Term
| What is a biological tissue? What must and organism be to have tissue? |
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Definition
An aggregate of cells in an organism that have similar structure or function
Must be multicellular and havea mechanism for differentiating cells without altering the DNA of individual cells
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Term
| Why is rDNA useful in elucidating phylogenetic relationships at different levels? |
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Definition
Coding regions are highly conserved among species (Useful for identifying genus) and ITS regions are variable due to mutations (identifying populations)
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Term
| Is paraphyletic grouping rejected or accepted in cladistics? |
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Definition
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Term
| What is a monophyletic grouping? |
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Definition
| Group members all share a common ancestor and the group has all the descendants from that ancestor |
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Term
| What are characters that unite a clade referred to as? |
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Definition
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Term
| What are the three monophyletic domains based on molecular phylogeny? |
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Definition
| Bacteria, Archaea, Eucarya |
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Term
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Definition
| A paraphyletic group of unicellular eukaryotes |
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Term
| What causes non-endosymbiotic multi-cellularity? |
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Definition
Cell aggregation and differentiation or
Cell division and differentiation |
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Term
| Myxobacteria is a permanent aggregation of cells, true or false? |
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Definition
| False, temporary (only in stressed conditions) |
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Term
| What are some characteristics of protists? |
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Definition
Unicellular (some with multicellular stages later in life, some colonial)
Locomotion by pseudopodia, flagella, cilia) |
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Term
| The central axoneme of a cilia contains how many microtubules? |
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Definition
| 9 pairs plus a central pair |
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Term
| What is the purpose of dinoflagellates and diatoms forming long chains? |
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Definition
| Hypothesised to reduce the likelihood of being preyed upon |
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Term
| Are the protists a monophyletic group? Why? |
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Definition
| No, because their common ancestor also gave rise to the opisthokonts (which include animals), which are not included in protista |
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Term
Describe Chlamydomonas, gonium and volvox
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Definition
Chlamydomonas: Flagellated unicellular protist
Gonium: independent group of similarly oriented flagellated cells held together by cell secretions
Volvox: Interdependent flagellated cells connected by cytoplasmic bridges left over from mitosis |
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Term
| Volvox has germ cells, true or false? |
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Definition
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Term
| Describe the life cycle of volvox |
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Definition
Asexual: Germ cells mitotically divide producing daughter cells that release when the parent dies. Must invert so flagella point out
Sexual: cells differentiate into microgametes and macrogametes, fertilisation occurs and parental rupture releases zygote with hard protective shell |
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Term
| What does the Opisthokonta clade contain? |
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Definition
| Nucleariid amebas, fungi, ichthyospores, choanoflagellates, metazoa |
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Term
| What is the sister group to the metazoa? What placed them there? |
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Definition
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Term
| Describe choanoflagellates |
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Definition
Solitary or colonial aquatic protists
Similar to collar cells of sponges
Some colonies form through cell aggregation
Proteins present are homologous to those used by metazoans for cell communication and adhesion |
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Term
| Some choanoflagellates form colonies through cell division, not aggregation. True or false |
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Definition
| True, Salpingoeca rosetta |
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Term
| What are traits of a true epithelium? |
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Definition
Apical-basal polarity
Basal lamina cell junctions adhere and seal epithelium |
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Term
| What is the working definition of an animal? |
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Definition
| A multicellular eukaryotic organism that is heterotrophic and contains a blastula stage during its development |
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Term
In protostomes, the zygote undergoes spiral cleavage and the blastopore becomes the mouth. True or false?
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Definition
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Term
| Is sponge digestion intracellular or extracellular? |
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Definition
| Introcellular (lack a gut) |
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Term
| What symmetry do adult sponges have? |
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Definition
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Term
| Do sponges go through gastrulation? |
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Definition
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Term
| Which group of sponges has "true epithelium" |
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Definition
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Term
| What is the gelationous ECM called in sponges? |
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Definition
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Term
| Name cell types and their functions in porifera |
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Definition
Archaeocyte - pluripotent
Pinacocyte - form pinacoderm
spongocytes - secrete spongin
sclerocytes - secrete spicules
Collencyte - secrete collagen
Choanocyte - feeding (phagocytosis) |
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Term
| What are the incurrent vs excurrent pores of Porifera called |
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Definition
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Term
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Definition
| Pear shaped, inner membrane behind spicules, archaeocytes take up majority of centre, micropyle on top |
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Term
| Sponges are mostly hermaphrodites, true or false? |
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Definition
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Term
| What problems/solutions are associated with respiration and/or nutrition of deep cells in larger animals? |
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Definition
Lower surface area to volume ratios
1. Fold and invaginate body surface to give larger ratio
2. Develop internal transport systems |
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Term
| Asconoid spongers are larger than leuconoid sponges, true or false? |
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Definition
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Term
| Asconoid sponges are inefficient when the spongocoel is large, true or false? |
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Definition
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Term
| Which group of sponges has flagellated canals and which has flagellated chambers? |
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Definition
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Term
| Is porifera a monophyletic or paraphyletic group? Why? |
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Definition
| Paraphyletic (eumetazoa thought to be descendants of a subgroup of sponges, rather than all sponges) |
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Term
| Give the 4 major sponge lineages and their characteristics |
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Definition
Demospongiae - spicules not with 6 rays, spongin often present, all leuconoid
Hexactinellida - 6 rayed silicious spicules, multinucleated syncytial trabecular reticulum
Homoscleromorpha - skeleton absent
Calcarea - calcium carbonate spicules, true epithelia, flagellated pinacocytes |
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Term
| What is the ecological role of porifera? |
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Definition
High filtration rate (introduction of new C,N,P into coral reefs)
Bioerosion from sponges such as Cliona |
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Term
| Name some features of placozoa |
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Definition
2 species
tiny (<3mm)
Smallest amount of DNA for any animal
4 to 5 cell types
Capable of moving over a benthic substrate |
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Term
| What is a bright sphere and where can it be found? |
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Definition
| A defence organ found in placozoa |
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Term
What does placozoa encode the basic machinery for but not actually have?
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Definition
| Muscles, neurotransission, ECM and cell adhesion proteins |
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Term
| Describe the function of the upper and lower epitheloids in placozoa |
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Definition
| Upper is protective and lower is nutritive |
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Term
| Do placozoa exhibit intracellular or extracellular digestion? |
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Definition
| Both, sometimes convert ventral surface into a sac and engulf already dissolved or broken down food by pinocytosis (This is extracellular digestion) |
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Term
| What are the three scenarios of the placozoan last common ancestors feeding mode? |
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Definition
| Microphagous, macrophagous like modern placozoa, macrophageous using gut (gastrulation) which was lost in modern placozoa |
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Term
| Name the comb-jellies and describe them |
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Definition
| Ctenophores: complete gut, researchers not sure if diploblastic or triploblastic, true muscles, can incorporate cnidocytes into epidermal tissue for defense, feed on planktonic organisms |
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Term
| How can we tell where the muscles originated from in ctenophores? |
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Definition
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Term
| What are the arguments against ctenophores being triploblastic? |
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Definition
| Acoelomate and do not form a third layer that completely fills the space between endoderm and ectoderm |
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Term
| Ctenophores possess what kind of nervous system? |
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Definition
| Sub-epithelial nerve net with statocysts that coordinates beating of comb rows and balance |
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Term
| What are the two body forms in cnidaria? |
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Definition
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Term
Cnidarians undergo gastrulation, but do not form a true gut. True or false?
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Definition
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Term
| Cnidarians have bi-directional signal transfer and myelinated axons, true or false? |
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Definition
False, do not have myelination
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Term
| What is the class of cnidarians that are collectively called the corals? what are some of their features? |
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Definition
| Anthozoa: solitary or colonial, all polyps, all marine, have 1 or 2 siphonoglyphs, GV cavity separated by at least 8 mesenteries or septa bearing nematocysts |
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Term
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Definition
| Solitary or colonial, polyp (asexual) and medusa stage (sexual), velum |
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Term
| What is the entocodon in hydrozoa? |
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Definition
| Third muscular epithelium that surrounds sub-umbrellar cavity. Forms from polyp ectoderm not endoderm, hence unlikely to be homologous to mesoderm (plus it isnt embryonic) |
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Term
| What are some characteristics of scyphozoans? |
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Definition
| Large, no velum or velarium, bell margin scalloped containing rhopalium, strobilation, |
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Term
| What are some characteristics of cubozoans? |
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Definition
| Medusa dominant form, transverse section of bell is square, velarium, dioecious, internal fertilisation, rhopalia, |
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Term
| Which cnidarians exhibit bilateral symmetry and why? |
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Definition
| Many anthozoans, because of single siphonoglyph, or directional mesenteries |
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