Download Internal transport

Animal notes
Evolution of Animals
• Fossil record of invertebrates is incomplete
because soft-bodied animals are poorly preserved
as fossils.
• All animals probably evolved from Protists.
• The classification of animals is based on the level
of organization or number of germ layers,
symmetry, type of coelom, body plan, and
presence or absence of segmentation.
• The following evolutionary tree is based on these
features and shows a possible evolutionary
relationship between the animals.
Evolutionary tree
Levels of Organization
• Three levels or organization: cell, tissue, or
organ
• One of the main events during animal
development is the establishment of germ
layers.
• If two germ layers (ectoderm and endoderm)
are present, then the animal has the tissue level
of organization.
• If all three germ layers (ectoderm, endoderm,
and mesoderm) are present, then the animals
has the organ level of organization.
Type of Body Plan
• Two body plans are present in the animal
kingdom:
• Sac plan:
• Incomplete digestive system with only one
opening.
• Ex: Jellyfish
& planaria
•Tube-within-a-tube plan:
•Complete digestive system.
•Two openings allows for specialization
along the length of the tube.
•Ex: Roundworms, earthworms, insects
Type of Symmetry
• Animals can be asymmetrical, radially
symmetrical, or bilaterally symmetrical.
• Asymmetrical animals have no particular
symmetry.
• Radial symmetry means the animal is
organized similar to a wheel.
• Bilateral symmetry means the animal has
definite right and left halves.
• Bilateral symmetry leads to cephalization
(brain and sense organs located an anterior
end of animal).
Type of Coelom – for animals with bilateral symmetry
• A true coelom (in coelomates) is an internal body
cavity completely lined with mesoderm, where
internal organs are found. Benefits:
• Allows organs to freely move, grow, and develop
independently of the body wall
• Fluid cushions and protects organs from shocks –
in some acts as a skeleton
• Allows for separation of digestion & circulation
• Allows for increase in size & metabolic rate.
• Coelomates are either protostomes or
deuterostomes (explained a few slides later).
• Ex: Annelids, mollusks, arthropods
•Animals that have a pseudocoelom have a body
cavity incompletely lined with mesoderm.
•No circulatory system – fluid in
pseudocoelom transports oxygen & nutrients
•Pressure of fluid inside also provides support
as would a skeleton
•More mobile, more complex reproductive &
digestive systems.
•They can store wastes for discharge out of
the body.
•Ex: Roundworms, rotifers
•Acoelomates have mesoderm but no body cavity.
•Movement squeezes & distorts the body,
restricting the flow of nutrients and other
materials
•Have no circulatory system. Must rely either on
diffusion or on muscle contractions for the
transport of nutrients, respiratory gases, and
waste products around the body. (Less efficient
than heart & blood vessels which develop in
those with a coelom.)
•Ex: Flatworms
Protostomes vs. Deuterostomes
•During development, when the embryo resembles
a tiny globe of cells, a small pucker develops on
one side of the embryo.
•This grows into a pocket, and allows some cells
to migrate inside to form an additional layer of
cells within the outer layer.
•In the Protostomes, the mouth develops from the
edge of this pocket; the anal opening develops
later.
•In the Deuterostomes, the reverse is true; the
pocket edge develops into the anus, and the mouth
is formed later.
Segmentation
• Segmentation is the repetition of body parts
along the length of the body.
• Animals can be segmented or nonsegmented.
• Segmentation leads to specialization of parts
because the various segments can become
differentiated for specific purposes.
• Ex: annelids, arthropods, and chordates
(includes vertebrates).
•
•
•
•
•
•
•
Phylum Porifera - Sponges
Meaning: Pore-bearing
Symmetry – none (asymmetrical)
Organization – cellular level
Acoelomates – NA
Body plan - NA
Non-segmented
Habitat – fresh & salt water
Osculum
Amebocyte
Collar cell
Flagella
Pore channel
Pores
Spicules
Epidermis
Internal
cavity
Filaments
Flagella
Collar cell
Life processes
• Support - spicules (act like bones for the
sponge)
• Diet - filter feeders – filter bacteria, protists,
and sometimes small crustaceans
• Feeding –
– Filaments trap food
– Collar cells digest food (engulf food particles
(endocytosis), digest them, and pass them to
amoeboid cells.
•Movement:
- Swim as larva
- Sessile (permanently attached to a
surface) as adults.
•Response - no nervous system.
•Excretion - through the osculum.
•Respiration - take in oxygen as water passes
through body – diffusion.
•Internal transport - ameboid cells transport
nutrients around the body from cell to cell
•Reproduction –
•Hermaphrodites (make eggs & sperm).
•Asexually by:
•Budding: Produce internal buds called
gemmules (cells containing ameboid
cells, organic molecules, & spicules) that
can grow into new sponges when the
conditions are more favorable
•Regeneration: Growth of a whole
organism from a fragment
•Sexually:
•Release sperm into the water
•Sperm enters pores of another sponge of
same species
•Fertilizes egg within
•Larva released through osculum
•(see life cycle diagram – separate sheet).
•Some will release eggs & sperm into internal
cavity, larva develops, and is released into
water.
•Poor reproductive odds!!!
http://www.eeob.iastate.edu/faculty/DrewesC/htdocs/Q-sponge.htm
5.
1.
2.
1. Sperm
2. Egg
3. Dividing cells
(spongocoel)
4. Larva
5. Larva released
6. Flagella (moves)
7. New sponge develops
6.
3.
7.
4.
Phylum Cnidaria
•Named for – specialized stinging cells called
cnidocytes (contain the stingers called
nematocysts – these may contain poison)
•Symmetry – radial
•Organization – have endoderm & ectoderm tissue level
•Acoelomates – NA
•Non-segmented; sac body plan
•Habitat – mostly salt water, hydra found in fresh
water
Tentacle
Mouth
Epidermis----
Ovary
Stinging capsule
-------Gastrodermis
------------------------GVC
– Gastrovascular cavity
Bud
Testis
Sperm
Developing egg
Basal disc
Life processes
•Movement:
•Directional
•Move by contraction & expansion of
body
•Tentacles can grab prey
•Response:
•Nerve net – interconnecting nerve cells
communicate with sensory cells
throughout body
•Support
•Hydrostatic skeleton –fluid-filled closed
chambers; internal pressures generated by
muscle contractions cause movement as
well as maintain the shape of the animals
•Diet – protists and small animals
•Feeding –
•Sting prey with nematocysts
•Stuff food into mouth using tentacles
•Don’t chase their prey – but movement of
medusa can help drawn food in towards
body.
•Food passes into GVC (gastrovascular
cavity)
•Digestion – cells of gastrodermis take in food
through endocytosis and digest the food in
their vacuoles.
•Internal transport:
•Nutrients and oxygen pass from cell to
cell through the process of diffusion
•Respiration:
•Diffusion between epidermal cells and
exterior watery environment, and
between gastrodermal cells and fluid
within GVC
•Excretion:
•Wastes are excreted through the mouth
•Reproduction:
•Usually appear as separate males & females
•Sexual reproduction – see life cycle diagram
given separately
•Jellyfish –
•Release eggs & sperm into water
•Swim as larva, settle as polyps, then
divide to become medusa
•Several young from one fertilized egg
•Hydra – release egg or sperm from body
wall; meet, swim as larva, settle as polyp
Medusa
Egg
Blastula
Planula
Polyp
Sperm
•Asexual reproduction
•Budding – cluster of cells form, break off ,
grow into adults
•Regeneration – fragments develop into new
animals
Phylum Platyhelminthes
•Meaning – flatworms
•Symmetry - bilateral
•Sac body plan; non-segmented; acoelomates.
•Organization - 3 germ layers – endoderm,
ectoderm, & mesoderm – organ level
•Have organs for all life processes except
respiration and circulation
•Habitat – fresh or salt water, moist environments,
inside host
•Examples:
Tapeworms
Marine flatworms
Flukes
Freshwater planarians
Planarians • Lifestyle - free-living
• Habitat - freshwater
• Movement – secrete slime, push through with
cilia, muscles
• Excretion – flame cells – interconnecting canals
throughout body – remove water
• Response - small brain
- ladder of nerves
- light-sensitive eyespots
- Auricles sensitive to chemicals
(all located in the head - cephalization).
Eyespot
Brain
Auricle
Longitudinal
nerve cord
Transverse
nerve cord
GVC
Pharynx
Flame
cells
Mouth
Mesoderm
Endoderm
Ectoderm
GVC
Cilia
Excretory pore
Flame
cells
•Diet – plankton (small worms or crustaceans)
•Feeding – wrap around prey
- secrete slime
- extend pharynx –
sucking motion tears
up and swallows food
•Digestion – occurs in GVC
•Support - None
•Respiration and internal transport - Flattened
body allows for diffusion of oxygen &
nutrients from cell to cell
•Gender - hermaphrodites
•Sexual reproduction – cross-fertilization,
have sex, exchange sperm, each planaria gets
pregnant - 2 sets of young hatch from eggs 2-3
weeks later.
•Asexual reproduction – capable of regeneration;
1 worm can even grow 2 heads or 2 tails!!
Phylum Nematoda (Roundworms)
•Non-segmented
•Bilateral symmetry
•Organization - 3 germ layers – endoderm,
ectoderm, & mesoderm – organ level
•Pseudocoelomates (body cavity) – filled with fluid
– space for organs
•Tube-within-a-tube body plan – complete digestive
tract with mouth and anus.
•Habitat – fresh or salt water, soil, inside host (both
plants & animals)
A.
B.
C.
D.
Mouth
Pharynx
Intestine
Anus
E.
Body wall
F.
G.
H.
I.
Pseudocoelom
Excretory tube
Excretory pore
Ovary
J.
Oviduct
K. Uterus
L. Testis
M.
N.
Vas deferens
Seminal vesicle
O. Spicule
P. & Q. Nerve cords
Life Processes
•Internal transport - fluid in pseudocoelom
transports nutrients & oxygen
•Support – fluid in pseudocoelom provides
support (hydrostatic skeleton).
•Respiration - Breathe through their skin diffusion.
•Movement - longitudinal muscles – move
with whiplike motion – inefficient in water,
good in soil & host.
•Response – brain and nerve cords
•Excretion – waste is removed through the
anus
•Feeding & digestion –
•Feed using muscular pharynx which
shoots out from mouth
•Food is digested in intestine
•Gender - appear as separate males &
females
•Sexual reproduction – male injects sperm
into female, she lays eggs.
Phylum Annelida (segmented worms)
• Symmetry - bilateral
• Organization - 3 germ layers – organ level
• Coelomates -have a body cavity – more
complex organs
• Tube-within-a-tube body plan – specialized
organs in digestive tract
• Segmented both externally, and internally by
partitions called septa.
• Habitat – fresh or salt water, soil
Giant earthworm video clip:
• Support - a hydrostatic skeleton
• Movement - move by alternating contraction of
longitudinal and circular muscles found in each
segment.
– Partitioning of the coelom permits each body
segment to move independently.
• Respiration - breathe through their skin.
• Internal transport - closed circulatory system
with blood vessels that run the length of the body
and branch to every segment.
•Excretion - nephridia (tiny tubules found in
each segment) remove nitrogen waste through
openings in body wall; anus removes waste
from digested food.
•Response - a brain connected to a ventral solid
nerve cord with ganglia in each segment.
•Three classes –
•Polychaeta – marine worms
•Oligochaeta – earthworms
•Hirudinea - leeches
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
Mouth
Pharynx
Esophagus
Crop
Gizzard
Intestine
Anus
Aortic arches (hearts)
Dorsal blood vessel
Ventral blood vessel
Brain
Ventral nerve cord
Clitellum
Setae
Clitellum
Testis
Sperm reservoir
Ovary
Seminal
receptacle
Excretory pore
Nephridium
Tubule
H. Intestine
I. Coelom
J. Muscle
K. Muscle
L. Epidermis
L1. Cuticle
M1. Blood vessel
M2. Blood vessel
N. Nerve cord
O. Nephridium
P. Setae
Earthworms
• Head is not well-developed; no parapodia.
• Have pairs of setae in each segment; when
muscles contract in each segment, setae anchor
in the soil, and aid locomotion.
• Most scavenge for food in the soil – feed on
leaves & decaying matter
• Digestion: Mouth  Pharynx (swallows food)
 Esophagus (connects pharynx & crop) 
Crop (stores food)  Gizzard (grinds food –
contains small stones swallowed by the worm)
 Intestine (digests food)
•Internal transport - Five “hearts” (aortic arches)
pump blood and a branch blood vessel reaches
each segment.
•Gender - These worms are hermaphroditic.
•Reproduction
•Meet at clitellum, which secretes a ring of
mucus
•Each injects sperm into mucus
•Tube slides forward, picking up eggs
•Tube slides off body & is left behind
•Fertilization occurs within tube
•Worms hatch in a few weeks – no larval stage
• Segmentation in earthworms is evidenced by:
– Body rings
– Coelom divided by septa
– Setae on most segments
– Ganglia and lateral nerves in each segment
– Nephridia in most segments
– Longitudinal and circular muscles in each
segment
– Branch blood vessels in each segment
•
•
•
•
•
•
•
Phylum Mollusca
Meaning – soft-body
Coelomates (reduced in some)
Symmetry – bilateral
Organization – organ level
Tube-within-a-tube body plan
No segmentation
Found in fresh or salt water, and on land
Molluscan diversity
• 3 distinct parts to all mollusk bodies:
– Visceral mass – soft-bodied part
containing organs
– Foot – muscular part used for
movement
– Mantle – membrane covering
visceral mass; in some molluscs, it
secretes the shell
• Molluscan groups are distinguished by
a modification of the foot.
• Bivalves
– Ex: clams, oyster, scallops & mussels
– A coelom is present but reduced
– Support - Two shells held together by muscles
– Respiration - using gills hanging on both sides
of visceral mass
– Movement - have a hatchet-shaped foot – in
some species, this can allow for movement –
most are sessile
– Response - no cephalization – no distinct head
– have 3 pairs of ganglia connected by nerves
to control body.
• Internal transport – heart pumps blood into an
aorta, then through sinuses rather than blood
vessels (open circulatory system).
• Feeding - filter feeding.
– Water enters by an incurrent siphon; exits by
excurrent siphon.
– Food trapped on the gills is swept toward
the mouth.
• Digestion - mouth with labial palps (helps
bring food to mouth), an esophagus, a
stomach, and an intestine.
•Excretion - 2 kidneys remove waste from cavity
around heart; food waste passes through anus,
which empties at an excurrent siphon.
•Reproduction:
•Sexes are usually separate
•A single gonad (either ovary or testis) is
located around the coils of the intestine.
•Some clams release both eggs & sperm into
water
•Other species release sperm only into water,
enters female, and fertilizes egg at gills.
Muscle
Muscle
Mouth
Mantle
Foot
Gills
Stomach
Muscles
Esophagus
Digestive gland
Heart
Muscles
Anus
Excurrent
siphon
Incurrent
Mantle siphon
Mouth
Intestine
Gills
Phylum Echinodermata
• Habitat – salt water
• Examples: Sea lilies, feather stars, sea
cucumbers, brittle stars, sea urchins, sand
dollars, & sea stars
• Symmetry – radial as adult, larva is a freeswimming filter feeder with bilateral
symmetry.
• Organization – organ level
• Coelomates; non-segmented
• Tube-within-a-tube body plans
Echinoderm diversity
Sea Stars
• Support - endoskeleton consisting of spine-bearing,
calcium-rich plates; spines protrude through skin.
• Movement - water vascular system
– Water enters this system through the sieve plate
(aka madreporite), passes into a stone canal, then
to the ring canal, into radial canal, then into
ampullae, and into tube feet; expansion and
contraction of tube feet move the sea star along.
• Internal transport - fluid in body cavity & water
vascular system
– Cilia lining the peritoneum move fluid through coelom to
transport nutrients & oxygen.
• Respiration – Gas exchange occurs across skin
gills and tube feet
• Excretion - waste diffuses through fluid in coelom
& body wall; food waste passes through anus
• Feeding and digestion –
– Eat bivalves (2-shelled mollusks)
– Everts its cardiac stomach inside the shells and
secretes enzymes; partially digested food is
taken in.
– Digestion continues in pyloric stomach with
enzymes made in digestive glands in each arm
•Response –
•Central nerve ring with radial nerves in each arm
•Sensory tube feet at end of each arm to “taste”
the water
•Photosensitive eyespot at the end of each arm
•Reproduction – gonads in each arm – open directly
to outside
•Asexually - by regeneration – 1 small piece can
grow into a new sea star
•Sexually - by releasing eggs & sperm into water
1.Rays/arms
2. Anus
3. Madreporite/
sieve plate
4. Stone canal
5. Ring canal
6. Radial canal
7. Ampulla
8. Tube feet
9. Spine
10. Mouth
11. Ambulacral groove
1. Madreporite/
Sieve plate
2. Digestive
Gland
3. Sex organs
4. Ampulla
5. Ray/arm
6. Eyespot
7. Radial canal
8. Spines
9. Stomach
(2 parts – pyloric
And cardiac)
Phylum Arthropoda
•
•
•
•
•
•
Meaning – “jointed foot”
Symmetry – bilateral
Coelomates – complex internal organs
Tube-within-a-tube body plan
Segmented
The most varied and numerous of animals (over
1 million identified, probably 30 million really
exist!!)
• Five Classes – Crustaceans, Insects, Arachnids,
Millipedes, & Centipedes
Arthropod diversity
•
•
•
•
•
Crustaceans
Mostly marine; crayfish, shrimp, crab, lobster
Response: compound eyes, 2 pair of antennae,
brain, & ventral nerve cord.
Feeding: specialized mouth parts.
Digestion: stomach – 2 regions – 1 to grind food, 1
to filter coarse particles & prevent them from
entering digestive glands where digestion takes
place.
Locomotion: 5 pairs of legs include a first pair of
pinching claws (called chelipeds).
• End of abdomen has uropod & telson used to
help crayfish move backwards.
• In the crayfish, head and thorax are fused into
a cephalothorax which is covered on the top
and sides by a carapace.
• Internal transport - The crayfish has an open
circulatory system - heart pumps blood into a
hemocoel consisting of sinuses where the
hemolymph flows about the organs.
• Respiration takes place by gills under the hard
carapace.
• Excretion - Green glands – excrete metabolic
wastes through duct; food waste passes out
through anus
•Reproduction - the abdominal segments have
swimmerets, which are used to hold the eggs in
the female.
•Sexes are separate in the crayfish; can tell
male from female by looking at first pair of
swimmerets – point upward in male
•Swimmerets - transfer sperm to female.
1. Cephalothorax
2. Abdomen
3. Carapace
4. Antenna
5. Antennule
6. Mandible (jaw)
7. Maxilla
8. Cheliped (claw)
9. Maxilliped
10.Walking legs
11.Swimmerets
12.Brain
13.Green gland
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
Mouth
Esophagus
Ganglion (nerve)
Stomach
Digestive gland
Gills
Anus
Intestine
Testis
Heart
Telson
Insects
• Many exhibit social behavior, such as bees or ants.
• Response: in addition to brain & nerve cord, head
usually bears a pair of antennae, compound eyes,
simple eyes, and in some tympanum for the
reception of sound waves.
• Locomotion: thorax bears three pairs of legs and
up to 2 pairs of wings.
• Excretion - Malpighian tubules collect nitrogen
waste, which is added to digestive tract; waste
then passes out through anus.
Insect diversity
• Internal transport: open circulatory system;
heart pumps hemolymph into aorta that
leads to a hemocoel (contains sinuses),
where it circulates before returning to the
heart.
• Feeding: mouthparts specialized for diet –
for ex. chewing vegetation, siphoning
nectar.
• Digestion: mouthparts chew food, crop
stores, digestion occurs in stomach &
intestine.
•Some insects, such as grasshoppers, are
adapted to a terrestrial life:
•Respiration - tracheae (small tubules);
open to outside by holes called
spiracles (on abdomen)
•Have wings that allow them to evade
enemies
•Third pair of legs is suitable for
jumping.
• Reproduction:
• Mate by having sex
• Female grasshopper has ovipositor at posterior
end to dig hole and lay eggs.
• Grasshoppers undergo gradual metamorphosis
from nymph to adult (referred to as incomplete
metamorphosis).
• Butterflies undergo complete metamorphosis,
changing from larva to pupa to adult.
1.
2.
3.
4.
5.
6.
Head
Thorax
Abdomen
Antennae
Simple eyes (3)
Compound eye (2)
7. Auditory membrane (ears)
8. Wing
9. Ovipositor (F only)
10. Spiracles
11. Jumping leg (2)
12. Walking legs (4)
13.Mouth
14.Pharynx
15.Esophagus
16.Crop
17.Gizzard
18.Cecum
19.
20.
21.
22.
23.
24.
Intestine
Anus
Malpighian tubules
Heart
Aorta
Salivary gland