BIOL112 EXAM TWO LABS & QUIZZES

what type of circulatory system do arthropods have?

open circulatory system with a dorsal heart

from which embryonic tissue layer is the peritoneum derived?

peritoneum is found on the innermost layer of the body wall which is the mesoderm layer

list a key ecological role performed by insects

pollination

many organisms from class Gastropoda commonly feed on algae that they scrape off of rocks using a chitonous ribbon of teeth called the....

radula

how many pairs of appendages does a chelicerate have?

six pairs

what organisms represent Gastropoda?

snails, slugs, nudibranchs

what organisms represent Cephalopoda?

squids, octopuses

name and describe the purpose of the clitellum

the clitellum secretes a viscous fluid used in sexual reproduction

what if the longitudinal muscles contracted? how would this affect the length and width of the earthworm?

the earthworm would get fatter and smaller/wider

what effect would contraction of the circular muscle layer have on the length and width of the earthworm?

the earthworm would get longer and thinner

what is the function of the swimmerets in the males?

the first two sets of swimmerets adjoining the thorax are thick and elongated, allowing the organism to form a trough-like channel used to transfer sperm to the seminal receptacles of the female

what is the name of the arthropod's largest body cavity?

the hemocoel

what is osmoregulation?

the internal balance between water and salt concentrations (maintenance of constant osmotic pressure)

what is the function of an intestine?

the intestine functions for food absorption and to get the nutrients to the rest of the organism's organs

what is the function of the swimmerets in the females?

the swimmerets hold the eggs

name one way insect/arthropod sight differs from ours

their field of view is blurrier than ours

how do arachnids feed?

they have sucking mouth parts used to suck the fluids/soft tissues from their prey, which are aided alongside fangs and a pair of pedipalps

what is the function of the towering chimneys made by colonies of termites?

they house the termites

describe what happens to the length and width of a worm segment when the longitudinal muscles contract

they make the worm shorter and wider

mollusks and many annelids have a similar stage in their development with a larval stage known as the ___________ larvae phase.

trochophore

what organisms represent Scaphopoda?

tusk shells

what anatomical feature has allowed insects to become so successful in their distribution?

wings allow insects to have access to a greater geographic area to search for food/shelter/mates and avoid predators

do arthropods have a complete digestive system?

yes

do arthropods have a coelom?

yes but it is reduced to portions of the reproductive and excretory systems

what organisms represent Bivalvia?

mussels, clams, scallops, oysters

how does segmentation play a role in the locomotion of the earthworm?

- allows the worms to move in complex ways - each segment is allowed its own muscle set which helps the worm dictate its position and its movements

how is the vision of the compound eye in insects different from our vision?

- blurrier vision - larger range of light including UV - food is color coded - process visual information more quickly

what role do setae play in the locomotion of the earthworm?

- bristles help the worm move - help the worm anchor itself to its environment

compare and contrast the level of cephalization to that of flatworms examined in Exercise 13

- cephalization in Annelids is more complex than that in flatworms because they are able to sense their environment more through sensory pits in the anterior end and through their nervous system - Annelids also have more developed cerebral ganglia

discuss why an efficient swimming method, large brain, good sense organs, and a closed circulatory system are advantages for cephalopods

- cephalopods are active predators - these advantages allow the cephalopods to hunt and attack their prey efficently

name the two specialized appendages found only in this taxonomic group.

- chelicerae (for capturing and macerating food) - pedipalps (for chewing)

discuss possible reasons for the evolution of the circulatory system in annelids. relate your answer to the body plan and size.

- circulatory system holds a strong correlation with the movement of the earthworm - increased and efficient blood flow allows the worms to pump blood to their muscles and move - the "closed" system also helps connect all of the segments together and elongates the worm's body

what are the stages of incomplete metamorphosis in dragonflies and damselflies?

- egg is submerged in water - becomes nymph - molts and grows to adult size - wings develop

name the two tagmata a chelicerate has.

- fused cephalothroax - abdomen

provide one function for the gastropod shell. explain why this is a key adaptation for the organism.

- gastropods can use their shells to retreat into when threatened - the shells are a key adaptation to the gastropods because of their unusual mode of locomotion - since snails move so slowly, they are vulnerable to attack

what types of food do most gastropods consume?

- gastropods have varied eating habits - most gastropods are herbivores that feed on plants and algae - some are carnivores

how does the exoskeleton limit the way an arthropod grows?

- hardening of the exoskeleton prevents growth expansion; thus, the arthropod undergoes molting in intervals called instars - though it temporarily exposes the organism to predation, it is necessary for the organism to grow to its full potential

what is the name of arthropod circulatory fluid?

- hemolymph is not always enclosed in vessels and is propelled by the heart in short vessels throughout the body - it is then released into the hemocoel, allowing the liquid to directly bathe the organisms' tissues and organs

what role does the coelom play in the locomotion of the earthworm?

- holds the organs and protects them from injury - acts as hydrostatic skeleton against which the muscles work

explain the difference between complete and incomplete metamorphosis.

- incomplete metamorphosis: the young is essentially a smaller version of the adult form - complete metamorphosis: young looks completely different than the adult and must go through stages that alter its appearance before reaching maturity

what are some of the key ecological roles performed by insects?

- insects carry disease, pollinate, and are natural recyclers that convert dead animals and plants into nutrients

what physiological feature has allowed insects to be successful competitors to humans and other animals?

- insects reproduce in vast numbers, both sexually and asexually - sexual reproduction results in great genetic variation, which increases the likelihood of survival and reproduction of offspring - all of this leads to adaptability that allows insects to be competitors to other animals

what do the color combinations of red and black or yellow and black represent to most animals?

- insects see red and black or black and yellow as representing poison - yellow and black also represents the danger of a sting

the crop is an adaptation which facilitates temporary food storage. why would the ability to store food be advantageous to these earthworms?

- it stores food for later so that the worm can hold off on finding/hunting for food - it also is useful for digestion because it holds the food from being digested and overworking the digestive system

open circulatory systems are relatively inefficient. why might mussels not need a more efficient system?

- mussels do not move around a lot and depend on filter-feeding - the blood in mussels is not limited by a closed circulatory system because it does not need to be circulating through the body which moves very little - cephalopods have a closed circulatory system because they are constantly moving and need constant blood circulation for muscle movement

what are the projections found in the grooves on either side of the foot of the chiton? what is the function of these projections?

- projections are the gills - gills are for gas exchange in the chiton

name two physical structures or ways the squid and octopus are similar. how are these two features helpful in their daily lives?

- squid and octopi do not have an external shell because they can swim for protection and have no need to carry around a heavy shell (helps them swim faster) - squid and octopi also both have eyes that help them locate their prey

what structure does the horseshoe crab use to exchange gases with its environment?

- the book gills on the horseshoe crab are made of leaf-like membranes and the lamellae (where gas exchange takes place) - book gills move blood in and out of the lamellae and circulate water over them

name two reasons why it is advantageous for glochidia to attach to fish swimming in streams.

- the current helps the glochidia reach its host site - helps the glochidia's survival rate because the current keeps them moving and virtually undetectable by predators

what anatomical features have limited the sizes of insects throughout their evolution?

- the exoskeleton would be too heavy to carry if the insect grew too large - insects do not have lungs to pump air over a great distance

what name is given to the aquatic larvae of dragonflies and damselflies?

nymph

some arthropods can have simple eyes that sense light and dark called...

ocelli

freshwater bivalves feed on and can reduce the abundance of photosynthetic protists and bacteria. as such, would the extinction of freshwater bivalves likely have weak or strong effects on aquatic communities? explain.

- the extinction of freshwater bivalves would have a strong effect on aquatic communities because the bivalves, the water would be full of toxins and extra nutrients that would make the water less clear and more murky - the aquatic communities would exhibit less healthy conditions for other organisms if the bivalves went extinct

what is the function of the foot in a mussel?

- the foot helps the mussel both move and anchor itself to substrates - burrowing and/or attachment via byssal threads

unlike the roundworm, whose intestinal wall is composed only of a simple epithelium, the earthworm intestine has muscles and blood vessels associated with it. what benefit do these muscles provide?

- the muscles allow the intestines to function independently of the muscular cavity of the body wall - helps prevent energy exercion - moves food and regulates speed of movement

mussels and oysters are often eaten raw. the diner cuts the adductor muscles as you did, removes the top valve, and slurps the live animal. mussels and oysters are also filter feeders. why is this meal potentially dangerous?

- the mussels and oysters could have potentially filter fed on something dangerous to humans - if eaten raw, humans could be ingesting something detriment

what is the evolutionary advantage of having a typhlosole?

- the typhlosole increases surface area and serves as the prominent in-folding of the intestine - allows for more secretion and absorption during digestion

the four major stages of complete metamorphosis in insects are?

1. egg 2. larva 3. pupa 4. adult

list two reasons for the function of the gills of the mussel

1. filter feeds 2. respiration (by sweeping water in, the water brings in oxygen

name the three main mollusk body regions found in all mollusks.

1. foot 2. mantle 3. visceral mass

water flows into the incurrent siphon, through the mantle cavity, and out the excurrent siphon. list three functions of the gills during the process.

1. gills create a current to draw water through the mantle cavity 2. gills are covered in mucus that traps small food particles 3. gills are important for gas exchange

what three body segments are common to all insects?

1. head 2. thorax 3. abdomen

list two advantages of an exoskeleton for land-dwelling arthropods

1. the exoskeleton is relatively permeable to water, allowing the arthropod to retain water 2. the exoskeleton provides protection for the organism from predators and the elements of nature

list two unique innovations that evolved in arachnids.

1. with their move to terrestrial habitats, arachnids evolved appendages that are more adapted for terrestrial locomotion 2. spiders and scorpions developed poison glands used for protection/capturing prey which compensates for arachnids' small size

approximately when did insects appear in the evolution of life on the earth?

300 mya

the tsetse fly is the carrier for what human disease?

African sleeping sickness

what is the name of the bacterium that causes Lyme disease?

Bornelia

what is the name of the arthropod vector that carries Lyme disease?

Ixodes dammini

what is metamerism?

a defining feature of annelids in which the body is divided into segments (segmentation) that are arranged linearly along the anterior-posterios axis

is a glochidium a parasite? explain why or why not.

a glochidium acts as a parasite when it attaches to the gills and fins of fish and lives off their blood

based on these limitations, what is the maximum length of insects?

about 6 inches

how does the name "trilobite" reflect the appearance of this organism?

body plan consists of 3 longitudinal lobes (2 pleural lobes surrounding the central axial lobe)

what are pheromones?

chemicals that act as messengers for increased communication

what type of skeleton does an arthropod have?

chitonous exoskeleton

what organisms represent Polyplacophora?

chitons

list one advantage of an insect undergoing complete metamorphosis.

complete metamorphosis allows different stages of the organism to specialize in their development and not compete with one another

name an anatomical feature that has limited the size of insects to 6 inches or less

exoskeleton would be too heavy

name the three regions found in their digestive system.

foregut, midgut, and hindgut

the larvae in the life cycle of freshwater mussels are called?

glochidia

arthropods have an open circulatory system, thus the fluid in the circulatory system which is called the ... is not always enclosed in the vessels

hemolymph

how have insects been vital to the survival of humans?

insects pollinate plants which is essential for the growth of fruit

name the organ responsible for osmoregulation.

malpighian tubules extract nitrogenous waste from the hemocoel and release it into the cloaca

annelids and mollusks are coelomates, with a body cavity and organs supported by peritoneal tissue derived from which embryonic tissue layer?

mesoderm

arthropods undergo changes during their development through a series of larval stages, sometimes they resemble smaller versions of the mature adult and other times they are specialized for eating and growing. this process of changes they undergo is called?

metamorphosis (incomplete/complete)