Bio Exam 3

What are two primary features that suggest a relatively early phylogenetic divergence for Sponges?

-Cellular Grade of Organization (GoO) lack embryological germ layers and adult tissue layers. -More cell individuality -can regenerate easily, a sponge can break apart and new sponges will form

What are the four clades of living arthropods?

-Chelicerata -Myriapoda -Crustacea -Hexapoda

Besides earthworms, what organisms are in Annelida? Where is much of the diversity found?

-Christmas tree worm, erratians, sedentarians. -Marine diversity, because animals are originally from the water duh.

Describe the research looking at "hookworm soup" and remember this is a nematode

-Could help with autoimmune diseases -Anti inflammatory protein

Define diploblastic. What are the two embryonic germ cell layers in diploblastic, and which tissue layers do these give rise to in Cnidaria?

-Diploblastic: having a body derived from only two embryonic cell layers -Ectoderm and endoderm -They give rise to specific adult tissues

Three genomic processes have resulted in the HOX gene differences observed between Protostomes and Deuterostomes - what are these processes?

-Duplication of genes on a single chromosome, "gene birth." -Two-fold whole genome duplication in early-diverging deuterostomes. -Some genes lose functionality because of functional redundancy, "gene death."

Arthropods are the most successful animal group - what are some reasons we can say that?

-Ecologically diverse -Numerically dominant Metazoans -Species diversity

Why are fossils and molecular clocks in disagreement over the age of animals?

-Fossil records are very much incomplete and molecular clock-technology is ever-changing. So there's a gray area of how old animals really are.

Summarize the species and ecological diversity of molluscs. What are the 3 major groups of molluscs, with examples of each?

-Gastropoda (snails and slugs) -Bivalvia (clams, mussels, scallops, and oysters) -Cephalopoda (squids, octopussy, cuttlefish)

How old is the oldest established animal fossil, and how do we know it's an animal?

-It is the Dickinsonia and is 560 mya -Shows evidence of ancient cholesterol

What is the triploblastic condition? What are the ultimate developmental fates of the three individual triploblastic germ cell layers in Bilaterians?

-It is the three embryonic cell layers, ectoderm, endoderm, and mesoderm --ectoderm: outer body covering, nervous system -endoderm: gut lining, liver, lungs -mesoderm: true muscle tissue, bone, connective tissues

When was the Cambrian explosion, and why is it of interest?

-It was 530 mya and was a major point of diversification -Fossils representing 1/2 extant animal groups suddenly appear -Increase of atmospheric oxygen. This is turn made animals have larger body sizes, develop HOX genes and the predatory ladder.

Cephalopods are intelligent animals - give three examples of such intelligence.

-Jet-propelled marine predators -Large bodies -Complex brain

Why is the chitin-based exoskeleton a key to arthropod success?

-Outer waxy layer retains water -Strong but lightweight material -varies from very hard to very flexible

Understand the general life cycle of a hydrozoan polyp, including relationships of the polyp, medusa, and larval stages. Do the same for a scyphozoan jellyfish.

-Polyps can reproduce asexually and are often colonial. -Medusas are sexual. Cycle begins as a polyp, becomes a medusa, becomes a larva and grows into a polyp.

What are the three primary cell types found in sponges, and what are their specific functions?

-Porocytes: "Ostia" cells surrounding openings -Amoebocytes: Food transport, structural support -Choanocytes: Create water currents to trap food particles; also involved in sexual reproduction

Talk about the global distribution, prevalence, and impact of Schistosomiasis in humans.

-Schistosoma trematodes are very harmful to humanity -> schistosomiasis (also called Bilharzia) -3 species in the genus Schistosoma: distributed in tropical countries worldwide -> so-called "neglected tropical disease" -causes chronic illness or liver/kidney damage (symptoms in response to egg deposition), ~20 million humans severely ill, with over 200 million people infected world wide

Where did the animal kingdom originate? Why might this be important?

-The animal kingdom originated in the ocean -Many animals remain in the ocean

What are the primary differences between Deuterostomes vs Protostomes? - remember the Table of differences.

-The position of the Nervous System -Gene duplication in HOX gene family -Fate of blastopore (first opening of future gut during embryonic development)

Why are tardigrades amazing, and what specific gene did we talk about?

-They are the most resilient animals know, can withstand extreme conditions -Protective proteins?

How do choanocytes work, and how are these cells fundamental to the sponge design?

-They create water currents and trap microscopic food particles/gametes -also involved in egg and sperm production

Describe and illustrate the complex lifecycle of a Schistosoma fluke. What is the biological significance of larval stages that use intermediate hosts?

-Trematodes (flukes): vertebrate animal endoparasites -have complex life cycles -> use vertebrate animals as primary hosts (where adults live), but also use one or more intermediate hosts -intermediate hosts -> dispersal agents for reaching new primary hosts- use of IHs requires specialized larval stages -ALL hosts have defense systems (e.g. vertebrate immune system), parasites have evolved mechanisms to overcome defenses, for multiple hosts -> parasites highly specialized for a unique lifestyle

Most (not all) molluscs share 3 primary features in common. What are these? What are possible functions of these primary features?

-Ventral muscular foot (used for movement) -"Visceral mass" that houses internal organs. -Dorsal mantle (cell layer that secretes shell

What other structures are made of chitin cuticle?

-Wings -membrane for hearing -Cuticular lenses -Structures for producing sound

What is the function of the gastrovascular cavity in Cnidarians? How does this function relate to basic cellular requirements (i.e., nutrition, respiration, etc.)?

-serves as a simple transport system for exchange of food items, gases, wastes

Schistosoma flukes have three cellular/molecular mechanisms that prevent detection by the host immune system - what are these mechanisms

-the adult schistosome tegument -> key to success, but also potential Achilles heel -Outer body wall= single syncytium (also called distal cytoplasm, DC) Evading detection by host immune system: -mask surface with host proteins -> "immune masking" -Syncytium is NOT a static layer, undergoes frequent transformation -very few parasite proteins expressed exclusively in wall of tegument (-> few targets for host immune response)

About when did arthropods invade land?

420 mya

Cephalopods have a camera-lens type eye. This type of eye is said to have evolved convergently in cephalopods and vertebrates - what does this mean??

??

What is the pH of the ocean prior to thin industrial revolution; what is it now; and what is it projected to become?

???

What is the role of cadherin?

A protein that allows cell-to-cell adhesion. (cell glue)

How are animals related to other multicellular eukaryotes?

Animals are heterotrophic eukaryotes.

What do both confirm, however? (Why are fossils and molecular clocks in disagreement over the age of animals?)

Animals be old af; on earth long af.

Remember what major group do water bears belong in?

Arthropods

What is the cuticle of arthropods and relatives made of?

Chitin

What is the closest single-celled relative of animals? What do they look like?

Choanoflagellates, who look like little (spherical body + flagellum)

A phylogeny of Cnidaria helps to explain the distribution of polyp + medusa across the major Cnidarian groups. Explain.

Cnidarians alternate between to different diploid morphologies: polyp (oral side up) and medusa stages (oral side down).

What is the function of cnidocytes and nematocysts? What is the mechanism of nematocyst discharge in Hydra cnidarians?

Cnidocytes and nematocysts are fundamental to their predatory lifestyle. Nematocysts are discharged by a force of pressure and energy (equivalent to bullet shots).

What are coral reefs? Why are coral reefs both economically & ecologically valuable - at least 3 reasons?

Coral reefs are mostly colonial anthozoans (some hydrozoans) in a symbiotic relationship with dinoflagellates. If dinoflagellates die, skeletons can't form. - Economically: fisheries, tourism - Ecologically: allow for diverse wildlife

What are the three phyla of sponges we talked about, and how do their skeletons differ? Which group contains most sponges?

Demosponges -skeletons made of collagen and spongin protein -Around 90% of all sponge species Calcarea -skeletons of calcium carbonate spicules Hexactinellid -skeletons made of fused silica spicules

What is a "body plan"?

Description of the overall system of body organization; describes symmetry (Radial symmetry, bilateral symmetry, etc.), tissue complexity, and segmentation.

What are three main innovations defining Bilateria?

Digestive, respiratory, excretory

What is the ECM and why is it important?

Extracellular Matrix hold cells together in tissues, adds structural support, act as a filter, and is involved in cell communication.

What are the Edicarean fossils?

Fossils found 560 mya that show evidence of early animal life

When we think of animals, we often think of fellow vertebrates but most animals are what?

Invertebrates

What are some well-known parasitic annelids?

Leeches

What are the "local" and "global" threats to coral reefs?

Local Threats -land based pollution, mining, "blast fishing" Global Threats -Waters are too warm -declining ocean pH (linked to increased atmospheric CO2.)

What are the two groups of myriopods and what are a couple differences?

Millipedes: -Detritivores -Each segment has two pairs of legs -has chemical defenses Centipedes: -Carnivores -Each segment has one pair of legs -Claws that paralyze prey with venom

What is the fourth major class of molluscs?

Polyplacophora (chitons)

What is the defining feature for Eumetazoan animals?

Possess true tissues derived from embryonic germ cell layers

What is a common name for nematodes, and where might we find them?

Round worms, soils and aquatic environments

In what ecdysozoans does the cuticles act as an "exoskeleton"?

Round worms?

Why is their colonial nature important p hylogenetically?

Show cellular specialization (different cell types doing different things)

What are the two keys for spider success?

Silks and venom

What morphological feature unites the clade Ecdysozoa?

Their ability to molt.

What is significant about proteins found in the choanoflagellate genome?

These proteins (cadherin) are also only found in the animal domain.

What are HOX genes, and why are they important to animals?

They are highly conserved developmental regulatory genes

Are horseshoe crabs crustaceans? Why are they of interest in biotechnology?

They are not crustaceans. Their blood forms into a gel when it detects endotoxins.

Ctenophore/comb jellies: how are they similar to jelly fish? How are they different?

They are radially symmetrical like cnidarians. They acquire their prey with their sticky threads (colloblast tentacles.)

Why are silk proteins of interest for human technology? Why can't we raise spiders for their silk like we do silkworms?

They are strong, stretchy, lightweight, biodegradable, and hypoallergenic

What do genomic analyses reveal about the origin of animals?

They have 1000s of shared genomic changes in the genome, unique to animals

Why is the shape of their cells important phylogenetically?

They often live in colonies, so they "build" to look and act like a whole.

What's so interesting about comb jellies pooping?

They're bilateral, which means they have feeding organs (mouth and booty). Jellies and cnidarians are not.

What are some important lineages within Arachnida?

Ticks, dustmite, spiders, scorpions

What are the arachnid ectoparasites that humans deal with?

Ticks, mites

What famous fossil assemblage has diverse and dominant arthropods?

Trilobites

What is the common name of Onychophora?

Velvet worms

What characteristics unite and describe animals?

We ingest food items, with tissues that develop from embryonic germ layer.

What is the common name for Annelida?

Worms

What are conotoxins? How has conotoxin diversity evolved?

a "venom cocktail" made of small peptides. Different genes = different peptides, means varying peptide functions depending on the snails.

What are some of the different ways spiders use silk?

egg sacs, nests, "balloons", burrow protection, and webs

What important symbiosis is required for reef-building corals?

photosynthetic dinoflagellates

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?

prialt, which an alter alternative to morphine. It is non-addictive and anti-tolerance treatment for severe chronic pain.

Define parasitism. Your friend tells you that parasites are lowly animals, barely evolved. You respond, "nope", parasites are actually very successful, for the following reasons .......

relationship between two species of plants or animals in which one benefits at the expense of the other, sometimes without killing the host organism.