Lecture 11/12/13: Invertebrates Flashcards
havent gone over lecture 11 or 13
what was the common ancestor between fungi and animals?
(probably) a colonial flagellated protists and may have resembles modern choanoflagellates
what does zoology mean?
study of animals
how do we define an animal?
- multicellular
- ingestive heterotrophs (absorb material and break it down for nutrients)
- don’t have cell walls (plasma membrane but no cell wall)
- two unique types of cells
- sexual reproduction
what does heterotrophs mean?
can’t produce energy on their own, therefore need to consume something internally and break it down for energy
how are the multicellular bodies of animals held together?
by extracellular structural proteins, especially COLLAGEN
what do plant/fungi cells have that animal cells don’t?
cell walls
animal cells have unique intercellular connections such as ___ ________, _____, and ____ _______.
tight junctions; desmosomes; gap junctions
what are desmosomes? where can they be found? how do they help?
- special structures in animal cells that act like a glue to hold cells together
- found in tissues that experience a lot of stretching or stress (like skin or heart muscle)
- help keep cells firmly attached to each other, which provides strength and stability to the tissue
what do the intercellular junctions in animal cells do?
they hold tissues together
what are intercellular junctions made of?
structural proteins
what are the two unique cell types of animals?
- NERVE cells: IMPULSE CONDUCTION. send and receive signals throughout your body to help you think/move/feel- body’s communication network
- MUSCLE (or muscle-like) cells: MOVEMENT. contractile and allow for movement of the animal
what stage is usually dominating the life cycle of animals?
diploid stage
most animals reproduce…
sexually
what does embryology mean?
the study of the development of cells
in most species, a small _______ ______ fertilizes a larger ________ ________
flagellated sperm; nonmotile egg
what is a nonmotile egg?
an egg that cannot move on its own
what does the zygote undergo that leads to the formation of a multicellular, hollow ball of cells called blastula?
cleavage; a succession (development) of mitotic cell divisions
what are the multicellular, hollow ball of cells called?
blastula’s
what happens during gastrulation?
SLIDE: part of the embryo folds inward which forms layers of embryonic tissues (and then develops into body parts)
CHAT: ball of cells starts to organize into layers, which later forms different body parts
what’s the difference between gastrulation and gastrula?
GASTRULATION: the PROCESS where the embryo fold inward to form different layers of cells
GASTRULA: what the embryo is called during and after this process
what is a larva?
a young, immature form that looks very different from the adult animal. Eats different food and may live in a different place than the adult
what will larva eventually go though when it changes into adult form?
metamorphosis
animals can be categorized by…
the symmetry of their bodies
what are the types of animal body symmetry?
- Bilateral symmetry
- Radial symmetry
- Spherical symmetry
what animal has radial symmetry?
sea anemones
what does bilateral symmetry inquire?
- dorsal (top) side
- ventral (bottom) side
- left and right side
- anterior (head) end
- posterior (tail) end
what does the “dorsal” side mean?
refers to the back or upper side of the animal
- think of ‘mon dos’ in french means my back
what does the “ventral” side mean?
refers to the “belly” or underside of the animal
what does “anterior” mean?
- for humans, refers to the front of the body (face, chest, belly)
- for animals, refers to where the head-end is
what does “posterior” mean?
- for humans, refers to the back side of the body (spine or butt)
- for animals, refers to the where the tail-end is
what is linked with bilateral symmetry?
cephalization
what is cephalization?
over time animals have evolved to have most of their sensory organs at the front or head. Along with this, the nervous system becomes more focused in the head, with a nerve cord running down toward the tail
the symmetry of an animal generally fits its ______
lifestyle
animals that move a lot are generally what type of symmetry?
bilateral
animals central nervous system allows them to…
coordinate complex movements such as crawling, burrowing, flying, swimming
how do you get different layers of cells?
when the cells fold over each other aka gastrulation
how many layers of embryonic tissue (germ layers) do animals have typically? how many do humans have?
2-3 (humans have 3)
what are the 3 germ layers called?
- ectoderm
- endoderm
- mesoderm
animals that only have two germ layers are called….
diploblastic
what is the ectoderm?
the OUTER germ layer of an embryo of animal cells.
- eventually forms the skin/outer covering of the body
- in some animals, it also helps form central nervous system
if you have three layers, what is it called?
tripoblastic
what is the endoderm?
the INNERMOST layer of an embryo of animal cells
- forms the inside lining of the digestive system
- creates organs like the liver and lungs in animals with back bones (vertebrates)
what’s the difference between vertebrates and invertebrates?
Vertebrates have a backbone or spine (like humans, bird, fish and reptiles), where invertebrates do not have a back bone. Example: insects, worms, jellyfish, and snails
what is the mesoderm?
the layer that lies between the endo and ectoderm layers of an animal cell embryo.
- develops into the muscles and most other organs between the digestive tube and the outer covering of the animal
what does pseudo mean?
they have a body cavity but it isn’t lined with mesoderm
what does the fluid in the pseudocoelom act as?
hydrostatic skeleton and a circulatory system
what are the three phyla of lophophorate animals?
- Ectoprotca
- Phoronida
- Brachiopoda
what is the shape of lophophore?
horseshoe-shaped or circular fold of the body wall that has ciliated tentacles
what do the ciliated tentacles do?
bring food (nutrients) to mouth
what type of worms have bodies much like those of flatworms?
proboscis worms or ribbon worms
whats different between the bodies of ribbon worms and flatworms?
ribbon worms have a small fluid-filled sac that is a reduced version of a true coelom
what is a coelom?
a flexible space inside the body that holds organs and provides them with room to function without being compressed/damaged (body cavity lined by the mesodermal tissue)
nearly all nemerteans are _____, but there are still some that inhabit _____ freshwater or damp soil, as some are swimmer and some are burrowers.
marine
what do nemerteans not have in their body?
a heart
how is the blood moved around in a nemertean?
the blood is propelled by muscles squeezing the vessels
what is a proboscis?
something the worm uses to capture prey; muscular, tube-like extension they push out of their mouth
what are examples of molluscs?
- scallops
- snails
- slugs
- octopus
- clam
- squid
- oyster
- mussel
what are the characteristics of mollusca?
- marine or terrestrial
- soft-bodied
- some are protected by hard shell
- similar body plan
where could i find molluscs?
anywhere. (marine, fresh water, terrestrial)
even though all molluscs look different, they have a similar body plan. What does this body plan include?
- muscular foot (for movement)
- visceral mass (to hold internal organs)
- mantle (shell)
what is the hard shell of mollusca made of?
calcium carbonate
how do many molluscs (like snails and slugs) feed?
by using a tongue-like organ with tiny teeth, aka radula, to scrape up food
what is the tongue-like organ on snails called?
radula
all annelids have ______ bodies
segmented (“little rings”)
where do annelids live?
moist environments (for gas exchange): sea, frshwater habitats, or damp soil
what are the 3 class that divide the phylum annelida?
- Oligochaeta (earthworms)
- Polychaeta (polychaetes)
- Hirundinea (leeches)
Oligochaetes are named for their…
relatively sparse chaetae or bristles made of chitin
what is chaetae?
small, bristle-like structures found on the bodies of segmented worms.
- help with movement by grip and traction as the worm crawls through soil or swims
how do earthworms eat?
eat their way through soil, extracting nutrients as the soil passes through the alimentary canal
what are worm ‘castings’?
their feces
earthworms till the soil, enriching it with their _______.
castings
what are nematodes?
non-segmented (pseudocoelomates) worms. round, with tough cuticle
where are nematodes found?
- most aquatic habitats
- wet soil
- moist tissues of plants
- the body fluids/tissues of animals
as the worm grows (nematodes), what happens?
it sheds its old cuticle periodically and develops a new/larger one
why are nematodes good in a way?
they decompose organic matter in the bottom of lakes and oceans (good cleaners/nutrient recyclers)
what are arthopods? give example
segmented coelomates that have an exoskeleton and jointed appendages; butterfly, spider, lobster, scorpions, crabs
what is the most successful phylum (animals)?
phylum arthropoda
why are arthopodes so successful?
three reasons:
1. body segmentation
2. a hard exoskeleton
3. jointed appendages
what do the groups of segments and appendages permit?
efficient division of labour among regions
what is the exoskeleton of arthopodes made of?
layers of protein and chitin
what phylum are sea stars (starfish) in?
Echinodermata
where does echinodermata get its name?
chino = spiny
derma = skin
-> spiny skin
what kind of symmetry do echinoderms have?
radial symmetry (but not perfectly)
what does the skin of sea stars look/feel like?
prickly from skeletal bumps
“star fish” are actually referred to as…
sea stars
how many arms are typically found on echinderms?
5
what do the tube feet of echinoderms function as?
locomotion, feeding and gas exchange. act like a suction disk
what are some other examples of echinoderms?
- sea cucumbers
- sea urchins
- feather stars
- sea lilies
- brittle stars
whats another way bilateral animals can be distinguished (separated)?
based on whether or not they have body cavity
what is a body cavity?
a fluid-filled space inside an animals body that separates the organs from the outer body wall
what is a true coelom?
a body cavity formed from tissue derived from mesoderm
what are animals with a true coelom called?
coelomates
some animals have a body cavity formed from _____, rather than mesoderm. what is this type of cavity called?
blastocel; pseudocel
what does the word “pseudocoel” mean?
false coelom
what are the animals called that have pseudocoel (body cavity that is not lined with mesoderm tissue)?
pseudocoelomates
animals without any body cavity are called…
acelomates
what are the functions of a body cavity? (3)
- cushions internal organs which helps to prevent internal injury
- can act as a skeleton for muscles to push against
- lets internal organs grow and move without affecting the outer body
what’re the 2 developmental modes for animals?
- protostome development
- deuterostome development
what’re the differences between the two developmental modes? (protostome vs deuterestome)
- cleavage pattern
- coelom formation
- blastopore fate
what is the cleavage pattern difference between protostome dev. and deuterostome dev.?
PROT:
- SPIRAL cleavage (cells divide diagonally to the vertical egg axis)
- DETERMINATE cleavage (fate of the cell is determined in early dev.). if the cell is separated from the rest of the embryo it cannot develop into a complete embryo on its own b/c its fate has already been decided
DEUT:
- RADIAL cleavage (cells divide parallel or perp. to vertical egg axis)
- INDETERMINATE cleavage (cells still has potential in the early embryo to develop into a complete embryo)
what is the difference between the dev. of archenteron of prots vs deuts?
PROTS:
schizocoelous dev. looks like the outline of a tree with a sac on the bottom of the stem
DEUTS:
enterocoelous dev. looks like the outline of a bunny
explain the schizocoelous dev
masses of mesoderm split to create the coelom
explain the enterocoelous dev.
mesoderm pinches off from the wall of the archenteron (the developing gut) and hollows out
what is blastopore?
the opening of the archenteron (developing digestive gut)
- depending on the type of animal, blastopore can develop into either the mouth or anus
what is archenteron? what is it also known as?
a blind pouch inside of the embryo
- “developing digestive tube/gut”
in protostomes, the blastopore usually develops into the mouth or anus first?
mouth
in deuterostomes, the blastopore usually develops into the mouth or anus first?
anus
where do invertebrates inhabit?
nearly all environments on earth
what is the phylum Porifera commonly known as?
sponges
where do sponges live?
freshwater and marine environments
how do sponges eat (what type of feeder)?
suspension feeders: they eat nutrients that come from water passing through food-trapping equipment. don’t hunt
what lines the spongocoel and creates a flow of water through the sponge with their flagella and trap food with their collars?
flagellated chaonocytes or collar cells
what are oscula?
the large openings or exit pores in a sponge’s body through which water flows out after it has been filtered for food
what does the body of a simple sponge resemble?
sac perforated with holes
what is the central cavity of a sponge called?
spongocoel
what do sponges lack?
true tissues
what are the two cell layers in the body of a sponge separated by?
the mesohyl: a gelatinous region
what can be found wandering through the mesohyl of sponges?
amoebocytes
what are the function of amoebocytes (found in the mesohyl of sponges)?
- transport/digest nutrients
- make the sponge’s skeleton (skeletal fibres within the mesohyl)
what are the two types of skeletal fibres that amoebocytes secrete?
- sharp spicules: made of calcium carbonate or silica
- flexible fibres: made from spongin (collagen protein)
most sponges are sequential hermaphordites, meaning…
they produce sperm and eggs at different times.
where does the sperm and eggs (gametes) come from for sponges?
special cells call chaonocytes and amoebocytes
all animals that have true tissues belong to the _______ (sub-kingdom under animalia)
Eumetazoa
what’s an example of an animal from the Phylum Cnidaria?
jellyfish, corals, hydras, sea anemones
what are Cnidarians known for?
their simple body structure and their ability to sting
what does the basic cnidarian body plan look like? how many variations are there?
sac with a central digestive compartment. two variations:
1. sessile polyp (like a cylinder that can’t move)
2. floating medusa (like a jellyfish)
what is the central digestive cavity in cnidarian’s?
gastrovascular cavity
how do polyps eat (since they can’t move)?
extend their tentacles and wait for prey
how do medusa move?
by drifting passively and by extracting their bell-shaped bodies
the tentacles of a jelly dangle from the ______ _______
oral surface
what are the tentacles of cnidarians covered in to help catch prey?
cnidocytes
what are the organelles inside cnidocytes that are the stinging capsules called?
nematocysts
when the cnidarians mouth is close, the gastrovascular cavity acts as a ______ ______
hydrostatic skeleton
during which explosion did most major groups of bilaterians emerge?
Cambrain explosion
whats an example of an acoelomate with gastrovascular cavities?
flatworms
where can i find a flatworm?
marine, freshwater and damp terrestrial habitats
are flatworms tripoblastic?
yes
what do flatworms lack?
a coelom
how do tapeworms eat (since they lack a digestive system)?
absorb nutrients directly through their skin
why are flatworms flat?
so that all cells are close to water for gas exchange and waste removal by diffusion
what does excretory system of flatworms use?
flame bulbs
what are flame bulbs?
help with fluid balance by moving waste out of body
what are rotifers?
pseudocoelomates with jaws crowns of cilia and complete digestive tracts
where could i find rotifers?
freshwater, sea or in damp soil
do rotifers have a separate mouth and anus
yes
in rotifers, what does the pseudocoelom also serve as?
circulatory system
what does the word “rotifer” refer to?
“wheel-bearer”. refers to the crown of cilia that create a water current to pull in food to the mouth
what are the jaws of rotifers called?
trophi
what are lophoporates?
group of animals (coelomate) that has lophophore
what is lophophore?
a feeding STRUCTURE with ciliated tentacles that surround the mouth and help pull in water for feeding.
how do earthworms develop their eggs?
two earthworms exchange sperm and then is stored while the clitellum produces a mucous cocoon. As the cocoon moves along the earthworms body, it collects eggs and the stored sperm, then slips off into the soil, where the eggs will develop
earthworms are hermaphrodites, meaning they….
have both male and female reproductive organs
why are most echinoderms (sea stars) prickly?
from skeletal bumps and spines that have various functions
where do the internal and external parts of echinoderms radiate from?
from the center
what’s the difference between gastrulation and cleavage?
gastrulation purpose: to make new body parts by the blastula cell folding inward on itself. creates gastula
cleavage purpose: to make as many new cells within the same original volume. creates blastula
