Bio Midterm #1 (Part 3)

What is a metazoan?
Click the card to flip 👆
1 / 50
Terms in this set (50)
What is a metazoan?
Multicellular animal
Metazoans are a member of what eukaryotic clade of protists (from what lineage of protists did animals evolve)?
Choanoflagellata
Briefly describe one theory regarding the evolution of metazoans from unicellular protists. (eg. colonial flagellate hypothesis)
Colonial flagellate hypothesis: ancestor is a unicellular organism with a flagella
Why is the syncytial ciliate hypothesis unlikely?
The hypothesis is based on multinucleate ciliates, bilaterality of ciliates, and cephalization
Issues: radial symmetry of organisms like Cnidaria/Ctenophora, and no evidence of cephalization in basal metazoans
- Doesn't explain metazoan flagella
What are some of the basic characteristics of a member of the Kingdom Protoctista?
Unicellular eukaryotes
Many have cyst/spore stages
All have at least one nucleus
How does a protist differ from a protozoan?
Protists with animal cell characteristics (absence of cell wall and presence of at least one motile stage in life cycle)
All protozoans are protoctistans (protists), but not all protists are protozoans. Explain this.
Some protists are plant-like aka autotrophs whereas protozoans are animal-like and therefore, are heterotrophs
What cellular structure varies in shape in the three major groups of amoeba?
Their pseudopodia
Given an example of a member of the Phylum Euglenozoa. What are some basic characteristics of members of this phylum?
Euglena
Possess two flagella, some have chloroplasts but most are heterotrophs
To what phylum do members of the genus Plasmodium belong? What are some basic characteristics of members of this phylum?
Apicomplexa
- Unicellular and spore-forming
- Obligate endoparasites
- Have an apical complex that allow the parasites to invade host cells
To what phylum do members of the genus Paramecium belong? What are some basic characteristics of members of this phylum?Ciliata - Use cilia for locomotionDefine: symbiosis, parasitism, mutualism, commensalism.Symbiosis: interaction between two different organisms, often to the benefit of both Parasitism: symbiotic relationship in which one organism benefits at the cost of another Mutualism: relationship in which both organisms benefit Commensalism: relationship in which one organism benefits without affecting the otherBriefly describe the symbiotic relationship between a hypermastid (eg. hypermastigotes such as Trichonympha spp. or Trichomonas spp.) and its insect host.Hypermastids provide the enzyme required for its insect host to digest the cellulose in the wood that it eats - They benefit from this b/c they receive food and protection The insects benefit b/c they can digest the wood that they eatBriefly describe the life cycle of Plasmodium. What animal other than humans (and birds and reptiles) is a host for Plasmodium? How do merozoites differ from trophozoites and sporozoites (where is each found in which host)? In which host does the asexual portion of the Plasmodium lifecycle occur? In which host does the sexual portion of the Plasmodium lifecycle occur? What must be present in mosquito saliva for it to be an effective hemophagic parasite? Where in the host are microgametocytes and macrogametocytes produced? How is the "signet ring" useful in malaria diagnosis?Which species of Plasmodium is responsible for most cases of malaria? What are some symptoms of malaria? How is malaria typically treated? Can it be prevented? How? Is there an effective vaccine for malaria? Globally, where do most malaria infections tend to occur?P. falciparum, P. malariae, P. ovale, P. vivax Relapsing fever, nausea, flu-like symptoms Treated with anti-malarial medicine Prevented with mosquito nets, bug spray, anti-malarial medicine There is no effective vaccine for malaria Africa, parts of S. America, and IndiaWhich sex of mosquito bites people? What does the other mosquito sex (gender) eat?Female Anopheles mosquitoes The male mosquitoes feed on honey and nectar from flowersHow does a monoecious animal differ from a dioecious animal?A monoecious animal can be both male and female In dioecious animals, genders are separated into two different organismsDraw a generalized animal life cycle for a sexually reproducing animal from fertilization through the larval stage to the adult. You must include all of the following terms in your diagram: sperm, ovum (gametes), fertilization, cleavages, morula, blastula, gastrula, larva, adult, metamorphosis, meiosis, mitosis, cell differentiationAt what embryonic stage in animals do endoderm, ectoderm and mesoderm differentiate?After the gastrula formsList at least 5 different animals that reproduce asexually.- Hammerhead sharks in captivity - California blackworms reproduce by fragmentation (break apart to form new worms) - Hydras develop genetically identical polyps that bud off - Copperhead snakes can reproduce asexually via parthenogenesis (the polar body produced during meiosis in addition to the ovum acts as the sperm cell) - Komodo dragons in captivity (have W and Z chromosomes that multiply on their own in the egg to give rise to nonviable females or males)Why is sexual reproduction important to the process of evolution?Genetic diversityExplain at least two different ways in which sexual reproduction provides greater genetic diversity than asexual reproduction.Crossing over and recombination Bringing species from all over the world to reproduce and then bring that genetic diversity back to their regions of the worldWhat are a few different disadvantages to sexual reproduction? What are at least 2 different advantages to sexual reproduction?Disadvantages: - Have to rely on another organism of the opposite sex - Takes time/energy Advantages: - Genetic diversity - Removes bad genes from the gene poolRelative to metabolic energy cost, are sperm "cheaper" or are eggs "cheaper"?Sperm are cheaper to produceRelative to the metabolic energy cost to produce a sperm versus an egg (ovum), explain differences in the basic reproductive strategies of male versus female animals.Males seek to mate with as many females as they can to increase their chances of passing on their genes Females seek to mate with the most fit males to increase the chances of their offspring having the best possible genesList TWELVE different animal organs systems and their basic functions.Circulatory Respiratory Reproductive Digestive Nervous Endocrine Integument Lymphatic Muscular Excretory Immune SkeletalDescribe the basic function of each of the following organ systems and note any important basic differences between invertebrates and vertebrates (as reviewed in lecture):- Circulatory: delivers oxygen/nutrients to every part of the body and removes waste Reproductive: produces gametes - Digestive: processes food and absorbs nutrients - Nervous: coordinates movements and regulates responses to external/internal stimuli - Endocrine: provides communication with the rest of the body via hormones - Integument: protects our bodies from environment, heat/water regulation, form of ID - Lymphatic: filters our lymph for foreign products and transports lipids - Muscular: locomotion and support - Excretory: removes excess salt, water, and wastes - Immune: defends against microbial pathogens Skeletal: locomotion and supportDefine the following anatomical directional terms: superior, inferior, dorsal, ventral, lateral, medial, anterior, posterior, superficial, deep, cranial, caudal, proximal, distal.Superior/cranial: closer to the head Inferior/caudal: further from the head Anterior/dorsal: anterior half of the body Posterior/ventral: posterior half of the body Medial: closer to midline Lateral: further from midline Superficial: closer to the surface Deep: deeper in the body Cranial: toward the head Proximal: close to the trunk Distal: further from the trunkDraw a diagram of a reflex arc. Indicate the sensory (afferent) neurons, interneurons (association neurons) and motor (efferent neurons).What is a neuromuscular system?Includes all the muscles in the body and the nerves that innervate themHow do cnidarian nerve nets differ from nervous system seen in bilaterally symmetrical animals?Cnidarian nerve nets are arranged radially whereas bilaterally symmetrical animals have parallel nerve cords with transverse cords running the entire length of their bodiesEvolutionarily, which phylum shows the first example of an integrated neuromuscular system?CtenophoraAre there any animals in the Kingdom Animalia that lack reflex arcs?PoriferaHow does an incomplete digestive system differ from a complete one?In incomplete digestive systems, the mouth serves as the anusWhat are the basic characteristics of each of the three classes of sponges?Calcarea: calcium carbonate spicules - # of rays: 1,3,4 Hexactinellida: silica spicules - # of rays: 1,3,6 Demospongiae: much larger class than the other classes of Porifera - Silica spicules - # of rays: 1,2,3,4,5 (never 6)How do asconoid, synconoid and leuconoid sponges differ in their canal systems/body plans? What does surface area have to do with these body plans? Which body plans demonstrate the greatest and least water flow?Asconoid: most simple - Just have ostia for water to enter and central spongocoel - Limited in terms of growth b/c of water flow inefficiencies Syconoid: improves on the asconoid by invaginating body walls to increase SA of choanocytes to water passing by Leuconoid: walls are further invaginated and will form small flagellated chambersAre the basic sponge canal systems useful for determining the class for a sponge?Be able to describe the basic structure of a typical sponge using the following terms: osculum, ostia, spongocoel, prosopyle, apopyle, flagellated or radial canal, spicules, incurrent canal, excurrent canal. Be sure you can label a diagram showing these structures on a syconoid sponge.Explain how a sponge obtains nutrients based on the above.Water enters the sponge via the ostia and flows into the incurrent canal - Water flows into the prosopyl: small entrances into the flagellated chambers - Upon entering into the chamber, the water is now in a flagellated/radial canal where choanocytes can filter nutrients from the water - The water exits the flagellated chamber via the apopyle, into the excurrent canal, and out through the osculumWhat roles do each of the following cell types play in the physiology of poriferans: choanocytes, archaeocytes/ameobocytes, pinacocytes.Choanocytes: have a flagella that creates water currents to draw water into its collar - Filters nutrients out of the water Amoebocytes: deliver nutrients to the choanocytes, give rise to eggs for sexual reproduction Pinacocytes: forms the outer layer of the spongeWhich type of sponge spicules dissolve in the presence of acid such as HCl?Calcium carbonate spicules (found in Calcarea)Explain how and why gemmulation occurs in freshwater sponges.Gemmules are asexually produced clumps of food material and reproductive cells that act as spores in unfavorable conditionsExplain three different mechanisms of sponge reproduction. (what is fragmentation?)Sexual reproduction: sponges are hermaphrodites but one individual will only make one type of gamete at a time - The "male" individual will release sperm through the osculum and the "female" individual's choanocytes trap the sperm and deliver it to its egg Budding/fragmentation: portion of the sponge breaks off and regenerates into a complete organism Gemmulation: sponge releases internal buds (gemmules; aka sponge spores) that can resist harsh environments and become sponge when favorable environments arriveWhy are mutualistic symbiotic microorganisms important to many sponges?List two different kinds of animals that eat (predate) on sponges.Angelfish and hawksbill sea turtlesDraw and clearly label a simple diagram of the basic body structure of a stereotypical true jelly (scyphozoan) including basic internal anatomy.Draw and clearly label a simple diagram of the basic body structure of a stereotypical hard coral (hexacorallian) including basic internal anatomy.Draw and clearly label a simple diagram of the basic body structure of a stereotypical solitary hydrozoan (eg. Hydra) including basic internal anatomy.Draw and clearly label a simple diagram of the basic body structure of a stereotypical sea anemone (hexacorallian anemone) including basic internal anatomy.Draw a diagram to show the lifecycles of the following Cnidarians: Obelia sp., Aurelia sp. (label clearly). You must clearly label all of the following: sperm, egg (ovum), fertilization, ALL the different larval stages involved, meiosis, mitosis, blastula, adult. Be sure the feeding and reproductive structures are clearly indicated in the adult life stage.