Zoology, 4,5 QUIZ

Cnidaria and Platyhelminthes

Bacteria, Archaea, Eukarya

3 domains of life

Plantae, Fungi, Animalia

taxa that belong to Eukarya

Metazoa

all animals belong to this clade but not Eumztaeoa

Eumetazoa

All animals except for sponges

Not existant

specialized nervous and muscle tissue in porifera?

Reef importance

support over 25% of all known marine species and are home to over 4000 species of fish, 800 of coral, and thousands of other plants and animals

• provide ecosystem services values at 9.9 trillion annually through fisheries, tourism and coastal protection, underling their importance for food security, resilience and the blue economy

Buffer

coral reefs do this, protecting inshore areas from the pounding of ocean waves, without them many beaches and building would become vulnerable to wave action and storm damage

Medicinal benefits of reef

biological products and medical applications- cardiovascular diseases, ulcers, leukemia, and skin cancer

tissues

morphologically and developmentally similar cells that are organized for specific functions

germ layers become tissue layers

development to tissue

cleavage

more cells produced through a series of cell divisions - fertilized egg

• produces a hollow ball of cells

blastula

hollow sphere of cells formed via cleavage

gastrulation

two-layered embryo, cells at one end of blastula fold inward

ectoderm

outer layer of blastula

endoderm

inner layer of blastula

diploplastic

animals that develop from two germ layers (ectoderm and endoderm)

polyp and medusa

two body forms of cnidarians

polyp

cylinder like body with mouth pointing up and the tentacles waving above

• sessile

medusa

bell-shaped body with the mouth pointing down and the tentacles hanging below (body plan similar to a jelly fish)

• free-swimming/floating

  • often rely on current of water to carry them along

radial symmetry

cnidarian body symmetry

• tentacles arranged around a central axis so that each part extends from the center

gastrodermis

inner tissue layer of cnidaria, develops from the endoderm layer

epidermis

outer layer of cindaria, develops from the ectoderm

mesoglea

space between two layers, gelatinous, non-living, cnidaria

gastrovascular cavity

opening to central internal space, mouth and anus and is surrounded by tentacles

diffuse, noncentralized

organization of nervous system of cnidaria

• lack true brains, instead have a system of separate, individual neurons located throughout the body

nerve net

system of separate individual neurons located throughout the body, fibers extending from the neurons connect them to each other

• stimulation of a neuron on one part of the body will result in a signal spreading out over the entire network of neurons throughout the body

antagonists

set of muscles that have opposite actions

longitudinal and circular muscles

cnidarians have these muscles

• run the length of an anemone and the circular around it

• in the body wall

hydrostatic skeleton

cnidarian skeleton, any change in the pressure applied to an enclosed, non-compresible fluid is transmitted to every portion of the fluid and to the walls containing vessel

• no change in volume with applied pressure

suspension feeding

feeding strategy of cnidarians, stab and inject food with venom

nematocyst

tentacles have a specialized structure in cnidarians

• barbed, venomous, coiled thread-like structure within the cells of the tentacles

chemical digestion in cnidarians

gland cells of the gastrodermis secrete enzymes that chemically break down the food

distribution of food in cnidarians

GVC branches to all parts of the body, including into the tentacle.

• nutrient molecules are transported to every cell of the body throgh these branches with the aid of movement of cilia

incomplete digestive system

any material that is not digested and moves out the body via the mouth

• cannot continuously feed

direct diffusion

gas exchange of cnidarians

ammonia

nitrogenous waste of cnidarians

symbiosis

a relationship between two or more organisms that live closely together

zooxanthellae

single-celled, photosynthetic marine alage, many cnidarians are symbiotically associated with populations of these

• algae transfer photosynthetically-derived, energy-rich molecules to their cnidarian host in return for access to nitrogen, phosphorus, and other nutrients from the cnidarian metabolism

• algae also get a place to live sequestered from the environment, protected from predators

• cnidarians get their color from them

• some cnidarians get 70-90% of their nutrition from the products of them

hard coral polyp

hard skeleton, calcium carbonate skeleton

zygote

one cell, one nucleus (sperm and egg union)

blastopore

opening of blastula leading to interior area

gastrodermis

endoderm develops into

epidermis

ectoderm develops into

360 detection

benefit of being radially symmetric and sessile

jellyfish

most efficient swimmer

jellyfish

alternate between polyp and medusa forms

• polyp (budding, asexual) produces medusa

• medusa then produces polyp via sexual reproduction (egg and sperm)

anemone and coral

more closely related to each other than jellyfish in eumztaeoa clade

for defense

nematocysts on tentacles and acontia

for grabbing food

nematocysts on tentacles

• prey comes in contact

• discharged and barbed ends penetrate and attach to prey

• barbs inject venom

porifera body walls

choanocytes form inner wall, pinacocytes form outer wall, layers not tissues

diffusion

how cnidarians excrete ammonia

coral colony

coral polyp divides to form additional genetically identical polyps which become a colony-asexual reproduction

• build the reef, coral do not just live there

coral reef

colonies of many different species of coral

natural stresses on reefs

• storms, cyclones, hurricanes

• el nino or other weather pattern that increases sea surface temperatures, decreases sea level, increases salinity

• predation: fish, marine worms, barnacles, crabs, snails, sea stars

• coral populations can often recover from these natural periodic disturbances but if they are occurring at the same time as other human induced disturbances the coral populations may not survive or recover

anthropogenic stresses on reefs

• climate change

• destructive fishing practices, overfishing

• pollution

• sedimentation - erosion caused by construction, mining, logging and farming increase sediment runoff that “smothers” corals

• careless tourism and recreational impacts

bleached

• zooxanthellae expelled due to increase water temperature

• white is color of coral skeleton

• coral are not dead

top three values of reefs

1. biodiversity and habitat (ecological)

2. coastal protection (environmental)

3. food and economic livelihoods (socioeconomic value)

Central aim of Paris Agreement

limit global average temperature rise below 2C, push for 1.5 to avert severe climate disruption

Climate change fighters

clean energy transition, climate finance, emissions reality, federal shifts and rollbacks, target pathways

platyhelminthes

flatworms

• belong to metazoa, eumetazoa, bilateria

• they are flat

• great diversity within this phyla

bilateral symmetry

symmetry of platyhelminthes

anterior

“head” of platyhelminthes

posterior

“tail” of platyhelminthes

dorsal

side facing up

ventral

side facing down

dorsoventrally flattened

platyhelminthes, flattened from top down

unidirectional movement

move with one part of the body primarily leading the way

triploblastic

platyhelminthes develop from three germ layers

• endoderm, ectoderm, mesoderm

mesenchyme

forms from the mesoderm, muscles and loosely packed connective tissue

• living tissue

central nervous system

platyhelminthes, consists of a mass of nerve cells called a brain in the anterior part of the body, and a nerve cord extending form the brain toward the posterior end of the body

eyespots

sensory cels that respond to light, clustered in the head of platyhelminthes

auricles

sensory cells that can detect water currents, solid objects, and chemicals, two flap-like projections on the heads of platyhelminthes

moving in a direction with purpose

platyhelminthes move with intent, sensory structures are responding to stimuli such as light or food and ending that information to the brain. which then sends signals to the muscles to produce movement, they choose where to go they don’t just move with the current

cilia on ventral surface

platyhelminthes have this, propel an organism, secrete mucus and use this to glide along it

hydrostatic skeleton of platyhelminthes

mesencyme, modified, filled with fluid and is non-compressible medium against which the muscles can act for support and movement

pharynx

connected to the mouth, can be turned to the outside through the mouth

• ingests food here

extends through the body

GVC of planaria and highly branched
- every cell is close enough to receive nutrients

predators or scavengers

strategies of most free-living flatworms

• locates food using chemosensory receptors in the auricles that extend from the head

incomplete

digestive system of planaria

diffusion gas exchange

planaria are really flay so that each cell is close enough to the environment to preform gas exchange

excretion of nitrogenous waste in planaria

diffuse out of body into water and into the surrounding aquatic environment

gametes

egg and sperm

testis

male gonad, produces sperm

ovary

female gonad, produces eggs

asexual reproduction

animal splitting into two can:

• occur by a fragment of an individual breaking off and developing into a new animal

• larva, immature animal from producing exact copies of themselves through cell division

• no fusion of gametes

asexual and sexual

reproduction in platyhelminthes

• asexual - spilt into two parts and then regenerate

• most are hermaphrodite, fertilization events, offspring have two parents genetically half of each of parent

hermaphrodites

each individual has both ovaries and testes

• most flatworms do not fertilizer their own eggs

endoparasites

live within their hosts

• flukes and tapeworms

• intermediate and definitive hosts

anatomy of fluke

oral sucker, ventral sucker, help fluke stay attached to host

hermaphroditic

flukes are this

tegument

epidermis is replaced, protects the fluke

definitive host

the host in which sexual reproduction occurs

• mature into adults

intermediate host(s)

host in which additional development occurs, but maturation and sexual reproduction do not occur

• asexual reproduction - produce many copies and then zip on out

tapeworms

• do not have a mouth or digestive tract - ingest nutrients all around them in the intestine of their host

• do not resemble free living planaria at all

• tegument

• microvilli which increases the surface area so that more nutrients may be absorbed

• scolex, spines/suckers, proglottids, immature vs mature, gravid

• hermaphroditic, will self-fertilize if no other tapeworm is present

microvilli

tapeworm has mini tiny folds, increase the surface area to absorb surrounding nutrients

• plan against lack of digestive system

scolex

anterior end of tapeworm, modified into this

• has spines and/or suckers that keep the tapeworm attached to it’s host

Proglottids

posterior to the scolex of tapeworms

• immature to mature to gravid

mature proglottids

developed male and female reproductive systems in them, fertilization of the eggs now occurs in each proglottid

gravid proglottid

each one contains fertilized eggs that will develop into individual tapeworms in the host, they break off and are released with the feces into the environment

• 50000 eggs

• fleas eat feces, and then jump on animals, animals bite and then consume fleas, back in definitive host

free-living flatworm diversity

SO FRICKEN MANYYYYYYYYY