Bio Diversity Exam 3 (chpt 34)

incomplete digestive system

only one opening

sponges, cnidarians, flatworms

complete digestive system

has separate mouth and anus

nematodes, earthworms, vertebrates

sponge digestive system

digest food intracellularly

cnidarians and platyhelminthes (flatworms )digestive system

one opening and no specialized regions

nematodes

primitive tract

simple tubular gut lined by epithelial membrane

earthworm digestive tract

specialized regions for ingestion, storage, fragmentation, digetion, and food absorption

vertebrate digestive system

complex, specialized system

components of vertebrate digestive system + function

mouth/pharynx- entry

esophagus- delivers food to stomach

stomach- digestion

small intestine- digestion and absorption

large intestine- absorption of water and minerals

cloaca/rectum- storage of waste

anus- expel waste

accessory digestive organs + functions

liver- bile

gallbladder- stores/concentrates bile

pancreas- pancreatic juice, digestive enzymes & bicarbonate buffer

function of mouth and teeth & difference for birds

chewing/mastication

birds- lack teeth, break food in 2 chambered stomach, gizzard uses ingested pebbles to pulverize food

different types of teeth & which feeding type exhibits which

incisors- cutting

canines- tearing, immobilization

premolars- shearing

molars- crushing, grinding

• herbivore- incisors, molars, premolars

• carnivores- canines, molars, premolars,

• omnivores- all 4

2 ways herbivores have overcome difficulty in digesting cellulose

1. 4 chambered stomach/foregut fermentation (ruminant)

2. hindgut fermentation

foregut vs hindgut fermentation

foregut- rumen and reticulum have anaerobic bacteria that breaks down cellulose, cows/sheep/deer

hindgut- in colon and cecum, less efficient bc products have already passed through small intestine, koalas/rabbits/horses

cellulase

enzyme that breaks down cellulase

rumen

largest/first stomach compartment

fermentation vat

reticulum

smaller/2nd chamber of stomach

sorts/traps food particles

cecum

pouch in large intestine

hindgut fermentation

different adaptations for feeding

herbivores- plants

carnivores- animals

omnivores- both

suspension feeders

trapped via sieve or tentacles

cnidarians, bivalve mollusks, some vertebrate

suction feeding

fast negative pressure by expansion of mouth

aquatic animals, some terrestrial invetebrates

active swimming

actively swim to capture prey

respiratory medium vs surface

medium- air/water

surface- membranes that gases diffuse across

difference in gas exchange for different animal groups

amphibians- across skin

echinoderms- protruding papulae

insects- extensive tracheal system

fish- gills

mammals- network of alveoli

which animals exhibit simple gas exchange

sponges, cnidarians, flatworms

4 steps of complex gas exchange

1. ventilation

2. diffusion

3. circulation by bulk transport

4. diffusion

advantages/disadvantages of air vs water breathers

air- more o2, co2 determines breathing, easy to move air across respiratory passage, risk of drying out

water- little o2, o2 determines breathing, difficult to move water across respiratory passage, no risk of drying out

structure of fish gill + function

located between oral and opercular cavity, they function as pump

water moves into mouth, over gill, and out of fish through operculum

countercurrent flow

blood flows opposite to water

which respiratory organ is most efficient across animals

fish gills

advantages vs disadvantages to having gills

must remain moist, water supports gills from collapsing/sticking together

enable fish to extract great amounts of o2 from water

how do insects and arachnids breathe

air enters through spiracles, transport directly through tissues

arachnids- book lung

why were gills replaced in terrestrial animals

air is less supportive than water

water evaporates

how do amphibians/reptiles/birds breathe + stuctures

amphibians- positive pressure breathing

reptiles- negative pressure breathing

lungs- channel air through parabronchi, unidirectional

what is blood + what is is composed of

special connective tissue

red blood cells, white blood cells, platelets, plasma

open vs closed circulatory systems

open- no distinction, hemolymph, grasshopper

closed- fluid enclosed in blood vessels, blood taken away from and back to the heart, earthworm

mollusks groups circulatory sytems

gastropods- open

cephalopods- closed

circulatory system in fish

true 2 chamber pump heart

circulatory system in amphibians

double circulation

3 chambered heart

pulmonary vs systemic ciculation

pulmonary- blood between heart and lungs

systemic- blood between heart and rest of body

circulatory system in reptiles

septum partially divided ventricle

circulatory system of mammals, birds, and crocodilians

4 chambered heart

right atrium receives blood from body

left atrium receives bloody from lungs

birds and mammals- double circulation

advantages of double fertilization

1. increased supply of blood to tissues

2. increases uptake of o2