteristics
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similarity that arose prior to common ancestor of group
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In cladistics what are considered informative of evolutionary relationships?
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only shared derived characteristics
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characters
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can be any aspect of the phenotype
Morphology behavior physiology DNA |
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amniote
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amniotic membrane
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Ancestral vs derived characteristics
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Presence of hair - shared derived character of mammals
Presence of lungs in mammals - ancestral trait; present in ampibians reptiles |
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Shared derived feature suggests
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all mammal species with the feature share a common ancestor that existed more recently than the common ancestor of all mammals, amphibians, and reptiles
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Polarize characteristics
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determine if it is ancestral or derived
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outgroup
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species or group that is closely related to,but not a member of the group under study
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Cladogram
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depicts a hypothesis of evolutionary relationships
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clade
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name for a group that share a common ancestor
*Human is a clade within mammal |
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Synapomorphy
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derived character shared by clade members only
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Amniotes are a clade
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amniotic membrane is a synapomorphy
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Homoplasy
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a shared character state, not inherited from a common ancestor
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Phylogenetic trees do not depict
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when a species evolved or how much genetic change occured
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We cannot assume that a taxon evolved from
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the taxon next to it
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homoplasy
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convergent evolution/ parallel evolution
(i.e wing of bat and bird; both function the same but are not form the same ancestor) |
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Homologous traits
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shared trait and a common ancestor
(i.e flipper of whale and wings of bats; both share the same trait and a common ancestor) |
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Animals evolved from
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colonial choanoflagellate ancestor
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heterotroph
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have a common food from a different source
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Key evolutionary transitions in animal evolution
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tissues, nervous system, body cavity, development, segmentation
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with the exception of ___ all animals have tissues
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sponges
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epithelium
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group of sponges that layer cells that cover the outer surface of the body
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Embryonic tissues in animals are organized into -
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germ layers
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ectoderm
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outer germ layer (skin and nervous system)
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endoderm
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inner germ layer (lining of digestive tract)
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mesoderm
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middle germ layer (circulatory system, bone, muscles, and most organs)
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Diploblast
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contains only two tissue layers (ectoderm and endoderm)
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Triploblast
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contains all three germ layers (mesoderm, ectoderm, endoderm)
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the only diploblasts are -
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cnidaria and ctenophora
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All animals are
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triploblast (except cnidaria and ctenophora)
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sponges dont contian
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neurons
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what type of nervous system do cnidarians and ctenophores contain?
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nerve net (diffuse neurons in hydra)
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All organisms contain (type of nervous system)
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central nervous system (CNS)
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Central nervous system
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neurons are clustered into:
tracts or cords running throughout body masses called ganglia |
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Ganglia
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masses of neurons
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What type of symmetry do sponges contain?
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asymmetricl (no symmetry(
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Radial symmetry
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body parts arranged around a central axis and can be bisected into two equal halves on any 2D plane
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Anterior
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front of animal
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Posterior
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back of animal
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Dorsal
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top of animal
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ventral
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botom of animal
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Bilaterally symmetrical
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body has a right and left halves that are a mirror images of each other on the sagittal plane
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sagittal plane
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bisects animal from anterior to posterior
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How does symmetry relate to the nervous system?
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Radially = nerve net
Bilaterally = central nervous system |
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cephalization
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collection of nerves on the anterior end of an animal (brain)
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Eumetazoa produce
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three germ layers
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Acoelomates
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no body cavity
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pseudocoelomates
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body cavity between mesoderm and endoderm
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body cavity between mesoderm and endoderm is called
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pseudocoel
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coelomates
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body cavity entirely within the mesoderm
called coelom |
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Specification of tissue layer functions in: Acoelomates
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ectoderm - body covering
endoderm - wall of digestive cavity mesoderm - tissue filled region |
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Specification of tissue layer functions in: pseudocoelomates
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ectoderm - body covering
endoderm - digestive tract mesoderm - muscle layer |
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Specification of tissue layer functions in: coelomates
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ectoderm - body covering
endoderm - dogestive tract mesoderm - tissue layer lining coelom and suspending internal organs (must surround entire space) |
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Body cavity allowed for the development of -
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organ systems
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coelomates developed
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circulatory system to carry nutrients and remove wastes
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Open circulatory system
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blood passes from vessels into sinuses mixes with body fluids and reenters the vessels
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closed circulatory system
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blood moves continuously though vessels that are separated from body fluids
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Basic bilaterian pattern of deveopment
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Mitotic cell divisions of egg form a hollow ball of cells (blastula)
Blastula indents to form a two layer thick ball with blastopore Archenteron |
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Blastula
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hollow ball of cells formed from mitotic divisions of egg
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Blastopore
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opening to outside of blastula
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Archenteron
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primitive gut
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cleavage developmetn
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- Sperm fertilizes egg to form zygote
- Zygote undergoes cleavage (rapid cell division) - Cleavage leads to formation of a blastula - Blastula undergoes gastrulation (in-folding), forming gastrula with different layers of embryonic tissues - Gastrulation forms archenteron, which opens to outside via blastopore |
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cleavage
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rapid cell division
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gastrulaion
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in-folding
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two models of bilaterian development
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protostomes
deutrerostomes |
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protostomes
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develop mouth first from or near the blastopore
anus develops from blastopore for another region of embryo |
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deuterstomes
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anus develops first from the blastopore
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Protostomes and deuterstomes shared a common ancestor more than
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500 million years ago
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what are the two advantages of segementataion
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allows for redundant organ systems
allows from more efficient and flexible movements |
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molecular systematics
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uses unique genetic sequences within certain genes to identify clusters of related groups
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HOX genes
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genes involved in pattern formation in early embryos
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Concept of species must account for -
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looks
similarities between populations |
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sympatric species
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occurs together in an area with distinctive entities and physical differences and use different resources and behave separately
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sub species
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individuals within one species that occur in different areas may differ
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Ernest mayer developed the
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biological speices concept
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biological species concept
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species are groups of interbreeding natural populations that can't reproduce with other groups
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Reproductive isolation
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populations whose members do not mate or who cannot produce fertile offspring with each other
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Speciation
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the process by which new species are formed
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Genetic drift
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random changes may cause reproductive isolation
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two ways to create small populations
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Founder effect
population bottleneck |
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founder effect
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population begins with few individuals, low genetic variation
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population bottleneck
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large population is rapidly reproduced by a catastrophic event resulting in few individuals and low genetic variation
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Adaptive radiation
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rapid evolution resulting in many species
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Adaptive radiation occurs in
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an environment with few other speices and many resources or when a catastrophic event occurs
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Gradualism
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accumulation of small changes over time
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Punctuated equilibrium
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long periods of stability followed by periods of rapid change
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how many mass extinctions have there been?
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5 mass extinctions
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Branch point
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spot on pylogenetic tree that represents the divergence of a species
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Phylum Porifera
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sponges
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sponges (porifera)
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most lack tissues, organs and definity symmetry
marine (freshwater) larvae are free-swimming adults are stationary |
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Inner layer of sponge
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specialized flagellate cells called choanocytes (collar cells)
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central layer of sponge
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gelatinous, protein-rich matrix called the mesohyl which contains amoebocytes
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mesohyl
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gelatinous, protein-rich matrix (central layer of sponges)
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outer layer of sponge
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protective epithelium
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spongin
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tough proteins that strengthen the body of the sponge
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spicules are made of
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amoebocytes
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Suspension feeders
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capture food particles suspended in water
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choanocytes
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create water current through sponge and ingest food by phagocytosis
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phagocytosis
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water enters through pores into a cavity called the spongocoel then exits through an opening called the osculum
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spongocoel
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cavity on the interior of a sponge
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osculum
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opening at the top of a sponge
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how to sponges reproduce?
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Asexually - fragmentation (budding) and regeneration
sexually - egg and sperm |
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Gemmules
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dormant stage of sponge reproduciton, form inside mesohyl, remain after adult dies and forms a new sponge when conditions are approiate
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Hermaphrodites
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individual that functions as both a male and female
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how do sponges defend themselves?
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produce toxins
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mutualistic association
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both individuals benefit when they grow together
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Cnidarians
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almost all marine
bodies have distinct tissues (no organs) Diploblastic - ectoderm (epidermis) and endodermis (gastroderms with mesoglea(gelatinous material between tissue layers)) |
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Cnidarian body plan
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a sac with a central digestive compartment (gastrovascular cavity)
Two body forms: polyp and medusa |
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gastrovascular cavity
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central digestive compartment
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mesoglea
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gelatinous between tissue layers in cnidarians
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polyp
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cylindrical and sessile
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medusa
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umbrella shaped and free living
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Cnidarian reproduction
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polyp - sexually or asexually
medusae - sexually (form free swimming larvae called planula |
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planula
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free swimming larvae of medusae
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how do cnidarians obtain nutrients?
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extracellular digestion:
digestion begins with extracellular fragmentation in the gastrovascular cavity followed by phagocytosis and intercellular digestion |
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Protein found in gila monster helps
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type 2 diabetes
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Diffusion
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movement occurs form a high to low concentration
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what type of nervous system do cnidarians have?
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nerve net
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cnidocytes (nematocyst(
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contains a small but powerful harpoon that is used for food acquisition
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5 classes of cnidarians
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hydrozoa
scyphozoa cubozoa anthozoa staurozoa |
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hydrozoa
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most alternate between polyp and medua form
found in both marine and freshwater |
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scyphozoa
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jellies are the prevalent form
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cubozoa
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contain box jellies and have highly toxic cnidocytes
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anthozoa
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coarals and sea anemones
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staurozoa
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star jellies
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Lophotochozoans
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protostomes
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three major groups of Lophotochozoans
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flatworms
annelids mollusks |
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Flatworms
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Triploblastic
acoelomates gas exchange via diffusion |
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what are the two feeding strategies of flatworms?
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most - gastrovascular cavity (muscular contraction in pharynx break food into small bits
Tapeworms - absorb food through body walls |
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pharynx (flatworms)
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digestive tract between mouth and esophagus
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Osmoregulation
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process used to maintain water and salt concertrations for cellular functions
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flame cells (flatworms)
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water balance and excretion
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absorbtion of nutrients in flat worms
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diffusion
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Eyespot
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can distinguish light from dark
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What type of nervous system does the flatworm have?
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centralization of nervous system (ganglion present)
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Reproduction in flatworms
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hermaphroditic
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Two major groups of flatworms
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free living (turbellaria)
parasitic (neodermata) |
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Turbellaria
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freshwater, marine, and terrestrial
catch food with mucous secretions to trap prey |
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chemoreceptors
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in turbellaria - sensory structures that detect chemical signals
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Trematoda (Flukes)
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live as parasites (most life cycles involve two or more hosts
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ectoparasites
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attach to outside of other animals (host)
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endoparasites
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attach to inside of the host
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schistosoma
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schistosomiasis is a disease from the worm where the host cannot recognize it due to protein coding
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cercomeromorpha (tape worm)
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parasites in the intestines
Long flat bodies divided into 3 sections: scolex, neck and proglattids |
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scolex (cercomeromorpha)
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attachment organ
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neck (cercomeromorpha)
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unsegmented portion
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Proglottids (cercomeromorpha)
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repetitive sections
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Annelids
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segmentation
body divided internally by septa |
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segmentation
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building of body from repeated units
(allows for specilaization) |
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movement (annelids)
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hydrostatic skeleton
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hydrostatic skeleton
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annelids - each segment contains chitin bristles (chaetae) that help anchor the worm
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circulation resperation excretion (annelids)
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closed circulatory system
respiration through body surfaces excretory system is a pair of cilliated funnel shaped nephridia |
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Three classes of annelids
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Polychaeta
oligochaeta hirudinea |
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Polychaeta
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marine
have differentiated head paired parapodia on most segments sexes seperate |
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parapodia
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used in gas exchange and locomotion
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How to earthworms eat?
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eat through soil, extracting nutrients as the soil moves through the alimentary canal
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Leeches
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freshwater
flattened cross fertilize no chaetae |
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Molluska
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evolved in oceans, marine
snails, slugs, clams, octopuses and others |
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Three major parts of mollusks
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Foot - movement
mantle - creates the shell visceral mass - entire mass of organism |
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Nephridia (mollusks)
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structures that remove nitrogenous wastes
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circulatory system (mollusks)
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all have an open circulatory system (except cephalopods)
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Chiton
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polyplacophora
marine oval body and eight overlapping dorsal calcareous plates herbavore |
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snail and slugs
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gastropoda
marine heads typically have pairs of tentacles with eyes at the ends |
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During embryological development, gastropods undergo
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Torsion and coiling
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Torsion (snail)
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mantle cavity and the anus are moved from the posterior to the front near the mouth
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coiling (snail)
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spiral winding of the shell
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Bivalves
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clams, scallops, mussels, oysters
have two dorsally hinged shells |
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Siphons
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mediate water circulation in bivalves by rythmic beating of cilia
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Cephalopods
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squid octopus and nautilus
active marine predators highly developed nervous system |
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cephalopods movement
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foot has developed into a series of arms equipped with suction cups
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Chromatophores
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octopus and squid can change color using pouches and pigment called ______
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