Card Set Information
Bio 204 questions
Provide a technical definition of an animal
Multicellular heterotrophic eukaryotes that
ingest food items, with tissues that develop from embryonic germ layers
How does the animal condition differ from that
found in fungi & plants (remember that plants & fungi are also multi-cellular)?
They are mostly photoautotrophs who get energy from light or chemoherterotrophs who
get energy from organic compounds
Characterize choanoflagellates (i.e., size,
morphology) and explain why choanoflagellates are thought to be closely-related
Small aquatic with flagella
Related because they are unicellular but often
live as colonies
What are three primary apomorphies for Metazoa
1000s of shared genomic changes in the genome,
unique to animals
HOX genes (highly-conserved developmental
What are the primary molecules in and fractions
of the extracellular matrix?
Glycoproteins (protein + carbo molecules =>
proteoglycans) & collagen
What is a “body plan”
Description of the overall system of body
organization (e.g., symmetry, tissue complexity, appendages, segmentation,
What are the habitat characteristics of most
major Metazoan groups? Exceptions?
Mostly aquatic with exception in vertebrates and
About how many species of invertebrate animals
have been described? What about vertebrate animals
Only 50,000 of the known species 1.3 million
species are vertebrates
Provide a brief timeline of life on earth,
including 1.) age of earth, 2.) fossil evidence for first life, 3.) fossil
evidence for first Metazoans?
: ~ 4.6 billion YA
First fossil evidence for life
: ~3.5 million YA
Fossil evidence of first Metazoans
: ~560 MYA
What is the Cambrian Explosion? When did this
occur? Why is this event called an “explosion”?
All primary animal groups appears suddenly, lots
of diversity over a very short period of time
Provide three explanations for the Cambrian
Diversification in HOX gene cluster (major
genomic changes, causing major morphological changes)
Increased atomospheric oxygen => increased
metabolic rates, larger sizes
Escalation of predator-prey relationships
(development of more complex food-webs)
Describe, in general terms, how a molecular
clock is applies
Known divergence dates for subset of living
species (from fossil or biogeographic constraints)
Observed genetic distance from same subset of
living species (e.g., 100 nucleotide differences in 1000 bp gene= 10%
divergence) => convert this to the rate of genetic divergence per unit time
(e.g., 1% divergence per million years)
Estimate divergence dates for other living
species based on genetic divergence values only
What are the three main groups of sponges, and
how are they distinguished?
Skeletons comprised of collagen or sponging
90% of all sponges
Skeletons of calcium carbonate spicules
Hexactinellid Sponges (glass sponges)
Skeletons made of fused silica spicules
Typically live at great depths in oceans
What are two primary features that suggest a
relatively early phylogenetic divergence for Sponges?
Cellular grade of organization (GoO)- lack true
embryological germ cell layers, lack adult tissue layers (contrasts with tissue
GoO all other animals )
More cell individuality then typical cells in
remaining animals (some cells mobile, and cell differentiation is reversible)
Discuss the general characteristics of Sponges
(e.g. habitats, symmetry, lifestyle, fossil record)
~8000 described species
Fossil record to Cambrian
Lack organized body symmetry (~asymmetrical)
How are sponge bodies supported?
By a gelatinous matrix (mesohyl), supported by a
skeleton of spicules (calcium carbonate; silica) and/or protein (collagen,
What are the three primary cell types found in
sponges, and what are their specific functions?
Porocytes- cells surrounding pore (ostia)
Amoebocytes- food transport, structural support
(e.g., producing spicules)
Choanocytes (collar cells)- create water
currents and trap microscopic food particles/gametes; also involved in egg
& sperm production
How do choanocytes work, and how are these cells
fundamental to the sponge design?
They create a current which pulls water into the
sponge where it gets its nutrients and disposes of waste
Why aren’t sponges typically eaten or
over-grown? (two reasons)
Glass or calcite spicules
Production of various bio-active compounds,
often in association with symbiotic bacteria
Be able to discuss the biological properties of
the sponge molecule sceptrin
Anit-cancer, anti-fungal, anti-inflammatory
Inhibits cell mobility in various cancer cell
Define “DNA barcoding.” Why are sponges a good
candidate group for the applications of DNA barcoding?
: use of rapidly-evolving sequences
for species identification
What is the defining feature for Eumetazoan
They have true tissues, derived from embryonic
germ cell layers (EGCLs)
Define diploblastic. What are the two embryonic
germ cell layers in diploblasts, and which tissue layers do these give rise to
: have 2 EGCLs (ectoderm &
Endoderm -> gastrodermis
Define radial symmetry. Define filter-feeder.
: multiple planes resulting in
: pass food particles past a
What is the function of the gastrovascular
cavity in Cnidarians? How does this function relate to basic cellular
requirements (i.e., nutrition, respierations, etc)?
: simple transport system
for exchange of food items, gases, wastes
What is the function of cnidocytes and
For capturing prey
What is the mechanism of nematocyst discharge in
Combination of osmotic pressure (calcium ions
dumped from capsule into cytoplasm), plus energy stored in mini-collagen
proteins of capsule wall
Contrast and draw the two diploid morphological
types found in Cnidaria polyp vs. medusa
: oral side up, typically sessile, benthic
: oral side down, free-floating, pelagic
habitats (open ocean)
Discuss the colonial body organization of
A colony of physiologically-connected 2N
individuals (zoolids), derived from a single zooid by budding
What are the four major groups of Cnidaria, and
how do these groups differ in which morphological type (i.e., polyp or medusa)
is the dominant lifestage?
Both polyp and medusa stages
Polyp stage absent or reduced
Polyp stage short-lived, in most cases unknown
What are coral reefs? What are coral reefs economically
& ecologically valuable?
: some hydorzoans, mostly anthrozoans
What are the “localized” and “global” threats to
: land-based pollution (chemicals &
sedimentation), mining, “blast” fishing
: waters too warm (photosynthetic
dinoflagellates are expelled, corals “bleach”), declining pH associated with
absorption of increased CO2 (coral calcification decreases with declining pH
What are three main innovations defining
Organ systems (primary four
: digestive, respiratory,
Bilateral symmetry & cephalization
Triploblastic-> 3 EGCLs
Define bilateral symmetry and cephalization
: single plane of symmetry
divides body into mirror halves
: concentration of feeding organs,
sensory & neural structures at the anterior end of body
What is the triploblastic condition? What are
the ultimate developmental fates of the three individual triploblastic germ
cell layers in bilaterians?
: endoderm, ectoderm, mesoderm
: outer body covering, nervous system
: gut lining, liver, lungs
: true muscle tissue, bone, connective
Give examples of protostome animals and Deuterstome animals
: arthropods, mollusks, various worms,
etc. (most invertebrates)
: star fish, hemichordates,
What are the primary differences between
Deuterostomes vs. Protostomes? –remember the Table of differences
Position of nervous system
(ventral in protostomes, dorsal in deuterosomes)
Gene duplication in HOX gene family
(no duplication in protostomes, duplication of posterior HOX genes in deuterostomes)
Fate of blastopre (earliest opening of future
gut during embryonic development)
(mouth in protostomes, anus in seuterostomes)
Three genomic processes have resulted in the HOX
gene differences observed between Protostomes and Deuterstomes- what are these
Duplication of genes on a single chromosome->
resulting in “family” of related genes
Whole genome duplication (2X) in early-diverging
Some genes lose functional redundancy
Define gastrulation, blastopore, and
: invagination of endoderm to form
archenteron (future gut)
: earliest opening of future gut
: future gut
What are the primary characters supporting the
Lophotrochozoans (molecular or morphological)? What are the two morphological
features found in some, but not all Lophotrochozoans?
Some taxa with lophophore (ciliated feeding
structure), some taxa with trochophore larvae
What are the primary phylogenetic groups of
Platyhelminthes, and the lifestyles of these primary taxa?
Turbellaria- not parasites
Monogenea- fish ectoperasites
Trematoda- vertebrate endoparasites
Cestoda- animal endoparasites
Summarize the morphological features found in a
“generalized platyhelminth” (e.g., symmetry, cell layers, placement of nervous
Expected bilaterian features
symmetry, cephalized, triploblastic
Highly-branched blind, gut
Define parasitism. Your friend tells you that a
parasites are lowly animals, barely evolved. You respond, “no sir, “ parasites
are actually very successful, for the following reasons…
: benefit at expense of host
Essentially all animal groups include some
parasitic representatives, perhaps ½ of all animals species are parasites, and
basically all animals serve as hosts for one or more parasites
Discribe and illustrate the complex lifecycle of
a Schistosoma fluke. What is the biological significance of larval stages that
use intermediate hosts?
The larva uses the intermediate host as a
mechanism for reaching the new primary host
Talk about the global distribution, prevalence,
and impact of Schistosomiasis in humans.
Distributed in tropical countries around the
Causes chronic illness or liver/kidney damage
(symptoms in response to egg deposition), ~20 million humans severely ill, with
over 200 million people infected worldwide
Schistosoma flukes have three cellular/molecular
mechanisms that prevent detection by the host immune system- what are these
Mask surface with host proteins-> immune
Syncytium is not a static layer, undergoes
Very few parasite proteins expressed exclusively
in wall of tegument (few targets for host immune response)
Why is the sequencing of the Schistosoma genome
potentially important in the control of Schistosomiasis.
We can disable fluke genes that are necessary
for metabolism/survival/reproduction in human host
What is the general bodyplan of a cestode
(tapeworm)? -function of scolex & proglottids? How do tapeworms gain
nutrients without a digestive tract?
Scolex- attachment devices
Proglottids- long chaing of reproductive
No digestive tract
Symmarize the species and ecological diversity
of mollusks. What are the 3 major groups of mulluscs, with examples of each?
Gastropoda (snails, slugs)
Bivalvia (clams, mussels, scallops, oysters)
Cephalopoda (squids, octopuses, cuttlefishes,
Most (not all) mollusks share 3 primary features
in common. What are these? What are possible functions of these primary
Ventral muscular foot
: used for locomotion, as
holdfast, and feeding
: houses internal organs (primary
: cell layer that secretes shell
for protection against predation, prevents mechanical damage, prevents
dessication (when terrestrial)
Some opisthobranchs lack shells. How do they
protect themselves from the predators that abound in marine habitats?
What are conotoxins? How has conotoxin diversity
Conotoxins- bioactive peptides (small 10-40 AA
50,000-100,000 different peptides having evolved
Provide details of one example of a conotoxin
that has been developed as a drug- e.g. how does the drug work? Why is the drug
a nice alternative to morphine?
: non-addictive, anti-tolerance treatment
for severe chronic pain
Selectively blockes voltage-gated calcium
channels (propagates action potentials)
Many cephalopods, like some snail groups, have
lost their shell, how are such animals protected from predation
Fast, well camouflaged, and cryptic
Cephalopods have a camera-lens type eye.
Illustrate this condition. This type of eye is said to have evolved
convergently in cephalopods and vertebrates- what is meant by this?
: functionally very similar to
: came to the same conclusion (in this
What is primary morphological apomorphy for the
protostome group ecdysozoa? What is ecdysis?
Primary morphological apomorphy
Protein based outer body covering (cuticle)
which is periodically molted for growth
Ecdysozoans= “molting animals”
Ecdysozoan phylogenetic groups fall into 2
general categories- what are these, and how do these groups differ?
Lack appendages, mostly marine, possess internal
fluid-based skeleton (hydrostatic skeleton)
Cuticle with structural polysaccharide chitin
What are the arthropod relatives? What features
do they chare with arthropods (at least 3)?
Tardigrada “Water Bears” & Onychopora
Evolution of appendages
Cuticle with structural polysaccharide chiting
Many biologists claim that arthropods are the
most successful animal lineage. What are 3 measures of “evolutionary success”
Species diversity- 2/3 of every known animal
species is an arthropod
Ecological diversity- live in all habitats
Numerically dominant metazoans- some estimates
suggest a billion, billion individuals
What are the four main groups of living
arthropods, and the habitats in which each group can be found?
Crustacean- marine and freshwater (lobsters,
Hexapoda- terrestrial, some have secondarily
evolved back into freshwater (insects)
Chelicerata- marine and terrestrial (scorpions,
spiders, horseshoe crabs)
Myriapoda- all terrestrial (centipedes and
Outline the timeline of diversification for
arthropods, including 1) time of origin in the fossil record 2) general timing
of terrestrial invasions.
First appearance duing the Cambrian explosion
First animals to invade land ~400 MYA
What are 3 important functional characteristics
of the chitinous cuticular exoskeleton or arthropods?
Strong, lightweight material for a supportive
exoskeleton but allows mobility
Varies from very hard to very flexible (flexible
joints key to movement)
Waxy outer layer provides waterproofing (key to
Why is the arthropod exoskeleton important in
Provides support for the organism, which is not
needed in water
Provides waterproofing to prevent water loss
Chhitinois cuticle is used to build important
body structures in arthropods- give 3 examples.
Respiratory structures (tracheal system), gills
Thin cuticular membranes used to sense
vibrations & sounds
Cuticular structures used to produce sounds
What are 5 reasons for the success of insects?
Possession of wings
Important interactions with plants (pollination,
Most diverse groups (but not all insects) with
Complex sensory organs (senses of vision,
hearing, olfaction, touch all highly evolved
Insect wings are not appendages, explain. How
does this differ from the condition seen in other animals with powered flight?
Wings are not appendages (cuticular extensions
of dorsal thorax) which does not forfeit functionality of appendages
What are possible advantages of powered flight?
Colonizing new regions/habitats
Ability to effectively pollinate plants
Why are insects good pollinators? Which insect
are the most diverse pollinators? Pollination is a so-called +/+ ecological
interaction- what is benefit to insects from this interaction?
They are good pollinators because they can
easily fly from plant to plant
Most diverse pollinators (the big four):
coleopteran (beetles), hymenoptera (bees, wasps, ants), Lepidoptera
(butterflies, moths), and dipteral (true flies)
Plants receive fertilization while insects are
rewarded with nutrient-rich nectars and pollen
What does complete metamorphosis mean? What are
the lifestages of an insect with complete metamorphosis? What is a primary
ecological implication of complete metamorphosis?
: involves a major
morphological change during development (ex. Caterpillar -> butterfly)
Egg-> larva-> pupa -> adult
Promotes insect diversification
Do all insects have complete metamorphosis?
Explain this in phylogenetic terms
Two other types or metamorphosis
: immature “mini-adults” lacking
: immature “mini-adults”
What are the different types of insect
parasites? Explain why parasitism might promote insect species diversification?
Parasites for animas
Parasites for other insects
Parasites for other parasites
What are the 3 primary groups of chelicerate
arthropods, and the habitat characteristics of each group?
Horseshoe crabs (marine)
What are 3 key adaptations for predation seen in
Spider webs are made from silk proteins. Where
are these proteins produced, and what are some of the biological properties of
Abdominal glands (feet of tarantulas)
Very strong, extensible, and tough material
Why is the mass production of spider silks (for
human use) difficult? How are researchers overcoming this hurdle?
Very small amount is produced but researchers
are using other animals (ex. Goats) to produce these proteins
Spider venoms evolved in the context of what
type of prey items? What percentage of spiders are medically dangerous to
humans? What are some other potential applied beneficial uses of spider venoms?
Prey item = insects
Out of 40,000 spider species only 40 are
medically dangerous to humans
Inhibits atrial fibrillation (abnormal heart
The brown recluse causes necrotic arachnidism-
what is this? What is the range of the brown recluse in North America? What is
the nature of the medical misdiagnosis problem in western North America?
necrotic arachnidism = kills cells
brown recluse lives in eastern-central of the US
misdiagnosis comes from other diseases (ex. Lyme
disease) that causes the death of cells
There are 3 over-arching goals to research in
the Hedin lab- what are these general goals?
Seek to discover & describe new arachnid
species, and understand where these species are found (the who and where of
Conduct molecular systematic studies to
understand “how evolution works”
Use knowledge gained to inform conservation
What are the important findings for the
mygalomorph species Atypodies riversi? How do these specific findings relate to
the more general goals of the Hedin lab?
How spread out they are in California and the
different species living in different areas shows how they have spread out over
Review the primary differences between
protostomes and deuterostomes.
: no HOX gene duplication, blastopore
becomes mouth, ventral NS
: HOX gene duplication, blasstopore
becomes anus, dorsal NS
Why do echinoderms fossilize well, how old are
these fossils, and what is somewhat special about extant versus extinct
Endoskeleton helps echinoderms fossilize well
Fossils dating back to the Cambrian explosion
How do we know that echinoderms were derived
from an ancestor with bilateral symmetry? What does echinoderm phylogeny
suggest about the evolution of body symmetry in echinoderms?
Larvae of echinoderm show bilateral symmetry
suggesting secondarily evolved radial symmetry
Why do mostly radial echinoderms “break the
rules” regarding the radial/sessile expectations?
Radial animals tend to be sessile but
echinoderms are fairly active animals
What are the unique characteristics of
echinoderms found in no other animal groups?
Water vascular system connected to tube feet
Endoskeletons are not developed to the same
extent in echinoderm groups- provide 2 examples of conditions at opposite ends
of the spectrum.
Sand dollar (very hard with more calcareous
ossicles) vs sea cucumber (very soft with fewer calcareous ossicles)
Describe the water vascular system; describe how
tube feet work and their functions.
move by alternately contracting muscles that force water into the tube feet,
causing them to extend and push against the ground, then relaxing to allow the
feet to retract
feet used for
: locomotion, food capture, and respiration
Describe digestion, excretion, respiration, and
circulation in a starfish.
Digestive system is sometimes incomplete
No circulatory system
Respiration trough dermal gills and tube feet
Direst excretion (osmoconformers)
Bisexual, typically separate sexes
How do starfish differ from brittle stars?
Arms distinct from central disc which are used
directly for locomotion and not tube feet
Define asexual reproduction. Why do we call offspring formed via asexual reproduction
Single parent (no gametes)
Offspring is genetically identical to one
another and parent
What are the “pros & cons” of asexual reproduction?
Pro- allows rapid increase in numbers of
Cons- lack of genetic variation in populations
Discuss 2 main types of asexual reproduction found in invertebrate animals, with
Budding- new individuals arise as outgrowth
(bud) of parent, develops then detaches from parent (ex. Budding of medusa from
polyp in cnidarians)
Fragmentation- adult breaks into 2 or more
parts, each fragment capable of becoming a complete individual via regeneration
(ex. Planarians (platyhelminthes), and satfish (echinoderm))
Be able to illustrate a “standard” bisexual, sexually-reproducing life cycle.
Haploid gametes (fertilization)-> diploid egg
(mitosis)-> adults (meiosis)-> gametes
How are sexual gametes formed, and what is the genetic significance of this
1.) independent assortment of chromosomes 2.)
recombination during meiosis results in genetically unique gametes
Entire population of individuals are genetically
What is the evolutionary significance of meiosis?
Creates offspring that are genetically different
from parents and each other
Contrast the dioecious condition to the monoecious condition?
Monoecious- single individuals with bother M
& F sex organs
Dioecious- 2 different individuals with only one
sex organ (M or F)
How does haplodiploidy in hymenopteran insects work?
Haplodiploidy- qeen bees produce haploid eggs
with become drones but if fertilized it becomes a diploid queen or worker bee
Define external fertilization, and explain why such fertilization is expected to be
less common in terrestrial habitats?
External fertilization- haploid eggs fertilized
outside the F body
Uses water as a median for gametes to travel to
Gametes of marine invertebrates that are external fertilizers face 2 problems- what are
How do gametes find each other in the huge ocean
How do gametes recognize conspecific gametes
Define chemotaxis, and give a specific example of a chemical that causes chemotaxis.
Chemotaxis- gradient of chemicals secreted by
egg that “guides” sperm toward it
What is the acrosomal reaction, and how do species-specific proteins come into play
at this stage?
Break-down of acrosomal membrane, release of
enzymes that digest through egg jelly to egg surface
Extension of acrosomal process, with
species-specific bindin proteins recognized by species-specific egg receptor
Define internal fertilization; explain why such fertilization requires complex adult
interactions, and why internal fertilization often results in the evolution of
Internal fertilization- eggs fertilized inside F
Involved male-female courtship
Male intromittent organs used to transfer sperm
Define courtship. What are some examples of courtship in insects?
Courtship- intersexual information exchange –
via visual, chemical, and/or mechanical signaling
Be able to define and distinguish oviparous, ovoviviparous, and viviparous
Oviparous- F lays fertilized eggs into
Ovoviviparous- eggs retained in body during development,
embryos deriving nourishment from egg yolk
Viviparous- fertilized egg retained in body,
embryos deriving nourishment directly from mother
Define development. What are some major “landmarks” during animals development?
: continuous process involving
progressive changes in an individual from fertilization to maturity
Zygote subdivides determinants partitioned in
Germ layers form (gastrulation)
Body organs form, cells interact, differentiate
Distinguish spiral, determinate from radial, indeterminate cleavage. Which major clades of
animals have these corresponding types of development
Radial and indeterminate cleavage is ancestral
in bilaterians – found in all seuterostomes, some protosomes
Spiral and determinate for protostome
Define gastrulation. What are the characteristics of embryos at the end of
Gastrulation- blastomeres differentiating into
specific types of germ cells (forming embryonic germ cell layers)
At end of gastrulation, embryonic body plan in
EGCLs well developed
Body axes developed
Cells have specific positions & cell
What is the “paradox of nuclear equivalence”?
Blastomere nuclei are genetically equivalent,
but ultimately develop into very different types of cells
What are 2 main factors that influence differential gene expression during animal
development? Be able to explain these.
Cell induction (cell-cell interactions)
Serve to activate different combinations of
genes in different cells
HOX genes are important in animal evolution. As an example, know how the Ubx HOX
gene impacts wing development (and ultimately wing evolution) in flies.
HOX genes- transcription factors with 180-bp
homeobox binding domain
Different HOX genes expressedin different cells
of developing embryo, regulate the expression (+/-) of many other genes
(developmental regulatory genes)
Ubx expressed in third thoracic segment (T3) of
flies, represses expression of a gene which generates wing tissue
What are the basic requirements of all animal cells?
Input- sugars, amino acids, oxygen
Output- carbon dioxide, nitrogenous wastes
Maintain- water, salt balance
How does surface area to volume ratio vary with cell size? Why are animals made up
of many small cells, versus fewer, large cells?
The larger a cell the smaller the surface to
The smaller the cells the larger surface area to
volume they occupy, large SV ratio necessary for effective materials transport
(input & output)
3 primary factors interact to influence how animals get materials to and from all
cells in the body- what are these?
Body organization (cell layer complexity ) ->
Environment (aquatic vs. terrestrial)
How do sponges get materials to cells? What about Cnidaria (examples of a
diploblastic animal)? Platyhelminthes?
Sponges are aquatic with porous bodyplan which
allows water to flow thru body
Cnidarians- aquatic with GV cavity sometimes
greatly subdivided (ex. Extends into tesntacles) all cells of body in contact
with GV fluids or external fluid medium
Platyhelminthes- branched gut in aquatic or
moist terrestrial habitats
What are the constraints of the Sponge/cnidaria “materials exchange” design?
Must be aquatic, or if terrestrial restricted to
No party of the body can be more than few cell
Limited “complexity” with these solutions
What is internalization?
Internalization- cells exist in internal
environments that is different from external environment
What are the 4 major organ systems that most bilaterians possess, and the functions
of these systems?
Digestive system- food, salts, water in
Respiratory system- oxygen in, carbon dioxide
Excretory system- nitrogenous wastes out,
maintains salt & water balance
Circulatory system- transport system
Provide an example of an animal with absorptive nutrition. How does such an animal gain
Cestodes (platyhelminthes)- lack digestive
Absorb organic molecules digested by host
What are the 3 main modes of ingestive feeding in animals?
What does it mean to feed on particulate matter, what are the 2 primary ways of such
feeding? What is plankton?
Particulates- (microscopic organinc “stuff”)
suspended in water column
Suspension feeders and deposit feeders
Suspension feeders use several means to feed- provide an invertebrate animal example.
Provide an invertebrate animal example for a deposit feeder.
Suspension- marine annelids (use of flagella or
cilia to produce current), barnacles (sweep feeing organ), foragers
Deposit- marine polychaetes (pass sediment
through body removing nutrients)
What are 4 categories of animal “macroscopic feeders”?
Detritivores- eat “dead stuff” (and feces)
Why are detritivores ecologically important on land? What are 3 “services” provided
by dung beetles that are valuable in the cattle industry?
Break down detritus
Free up chemicals & minderals for future use
Help in soil formation
Invertebrate animals have evolved many special adaptations for predation- provide 2 specific
Sticky aerial nets- spider webs
Venoms- for stunning, paralyzing, killing prey
Traps- antlion larvae
Bilaterian digestive systems are regionally-specialized- what are 2 different process that
occur in different regions of the alimentary canal?
Mechanical digestion (crushing food, chewing)
Extravellular chemical digestion
What are the specific functions of animal circulatory (= transport) systems? What
are the 3 major types of circulatory systems seen in animals?
: to transport respiratory gases,
nutrients, excretory products, hormones to/from interstitial fluids
Lacking (ex. Sponges, cnidarians,
platyhelminthes) cells in approximate contact w/ external medium, GV cavity, or
“closed” circulatory system
Some animals (including some triploblasts) actually lack a circulatory system – give
an example. How is “materials exchange” accomplished in such an animal?
Ex. Sponges, cnidarians, playhelminthes
Material exchange from GV cavity or directly
into external medium
How does a “closed” circulatory system differ from an “open” circulatory system?
Which system provides more efficient blood flow?
Closed- blood plasma circulates in narrow vessels
& ultimately to capillaries propelled by heart (blood plasma remains
largely separate from interstitial fluid)
Open- no distinction between blodd &
interstitial fluids (together called hemolymph)
Define external respiration. What are 2 primary characteristic of all metazoan
Exchange of oxygen/carbon dioxide between whole
organism & environment
Respiratory surfaces characterized by large
Respiratory surfaces are moist (respiratory
gases must diffuse across aqueous boundary)
How does aerial breathing differ from aquatic breathing?
More oxygen molecules in air (20-40 X more)
Oxygen molecules diffuse about 10,000 times more
rapidly in air than in water
Aquatic breathers must be efficient at removing
oxygen from water, expend more energy doing so
What are the 4 different types of animal respiratory systems discussed in class? Be
able to discuss how these work, and give specific animal examples for each.
Cutaneous respiration- gas exchange by direct
diffusion across body surface
Ex. Flatworms, earthworms, other very small
Only works in aquatic or moist terrestrial
Often used in combination with other types of
Gills- thin walled extensions (evaginations) of
the surface of aquatic animals
Typically highly branched or folded (increases
Gills either external (facilitates ventilation)
or internal (greater protection)
Lungs- internal air filled sacs with large
surface areas, often ventilates
Evolved for respiration on land-> lung
internalization related to water conservation in terrestrial habitats
Tracheal systems- air filled cuticular tubes
that branch throughout body of terrestrial arthropods (ex. Insects and some
Largely supplants gas transport role or
Why is lung internalization so important?
Water conservation for terrestrial living
What are 2 primary functions of excretory systems?
Maintain salt & water balance (~constant
Rid cells & body of toxic nitrogenous wastes
resulting from cellular metabloism
Define osmosis. Why does osmosis affect the salt and water balance of intracellular
: passive diffusion of water molecules
across selectively permeable membrane in response to differing solute
Be able to distinguish the different osmolarities of extracellular fluid
enviornments (i.e., hypotonic, isotonic, hypertonic).
Hypotonic- relatively low solute outside (water
enters cell = cell burst)
Isotonic- equal solute concentration inside
Hypertonic- relatively high solute outside
(water leaves cell = cell shrivel)
How do excretory systems control the osmolarity of extracellular fluids?
Filtering interstitial fluids
Active secretion and resorption of specific ions
What does it mean to say that most marine invertebrates are osmoconformers?
Osmoconformers- osmolarity of interstitial
fluids match that of external aquatic environment
When we talked about invertebrate animals, we discussed several “useful
biomolecules” (i.e. molecules with potential positive impacts on human
well-being)/ provide 2 examples of such molecules.
Sceotrin- (marine natural compound in sponges)
inhibits cell motility in a variety of cancer cell lines
Prialt- (comes from slugs) primary alternative
to morphines is non-addictive & anti-tolerant
Why is species “value” best considered “unpredictable”?
Because no one can guess what we may discover
from and organism and the beifits they may hold for us
Ex. Patent of stable DNA polymerase from
thermophilic bacterium is now wothr $200 million per year
What are current and projected levels of species extinction?
Currently 1,000 times the avg and expected to
raise to 10,000
What are the 5 primary causes of species extinction?
Invasive species & diseases
How large is the human population currently (approximately)? Predicted size in the
Currently- ~7 billion
2050- 10-12 billion
Define “ecological footprint”.
Amount of land/shallow sea needed for food,
water, housing, energy, transportation, commerce (measure of how consumptive