Download Animal Development

Kingdom Animalia
Defining Characteristic: Multicellular
eukaryotic heterotrophs that have
tissues made up of specialized cells
with no cell walls.
All animals carry out 5 essential
functions to stay alive
1) Feeding: Need to ingest
other organisms /
substances for organic
supply of molecules.
• Herbivores, carnivores,
omnivores,
detritivores, filter
feeding, parasitic, etc.
2) Movement: related to food
source or themselves as
food sources.
• Even sessile animals
All animals carry out 5 essential
functions to stay alive
3) Respiration = Take in O2 and release CO2
to help break down nutrients from
ingestion.
4) Circulation = Transport nutrients, gases,
products, and waste products to and
from all cells.
5) Excretion = elimination of nitrogenous
metabolic waste (ammonia)
Animal Evolution
Protozoan ancestor: Evidence in the different
methods of locomotion (?)
Fossil record indicates that, like all kingdoms,
animals have been getting more complex over
time
More complex?
The more complex the animal:
• The more types of specialized cells and higher
degree of internal organization
• Greater efficiency in the 5 essential functions
Two (non-taxonomical) groups of
animals
1. Invertebrates: 95% of all animal species
• Do not have backbone
• Great diversity; microscopic dust mites to
giant squid (20m)
2. Vertebrates: other 5% of animal species.
• Includes fishes, amphibians, reptiles,
birds, and mammals.
Animal Development
Developmental stages from zygote to gastrula same for all animals
1)
Blastula formation: Zygote divides (how?) until it is a sphere made
of a single layer of cells with a fluid filled center.
2)
Gastrula formation: Cells on one side of blastula continue to
divide and get pushed inward
•
3)
This will result in two cell layers (germ layers)
Mesoderm formation: (most animals) a middle cell layer forms b/w
inner and outer cell layers
Animal Development
Due to multicellularity and gastrulation all animal’s
systems develop from these distinct germ (cell)
layers
1)Ectoderm: Outer germ layer covering the surface
of embryo, gives rise to the outer covering of the
animal and, in some phyla the central nervous
system.
2)Endoderm: Inner most germ layer that lines the
digestive tube, gives rise to digestive tract and
organs derived from it (liver & lungs in verts.)
3)Mesoderm: between the ecto and endoderm.
Gives rise to muscles, and most other organs
The opening to the gastrula
can develop into one of two
things and is used to
classify animals:
1) Protostomes: animals
whose mouth develops
from gastrula opening.
2) Deuterostomes: animals
whose anus develops from
gastrula opening.
Animal Body
Cavities
Only animals with
mesoderm can be
classified as these.
Some animals have no
body cavity or coelom.
Acoelomates
Pseudocoelomate: Body
cavity is in between
endoderm and
mesoderm.
Coelomate: Body cavity
completely surrounded
by mesoderm.
Importance and advantages of a
coelom
Provides a space for internal organs to be
suspended so that they are not pressed or
squished by muscle movements.
• Allows for more complex motion.
Allow for more specialized body regions to
develop, which results in room for organs
to grow and expand.
• Larger body sizes.
Comparing Invertebrates
Invertebrate solutions to the 5
essential functions of animals
Primitive to complex
Feeding and Ingestion
Incomplete digestion: digestive tract has one
opening that serves as both the mouth and
anus.
• Cniderians, Platyhelminthes, Echinoderms
(convergent)
• Incomplete Digestive Systems
Mouth/anus
Gastrovascular cavity
Digestive
cavity
Cnidarian
Pharynx
Mouth/anus
Flatworm
Feeding and Ingestion
Complete digestion: digestive tract has two
openings which is the beginning and end
of digestion.
• Nematodes, Annelids, Molluska,
Arthropods
Complete
digestion
Intestine
Gizzard
Crop
Pharynx
Mouth
Annelid
Anus
Pharynx
Crop
Anus
Arthropod
Mouth
Stomach and
digestive glands
Rectum
Intestine
Respiration
Aquatic invertebrates:
• Primitive; diffusion of gasses through skin
and gastrovascular cavity.
• Poriferians, Cniderians, Platyhelminthes,
Nematodes,
Respiration
Aquatic
invertebrates:
• Complex:
external gills
• Mollusks,
Annelids,
Arthropods,
Respiration
Terrestrial Invertebrates: Need to place
organs inside coelom to keep moist
• Book lungs (Arachnids, Mollusks)
• Trachea (insects)
Circulation
Primitive invertebrates use diffusion to
transport materials (small, thin bodies)
Complex / larger have 2 kinds of systems
1.Open circulatory system:
– Blood is only partially contained in open
blood vessels.
– Heart(s) pump blood through coelom which
eventually returns
– Insects, mollusks
Circulation
2. Closed circulatory system:
• Blood stays within the entire system (blood
vessels and heart)
• Materials reach body tissues by diffusing
through walls of blood vessels
• Characteristic of larger, more active
animals. More efficient due to more
pressure
• Annelids, some mollusks
Heartlike structure
Small vessels in tissue
Blood vessels
Annelid: Closed
Circulatory System
Heart like structures
Excretion
Get rid of ammonia from protein metabolism,
and regulate amount of water in body.
Diffusion (poriferians, Cniderians)
Flame cells (flatworms)
Nephridia (annelids, and mollusks)
Malpighian tubules (arthropods)
Flame Cells
Excretory tubules
Flame Cell
Flatworm
Excretory tubule
Movement and Support
Animals have tissues called muscles that
contract and relax in order to move the
animal.
These muscles need to work together with
some sort of skeletal system
3 types
Movement and
Support
1) Hydrostatic
Skeletons:
(cniderians, annelids)
muscles surround a
fluid-filled body cavity
that supports the
muscles.
• When the muscles
contract, they push
against fluid in the
body cavity, causing
the body to change
shape.
Movement and Support
2) Exoskeletons: an external
skeleton made of chiten or
calcium carbonate.
• Muscles on the inside
• Arthropods and mollusks
Movement and Support
3) Endoskeletons:
Skeleton inside of
body cavity.
• Muscles on the
outside of skeleton
• Echinoderms,
chordates