Log in to StudySoup
Get Full Access to UA - COGS 182 - Study Guide
Join StudySoup for FREE
Get Full Access to UA - COGS 182 - Study Guide

Already have an account? Login here
Reset your password

UA / Science / COGS 182 / What is Nematocysts?

What is Nematocysts?

What is Nematocysts?


School: University of Arizona
Department: Science
Course: Introductory Biology II
Professor: Hunter bonine
Term: Spring 2016
Cost: 50
Name: Midterm 2 Study guide
Description: Covers material from 4 lectures: Diversity of Animals 2, Diversity of Animals 3, Bacterial Symbionts of Animals, and Animal Form, Function and Physiology
Uploaded: 02/26/2016
14 Pages 5 Views 8 Unlocks

Herta Haley (Rating: )

Same time next week teach? Can't wait for next weeks notes!


What is Nematocysts?

Diversity of Animals 2: Protostomes (other than Arthropods)

I. Cnidarians – hydras, jellies, sea anemones, corals

a. Basic body form

i. two basic body forms: polyp and medusa

ii. a sedentary and mobile form  

b. key adaptations  

i. Nematocysts: stinging threads that function like miniature harpoons. Used for:  1. capturing prey

2. defense against predators

3. defending territories  

4. Corals secrete calcium carbonate

c. feeding niches

i. carnivores that use their tentacles to capture small animals and protists and to  push the prey into their mouths

ii. corals: shallow, clear, nutrient-poor water

d. reproduction

i. asexual reproduction – budding off from polyps  

II. Lophotrochozoa (the Platyhelminthes)

a. basic body form

i. grow incrementally by adding to their skeletal elements

What is the basic body form of Lophotrochozoa (the Platyhelminthes)?

ii. Platyhelminthes – no coelom  

iii. in most, mouth but no anus Don't forget about the age old question of mat 231

iv. lack circulatory, respiratory system, absorb O2 through body wall

v. slow movement  

vi. bilaterally symmetrical, incomplete digestive tract (a gastrovascular cavity) b. feeding niches

i. some free-living; many parasites

ii. Ex: Schistosoma – cause disease called Schistosomiasis

c. reproduction

i. some asexual

ii. sexual, most hermaphrodites – two hermaphrodites lie next to each other, each  donates sperm to the other’s egg

III. Annelida – segmented worms  

a. basic body form

i. head with brain – more sophisticated nervous system  

ii. coelom We also discuss several other topics like What causes doppler effect?

iii. segmentation of body and coelom

iv. respiration across body wall

b. feeding niches

i. feeding varied

What is the basic body form of Annelida – segmented worms?

Don't forget about the age old question of managerial accounting notes

ii. Earthworms eat organic material in soil


iii. Marine polychaete worms are filter feeders/parasites/predators

iv. leech – blood  

c. reproduction

i. usually sexual reproduction  

IV. Mollusca

a. key adaptations

i. bright colors – sign of toxicity

ii. defend themselves with nematocysts  

iii. mantle – sheet of skin

1. secretes shell, forms gills for gas exchange, and in cephalopods forms  

muscular cavity that forcibly ejects water for locomotion

iv. radula – hardened tongue  

b. feeding niches

i. mostly grazers (ex: snails on algae)

ii. or predators (cephalopods)

c. reproduction – sexual  

V. Nematoda

a. feeding niches

i. many free living decomposers and parasites of almost everything  

b. reproduction

i. sexual – some species have both sexes, some are hermaphrodites

VI. Definitions

a. Nematocyst – specialized cnidae that are characteristic of jellies and other cnidarians. it  is an explosive cell containing one giant secretory organelle; used for prey capture and  defense from predators  

b. Chromatophores – pigment-containing and light-reflecting cells, or groups of cells,  found in a wide range of amphibians, fish, reptiles, crustaceans, and cephalopods.  c. Medusa- one of two types of cnidarian body forms; an umbrella-like body form; also  called a jellyfish

d. Polyp – one of two types of cnidarian body forms; a columnar, hydra-like body e. Plankton – a diverse group of organisms that live in the water column of large bodies of  water and cannot swim against a current. They provide a crucial source of food to many  large aquatic organisms, such as fish and whales.  We also discuss several other topics like mat 1010
We also discuss several other topics like ucsb as

f. Radula – used by mollusks for feeding, sometimes compared to a tongue. It is a  minutely toothed, chitinous ribbon which is typically used for scaring or cutting food  before the food enters the esophagus.  

g. Nudibranchs – brightly colored a marine gastropod mollusk that sheds its shell after the  larval stage. Uses nematocysts as defense mechanism.  

h. Cephalopods – a member of a group of mollusks that includes squids and octopuses.  i. Schistosoma and Schistosomiasis – see above


j. Trichinella and trichinosis – a round worm parasite of mammals including rodents, pigs,  and humans; pigs get infected by eating uncooked meat

k. intermediate host – a host that harbors the parasite only for a short transition period,  during which (usually) some developmental stage is completed

l. definitive host – a host in which the parasite reaches maturity and, if possible,  reproduces sexually  

m. medicinal leeches – bloodletting popular for centuries; fell out of favor in mid 1800s VII. Practice Questions:

a. The fully lined cavity between your outer body wall and your digestive tract is an  example of a  

i. coelom

Diversity of Animals 3: Arthropods and Deuterostomes

I. 4 Subphyla

a. Chelicerata

b. Crustacea – dominant marine arthropods  We also discuss several other topics like r/uofm

c. Myriapoda

d. Hexapoda

II. Why are there limits to arthropod size?

III. Why have insects been so evolutionary successful?

i. the ability to fly has been a major factor in their success

IV. Key morphological characters of Echinodermata, Chordata?

a. Echinodermata

i. Ex: sea stars, sand dollars, and sea urchins

ii. lack body segments, most are radially symmetrical as adults  

iii. not closely related to cnidarians or other animals that never show bilateral  symmetry

iv. have endoskeleton – a hard internal skeleton

v. have a water vascular system  

b. Chordata

i. Dorsal, hollow nerve cord

ii. notochord – a flexible, supportive, longitudinal rod located between the  digestive tract and the nerve cord

iii. pharyngeal slits - gill structures in the pharynx, the region of the digestive tub e  just behind the mouth

iv. a muscular, post-anal tail (a tail posterior to the anus)

V. Distinguish lineages of vertebrates

a. Three linages of fishes

i. Jawless fishes

ii. Cartilaginous fishes – have a flexible skeleton made of cartilage.


iii. Ray-fin fishes- most bony fishes, including tuna, bass, perch, and the rainbow  trout are ray-finned fishes. Their fins are supported by thin, flexible skeletal  rays.  

b. Terrestrial vertebrates

i. amphibians

ii. reptiles (including birds) and mammals

VI. What habitat would you expect to see amphibians in?

a. Can be on land or in water but are most likely in water because their eggs would dry out  in land.  

VII. 3 types of mammals:

a. Monotremes – the egg-laying mammals.

i. Ex: duck-billed platypus.  

b. Marsupials – have a brief gestation and give birth to tiny, embryonic offspring that  complete development while attached to the mother’s nipples. The nursing young are  usually housed in an external pouch, called a marsupium.  

i. Kangaroo and her joey

c. Eutherian mammals – commonly called placentals because their placentas provide  more intimate and long-lasting association between the mother and her developing  young than do marsupial placentas. Make up about 95% of the 4500 species of living  mammals.  

VIII. Definitions

a. Pentaradial symmetry – only exhibited by phylum Echinodermata; ex: sea stars, sea  urchins, sea lilies, sand dollars, and sea cucumbers  

b. osmoregulation – the active regulation of the osmotic pressure of an organism’s body;  meaning fluids maintain the homeostasis of the organism’s water content

c. estuary – a partly enclosed coastal body of brackish water with one or more rivers or  streams flowing into it, and with a free connection to the open sea.  

d. Complete metamorphosis – larval stages are specialized for eating and growing and  look very different from the adults, which are specialized for dispersal and reproduction.  Metamorphosis from the larval stage to the adult occurs during a pupal stage.  i. Ex: caterpillars, which are larvae of moths and butterflies

e. notochord – a flexible, supportive, longitudinal rod located between the digestive tract  and the nerve cord; found in animals in phylum Chordata  

f. Swim bladder – a gas-filled sac; evolved from balloon-like lungs, which the ancestral  bony fishes may have used to supplement their gas exchange by gills in shallow water.  g. dorsal hollow nerve cord – present in chordates; dorsal means “back” side, as opposed  to front of an organism;  

IX. Practice Questions

a. Contrast the skeleton of an echinoderm with that of an arthropod.

i. an echinoderm has an endoskeleton, an arthropod has an exoskeleton

b. Most of Earth’s species of living organisms are…


i. insects

c. The phylum Arthropoda is named for its members’  

i. jointed appendages  

Bacterial Symbionts of Animals

I. Symbiosis

a. Intimate association between unrelated organisms

b. Includes parasitic (harmful), mutualistic (beneficial) relationships, and ones that are  difficult to categorize

c. A symbiont is a smaller organism that lives in or on the larger one.  

d. Microbial symbionts are everywhere (not just in animals), and not just bacteria e. Not all bacteria are germs; skin bacteria protect against infection

II. Why are we only learning this now?

a. Less than 1% of bacteria can be cultured

b. Many bacteria look similar, even when using electron microscopes

c. We have a limited ability to investigate complex communities of bacteria with just  morphology.

III. Review

a. Polymerase chain reaction (PCR) - makes lots of DNA out of a very small amount.  i. Short segments of DNA (primers) bind to genes of interest at each end. Then:  heating and cooling, a DNA polymerase, and free nucleotides, causes  

exponential increase in number of copies.  

1. What’s the value of making lots of DNA out of a very small amount?

a. makes it easier to study

ii. DNA sequencing - new techniques relatively inexpensive, makes sequencing a  single bacterial gene from thousands of cells affordable.  

1. What advantage does DNA sequencing have in helping us characterize  

the diversity of bacteria?

2. Critical technique that changed our ability to understand the  

mammalian gut flora (the bacteria in the gut)

iii. The axenic (NO gut microbes) and gnotobiotic (reduced and known number of  microbial species) mouse models.  

1. Why do you think this might have been an important breakthrough?

a. You can start looking at responses to individual components to  

give you an idea of what these things do and how they function

iv. A critical effort to characterize all of the bacteria associated with humans: The  Human Microbiome Project

1. Sequenced a single bacterial ribosomal gene

IV. Bacteria ON animals

a. Human Skin Bacteria

i. Found about 1000 species of bacteria, a trillion cells, most non-pathogenic


ii. Amazing variation in the communities, e.g. compare “manubrium” (high chest)  with front and forearm - completely different bacteria

iii. What do they do?

1. Bacteria and sweat cause acid environment that makes it more difficult  for pathogenic bacteria to establish

2. May secrete antimicrobial substances that keep pathogenic bacteria  

from dominating

3. A common theme: pathogens common in/on healthy individuals, not  

just causing disease

4. Ex: Bacteria on beewolves

a. Capture bees; nest in sandy soil, put paralyzed bee in burrow -

larvae feed on bees. When larval beewolves complete  

development, they spin cocoon, overwinter. Nest is moist: risk  

of bacterial or fungal infection

b. Beewolves carry bacteria on their antennae

i. Actinobacteria

ii. Transmitted from mother to offspring

iii. secreted in burrow by mother, incorporated into  

cocoon by larvae

iv. each species of beewolf has its own species of  


v. Bacteria live in pockets in antenna, fed by wasp  


c. What do you think the bacterium role is? How would you test  

this idea?

i. You’re more likely to have successful offspring if you  

ii. remove actinobacteria so that bacteria can grow and  

potentially kill of larvae

V. Bacteria in animal cells

a. Not just in bacteria but lots of viruses, some protists are parasitic symbionts ( =  pathogens) of human cells

b. Bacterial cell pathogens are less dangerous now than they were - why?

c. The bacterium Rickettsia prowazekii is carried by human lice, and causes typhus. d. Typhus

i. very high fever, potentially leading to death

ii. epidemics often followed wars and natural disasters where lice density was  high

iii. During WWI typhus caused 3 million deaths

iv. thousands of inmates in Nazi concentration died of typhus  

v. Can be effectively treated with antibiotics.


e. They are vertically transmitted (parent-offspring), not horizontally or contagiously, like  a cold, or most diseases we can think of  

i. Can we guess anything about the relationship between insect and bacteria from  knowing how the bacteria are transmitted?

f. Many of these interactions are beneficial for both partners (mutualism)

i. Aphids - plant sap sucking insects - live on a diet that’s mostly sugar water with  low levels of amino acids many not the kind they need to make proteins

ii. They house bacteria in special organ - bacteria synthesize essential amino acids iii. Aphids without bacteria cannot reproduce  

iv. Aphids and bacteria have evolved together

VI. Bacteria in guts

a. In “mice and men”

i. Historical (and quite recent) characterization of gut bacteria as “commensal”  (i.e. beneficial to bacteria)  

b. In humans

i. What’s in there?

ii. About 1000 species, 100 trill cells

iii. we may carry more bacterial cells than human cells

iv. about 2-5 pounds of our weight

c. Where do they come from?

i. Birth canal - a few species

ii. Mother’s milk - 600 species; in first few years, more and more bacteria are  acquired

d. In humans, what do they do?

i. Make vitamins, digest complex starches

ii. Help the gut develop normally

iii. Help the immune system develop normally

iv. Keep pathogens from making us sick.  

v. Many more claims, including roles in autism, reducing stress, etc.

e. Communities of bacteria differ:

i. an environmental component (some similarity within a household)

ii. genetic component (identical twins bacteria more similar than fraternal twins) iii. Differences in bacterial communities between obese and thin people

iv. Obese people have more bacteria from the phylum Firmicutes, fewer  


v. Thin people had the reverse, and a more diverse set  

vi. Obese people who became thin acquired a ‘thin person’s bacterial community’ vii. Nutrition differs depending on what bacteria one has

viii. Ex: study performed in Malawi in 317 pairs of twins  

1. Of the pairs of twins:

a. 43%


b. In cases where twin differed, the gut flora (= community of gut  

bacteria) also differed

2. Does this show the gut flora is responsible?

ix. Critical experiment - mice with gut flora from malnourished children lacked the  ability to make some vitamins and digest complex carbohydrates.  

x. Ex: when Jason and Jonah compete in this Twinkie eating contest...They may eat  the same number of Twinkies but get different numbers of calories from hem f. Questions

i. What is the role of bacteria in determining obesity

ii. What kind of data are the kinds we’ve heard about so far?

g. Correlative data may not differentiate between cause and effect.  i. Does the gut flora in an obese person CAUSE obesity? (causal explanation)? Or  does obesity (the different physiological state of an obese person) AFFECT the  type of bacteria that thrive in an obese person?

ii. What kind of experiment would you like to do?

1. one that has a control, manipulated variable, etc

iii. Study:  

1. Collected microbes from guts of human twins, in each case one lean,  one obese

2. Inserted collection of microbes from each twin into axenic mice

3. First result: mice that received flor from obese twin gained weight, ones  that received lean twin flora didn’t even though ate similar amounts

4. Then wondered - what if mice are in the same environment?

5. The ‘lean’ bacteria did not transfer or prevent weight gain when mice  were fed a high fat, low fiber diet (e.g. pelleted pizza and sweet  

breakfast cereal). But did when the diet was low in saturated fat, high in  fruits and vegetables.

iv. So should you get a thin roommate to stay thin?

1. May need a thin housemate who also eats well.

v. What can we conclude from this study?

1. Does the study suggest a direct role of the gut flora on tendency to gain  weight?

2. What role might diet play?

3. How much can we extrapolate from mice to people?

h. Role of gut bacteria in development

i. the gut lining (epithelium) does not develop correctly in axenic mice ii. among other things, the bacteria influence the number of microvilli, and the  intestine's capacity to absorb nutrients

iii. Early exposure to microbes may be necessary for calibrating the immune  response to microbes


iv. Desired immune response - activate for pathogens, not against oneself or  harmless bacteria  

v. Axenic mice produce abnormally high numbers of killer T cells - caused  


vi. As adults, more likely to have asthma and inflammatory bowel disease  

vii. The woman who almost died:

1. Likely contracted a pathogenic bacterial infection, Clostridium difficile,  

in hospital stay Clostridium infections linked with overuse of certain  

antibiotics, 3 million people infected in US/year.  

2. Had ongoing diarrhea, cramps, and vomiting for a year - antibiotic  

treatment didn’t help (and helps only 15-25% of patients generally)

a. Why might they not have worked?

i. developed resistance  

3. Eventually got a fecal transplant from her husband - tube went down  

her nose, past the stomach and into the small intestine

4. Cured within 24 hours

5. Feces: about 50% bacteria

6. was initially the cure of last resort

viii. Recent clinical trial

1. patients with C. difficile infections

2. 16 received bowel lavage + fecal transplant, 13 received bowel lavage +  

antibiotics, and 13 received antibiotics alone

Animal Form, Function, and Physiology

I. Introduction

A. Animal structure is fundamentally related to function

B. Animals are generally studied through their anatomy and physiology

1. Anatomy - the study of an organism’s physical structure

2. Physiology - the study of how the physical structures in an organism function C. Both are diverse!

II. Anatomy

A. Definition: Physical structure (aka form) of an organism/and or its components III. Physiology

A. refers to “nature, origin”, “knowledge”

B. Definition: study of the mechanical, physical, and biochemical functions of living  organisms.  

IV. Tissues, Organs, and Systems  

A. If a structure found in an animal is adaptive

1. The structure’s size, shape, or composition will correlate w/ its function

2. Ex: beak size and shape in ground finches on the Galapagos Islands

B. If a mutant allele alters the size and shape of a structure to make function more efficient


1. Individuals with that allele produce more offspring

2. Allele will increase in frequency over time

V. Structure and Function at Cellular and Molecular Levels

A. Correlations between form and function begin at the molecular level

1. Ex: protein shape correlates with protein role as enzymes, structural  

components of the cell, or transporters

B. Similar function between structure and function occur at the cellular level 1. Ex: cells that secrete digestive enzymes contain a lot of rough ER and Golgi  bodies

C. Likewise, cell shape and function correlate  

1. Absorptive cells have a large surface area.  

VI. Tissues are Groups of Cells that Function as a Unit

A. Animals are multicellular - their bodies contain distinct types of cells that are specialized for different functions.  

B. A tissue is a group of similar cells that function as a unit

1. Embryonic tissues give rise to four adult tissue types

a) Connective

b) Nervous

c) Muscle

d) Epithelial

C. Connective Tissue

1. Consists of cells loosely arranged in a liquid, jellylike, or solid matrix.  

2. Matrix comprises extracellular fibers and other materials

3. Is secreted by the connective tissue cells themselves

4. The nature of the matrix determines the nature of the connective tissue

5. Loose connective tissue - contains an array of fibrous proteins in a soft matrix a) Examples include adipose and fat tissue

6. Dense connective tissue - found in the tendons and ligaments; connects  

muscles, bones, and organs

7. Supporting connective tissue - has a firm extracellular matrix; includes bone  and cartilage

8. Fluid connective tissue - cells surrounded by a liquid extracellular matrix

a) Ex: blood contains various cell types and has a specialized extracellular  

matrix called plasma

D. Nervous Tissue  

1. Nervous tissue consists of nerve cells, or neurons, and several types of  

supporting cells

2. Most neurons have two distinct types of projections from the cell body, where  the nucleus is located

a) Short, branching dendrites, which transfer electrical signals from other  

cells to the cell body


b) Long axons, which carry electrical signals from the cell body to other  cells

E. Muscle Tissue

1. A key innovation in the evolution of animals - like nervous tissue, it appears in  no other lineage

a) Functions in movement

2. Three types: 

a) Skeletal muscle

b) Cardiac muscle

c) smooth muscle

F. Epithelial Tissue

1. Epithelial tissues (epithelia) are tissues that cover the outside of the body, line  the surfaces of organs, and form glands

2. An organ is a structure that serves a specialized function and consists of several  tissues.  

3. A gland is a group of cells that secrete specific molecules or solutions 4. Epithelia carry out several functions

a) Protection

b) Transport of water and nutrients  

5. Epithelial cells typically form layers of closely packed cells  

6. All epithelial tissue has a polarity

a) The apical side faces away from other tissues

b) The basolateral side faces the animal’s interior

(1) The basal lamina connects the epithelial to the connective  


c) The apical and basolateral sides of an epithelium have distinct  

structures and functions  

G. Functions of Apical and Basolateral Epithelia

1. The apical side of an epithelium generally lines organs and secretes mucus.  a) An example of this is the lining of the esophagus

b) Cells are actively undergoing mitosis

2. Basolateral side links the apical to the basal lamina

H. Organs and Organ Systems

1. Cells with similar functions are organized into tissues

2. tissues are organized into structures called organs

3. organs are part of organ systems which consist of groups of tissues and organs  that work together to perform one or more functions  

I. Form, Function, and Adaptation

1. Biologists who study animal anatomy and physiology are studying adaptations 2. Heritable traits allow individuals to survive and reproduce in a certain  environment better than individuals that lack those traits


3. Adaptation results from evolution by natural selection  

VII. The Role of Fitness Trade-Offs

A. Trade Offs - inescapable compromises between traits

1. Ex: quality and quantity of offspring

B. Researchers investigated the predicted trade-off between egg size and egg number  (clutch size) by manipulating these parameters in crickets

1. mating in crickets involves a behavioral adaptation

2. their results showed that such trade-offs do exist

VIII. Adaptation and Acclimation

A. Adaptation is a genetic change that occurs over generations in response to natural  selection in a population

B. Acclimatization, or acclimation

1. A phenotypic change that occurs in an individual

2. In response to a short-term change in environmental conditions

3. Acclimation often is applied to change that take place in the laboratory setting  C. Allometry  

1. Which animal was bigger in real life?

2. Isometry (1:1) is rare

D. What are effects of changing body size among species? How does SA/V ratio change as  we consider larger and larger species?

1. How do things change with body size?  

a) Allometry

E. Surface Area/Volume Relationships: Theory

1. The cell surface area determines the rate at which gases and nutrients diffuse  across the membrane

2. The cell volume determines the rate of diffusion

a) As a cell gets larger, its volume increases much faster than its surface  

area does

b) The physiological activity can be measured as the metabolic rate  

3. Volume increases faster than surface area as animals become longer (bigger) 4. Metabolic rate - the rate at which oxygen and energy are consumed

a) Often measured as oxygen consumption per unit time

b) The consumption of energy is measured as the basal metabolic rate  


c) BMR is the rate at which an animal consumes oxygen while at rest with  

an empty stomach, under normal temperature and moisture conditions

d) The BMR is measured in mL of O2 consumed per gram of body mass per  


F. Comparing Mice and Elephants

1. Small animals have higher BMRs than do large animals


a) Ex: an elephant has more mass than a mouse, but a gram of elephant  

tissue consumes much less energy than a gram of mouse tissue does

2. As an organism’s size increases, its mass-specific metabolic rate must decrease a) Or the surface area available for exchange of materials would fail to  

keep up with the metabolic demands of the organism  

3. Per-gram metabolic rate is LOWER if animal is larger.  

IX. How Do Animals Regulate Body Temperature?

A. Heat exchange is critical in animal physiology  

1. overheating can cause proteins to denature

2. protein denature can lead to dehydration  

3. low body temperatures can slow down enzyme function and energy production B. Mechanisms of Heat Exchange  

1. All animals exchange heat with their environment in four ways:

a) Conduction (solid-solid)

b) Convection (solid-liquid/gas)

c) Radiation (no direct contact)

d) Evaporation (phase change)

C. Variation in Thermoregulation

1. There is also a continuum regarding whether animals hold their body  

temperature constant

2. Homeotherms keep their body temperature constant

3. Heterotherms can tolerate changes in body temp

4. Many animals lie somewhere in between these two extremes  

D. Chemical and biological reactions tend to happen faster at higher temperatures. E. Q10 effect; how much does metabolic rate change with 10C change in temperature? 1. Q10 typically between 2 and 3

X. Variation in Thermoregulation

A. Many animals can control their body temperature through process of thermoregulation,  including

1. obtaining heat

2. holding body temperature constant

B. An endotherm produces adequate heat to warm its own tissue

C. an ecotherm relies on heat gained from the environment

D. humans are endothermic homeotherms

XI. How do endotherms and ectotherms differ with respect to metabolic rate? A. Higher for endotherms because they rely on their own energy reserves for  thermoregulation.


Page Expired
It looks like your free minutes have expired! Lucky for you we have all the content you need, just sign up here