Download Introduction to Animals symmetry 1st ppt

Introduction to
animals
Introduction to
Animals
Symmetry
Body Symmetry
Body Symmetry
• Symmetry is the
arrangement of body
parts around a
central plane or axis
• Asymmetry occurs
when the body can’t
be divided into
similar sections
(sponges)
Body Symmetry
• Radial symmetry occurs when
body parts are arranged around
a central point like spokes on a
wheel (echinoderms)
• Most animals with radial
symmetry are sessile
(attached) or sedentary (move
very little)
Body Symmetry
• Bilateral symmetry occurs when
animals can be divided into
equal halves along a single plane
• Organisms will have right and
left sides that are mirror
images of each other
• More complex type of
symmetry
Body Symmetry
• Animals with bilateral symmetry
are usually motile
• Animals have an anterior and
posterior ends
• Show cephalization
(concentration of sensory
organs on the head or anterior
end)
_______ Which of the following includes the most different kinds of organisms? a. class b. domain
c. family
d . phylum
e. kingdom.
Traits
Characteristics of Animals
• All multicellular
• Eukaryotes (cells with nucleus &
organelles)
• Ingestive heterotrophs (take in
food and internally digest it)
• Store food reserves as
glycogen
• Animals range in size from 25meter-long blue whales to
microscopic rotifers.
5. Most animals
have Hox genes.
Control head to
tail development
in embryos
Lions Feeding (Ingestion)
Support Systems
• Have some type of skeletal support
• Endoskeleton inside and made of
cartilage &/or bone
• Exoskeletons found in arthropods
– Cover the outside of the body
– Limit size
– Must be shed or molted making
animal vulnerable to predators
Cicada Molting Exoskeleton
Support Systems
• Worms and
echinoderms
(starfish) have
fluid-filled internal
cavities giving them
support
• Called hydrostatic
skeletons
Movement
• Animals such as sponges may be
sessile (attached & non-moving)
• Animals that move very little
are said to be sedentary (clam)
• Animals that can move are
motile
• Have muscular tissue to provide
energy for movement
SESSILE
Sponge
SEDENTARY
Chiton
MOTILE
Cheetah
Reproduction in Animals
• All animals are capable of
sexual reproduction
• Some animals like sponges and
earthworms are hermaphrodites
producing both eggs and sperm
• Hermaphrodites may exchange
sperm and NOT fertilize their
own eggs
Leeches Exchange Sperm
During Mating
leech
Mating
Reproduction in Animals
• Females of some animals
produce eggs, but the eggs
develop without being fertilized
• Called Parthenogenesis
• New offspring will be all female
Parthenogenesis occurs in some
fishes, several kinds of insects,
and a few species of frogs and
lizards
Parthenogenesis in the Komodo
Dragon
Female
Beetles
Mating
Courtship
Young
Male
Mating and
Mating
Behaviors
Levels of Organization
• Sponges are the ONLY animals that
have just the cellular level
• All other animals show these levels
– cell, tissue, organ, and system
• Cells may specialize (take own
different shapes and functions)
• Cells are held together by cell
junctions to form tissues
Atom
Molecule
or
compound
Levels of Organization
Organ
Tissue
Organ
system
Organelle
CELL
Life begins
Organism
Invertebrate
groups
Characteristics of
Invertebrates
• Simplest animals
• Contain the greatest number of
different species
• Most are aquatic (found in water)
• Do NOT have a backbone
• Includes sponges, cnidarians,
flatworms, roundworms, annelids,
mollusks, arthropods, and
echinoderms
Phyla Porifera
simplest animals
sponges.
Sponge - Porifera
Osculum
of
Sponge
Characteristics
o Simplest of all animals
o Contain specialized cells
but no other organization
level
o Most are marine
o Saltwater sponges are
brightly colored
o Freshwater sponges are
small and dull green color
o Size – 2 meters to 2 cm
Characteristics
oPorifera means
pore-bearing
oWater enters
through pores
bringing in food
and oxygen
oFilter feeders on
plankton
WATER
OUT
Water Flow
Through the
Sponge
WATER
IN
Osculu
m
Sponge Skeletons
SPICULES
VENUS
FLOWER
BASKET
Sponge Reproduction
o Sponges can
regenerate (regrow)
lost body parts
through mitotic cell
division (asexual)
o Sponges also
reproduce asexually
by budding
Branching Tube
Sponge
Vase
Sponges
Sea Anemone - Cnidaria
Tentacles of Sea Anemone
More Cnidarians
Brain Coral
Red jellyfish
Phyla Cnidarians or
coelenterate
Cnidaria comes from the
Greek work cnidos
meaning stinging
gastrovascular cavity
• Cnidarians are made up
of two tissue layers
separated by mesoglea.
• The ectoderm layer has three cell
types.
• contracting cells
• nerve cells
• cnidocytes (which contain
nematocysts)
http://video.nationalg
eographic.com/videobarbs
/player/animals/inver
tebratesanimals/otherinvertebrates/plankto
discharged
nematocyst
coiled
nematocyst
mouth
mesoglea
tentacle
oral arms
• Cnidarians have two body forms.
5.polyps
In the polyp
form
of a coral, the
tentacles
and mouth face
upward.
• 6. medusas
In the medusa
form of a jellyfish,
the tentacles and
mouth face
downward.
1. mouth
3. tentacle
5. ectoderm
(epidermis)
6. mesoderm
(mesoglea
7. endodrem
(gastrodermis
8. gastrovascular cavi
11. bud
12. stalk
13. basal disk
nematoc
ytes
filament
trigger
c
Barb
b
cnidocyte a
charged
Discharged
• The four major cnidarian classes are
defined by their dominant body form.
1. Anthozoans such as sea
anemones have a dominant
polyp stage.
2. Scyphozoans are true
jellyfish with a dominant
medusa form.
3. Cubozoans such as box
jellies and sea wasps have a
dominant medusa form
4. Hydrozoans such as hydra
alternate between forms.
.
• Anthozoans
• sea anemones and corals
• dominant polyp stage.
Scyphozoa
• Most familiar
• Common jellies
• Range in size
from 5
millimeters to
several meters
cubozoa
• Complex
eyes
• Swim very
quickly
• Four
tenticles
• Hydrozoans
• alternate between forms.
• Most never have a medusa stage
http://video.nationalgeographic.com/video/player/animals/invertebratesanimals/other-invertebrates/manowar_portuguese.html
Complex eyes
Polyp reduced or lost
Medusa produced by lateral bud
Radial symmetry and cnidocytes
Life cycle of the cnidarian
• Asexual reproductionBudding –
– a bud will form on the
side
–Break off and form a new
polyp
• Sexual
–Male and female medusa