Download Introduction to animals

Introduction to animals
Introduction to
Animals – Ch. 32
The Nature of Animals
Section 32.1
Classification:
● 95-98% of animals are invertebrates
● Without a backbone
● 2-5% of animals are vertebrates
● With a backbone
Animal
Traits
Characteristics:
1.
2.
3.
4.
5.
6.
All animals are:
Multicellular
Eukaryotic
Ingestive heterotrophs
Lacking in cell walls
Sexually reproductive
Able to move
1. Multicellular Organization
● Cell specialization: the evolutionary
adaptation of a cell for a particular function
● Tissue: group of similar cells that perform
a common function
● Cell junctions: connections between cells
that hold them together as a unit
Atom
Molecule
or
compound
Levels of Organization
Organ
Tissue
Organ
system
Organelle
CELL
Life begins
Organism
2. Eukaryotic cells
3. Ingestive Heterotrophy
● Getting complex organic compounds
(carbon) from sources other than the sun
● Ingestion: taking in food usually in the
form of an other organism
● Digestion: the body’s process of
extracting organic molecules from food
Lions Feeding (Ingestion)
4. Lack of cell walls
5. Sexual Reproduction & Development
● Hermaphrodites: producing both eggs and
sperm
● Examples: worms & sponges
● Most do NOT fertilize own eggs
● Why not?
● Zygote: diploid cell that results from the fusion
of two haploid gametes
● Undergoes differentiation (cells becoming
specialized to perform a specific function)
Female
Beetles
Mating
Courtship
Young
Male
Mating and
Mating
Behaviors
Leeches Exchange Sperm During
Mating
leech
Mating
Parthenogenesis:
● Females of some animals produce eggs,
but the eggs develop without being
fertilized!
● New offspring will be all female
● Example animals: some fishes, several
kinds of insects, and a few species of
frogs and lizards
Parthenogenesis in the Komodo Dragon
Video
6. Movement
● Sessile: attached & non-moving
● sponges
● Sedentary: move very little
● clam
● Motile: animals that can move
● humans
● Ability to move depends upon interaction between
nervous tissue and muscle tissues
● Neurons: cells of nervous tissue
SESSILE
Sponge
SEDENTARY
Chiton
MOTILE
Cheetah
Origin of Animals:
● Animals came about in the water
● Evolved from colonial protists:
● Each organism had its own function (for the
colony) much like each cell of the animal body
has its own function (for the organism)
Vide
o
Body Structure:
● 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
Radial symmetry
● when body parts are arranged around a
central point
● like spokes on a wheel
● echinoderms
● Most animals are sessile (attached) or
sedentary (move very little)
Bilateral symmetry
● when animals can be divided into equal
halves along a single plane
● right and left sides that are mirror
images of each other
● are usually motile
● Show cephalization
● concentration of sensory organs on
the head (anterior) end
What type of symmetry is this?
Segmentation
● When an animal body is composed of a series of
repeating similar units
● Example: earthworm (annelid)
● Segments may look different & have different
functions
● Example: insects & crustaceans (arthropods)
Anatomical Terms:
Dorsal: back surface of animal
Ventral: underside of animal
Anterior: front end of animal
Posterior: rear end of animal
Lateral: sides of animal
Medial: along midline of animal
Proximal: near to
Distal: away from
Label the parts:
Comparison of
Invertebrates & Vertebrates
Section 32.2
Invertebrate
groups
Video
Invertebrates
● Simplest animals
● Contain the greatest number of different species
● Most are aquatic
● Do NOT have a backbone
● Includes:
●
sponges, cnidarians, flatworms,
roundworms, annelids, mollusks, arthropods,
& echinoderms
Sponges – Phylum Porifera
Osculum
of
Sponge
Sea Anemone – Phylum Cnidaria
Tentacles of Sea Anemone
More Phylum Cnidaria
Brain Coral
Red jellyfish
*
Flatworms – Phylum Platyhelminthes
Marine Flatworm
Planarian
Roundworms - Phylum Nematoda
Segmented Worms – Phylum Annelida
Nematode
Leech (segmented worm)
Phylum Mollusca (With and Without Shells)
snail
nautilus
scallop
nudibranch
octopus
Phylum Arthropoda
spider
crayfish
Horseshoe crab
Dung
beetle
Phylum Echinodermata
Sea fan (crinoid)
starfish
Brittle star
Sand dollar
Sea cucumber
Symmetry
● Most are radial or bilateral
● Radial can receive stimuli and move in any
direction (in water)
Bilateral but NOT an
invertebrate
● Some are highly cephalized
Radia
l
Bilatera
l
Support of the Body
● Various types of support:
1. Simple skeletons (sponges)
2. Fluid-filled body cavity (roundworms)
3. Exoskeleton (crayfish)
● Rigid outer covering for protection of soft
tissue
2 Types of Circulatory Systems:
● Open circulatory system: circulatory fluid is
pumped by the heart through vessels into a body
cavity
● Arthropods & most mollusks
● Closed circulatory system: circulatory fluid is
restricted to vessels in a closed loop
● Squid (mollusk)
VIDEO
Digestive & Excretory Systems
● Gut: a digestive tract running through the body
● Liquid wastes are excreted as ammonia
● highly toxic
Development
●
●Indirect Development: an
intermediate larval stage occurs
● Flies
● Direct development: young animal
appears similar to adult
● grasshoppers
Indirect
Developme
nt
Vertebrate
Groups
Video!
Fishes – Classes Myxini, Cephalaspidomorphi, Chondrichthyes,
Actinopterygii, and Sarcopterygii
lancelet
ray
damselfish
anglerfish
salamander
Class Amphibia
toad
frog
newt
Class Reptilia
Turtle
Snake
Lizard
Alligator
Class Aves
hummingbird
ostrich
lovebirds
Class Mammalia
Vertebrata
● More complex animals
● Most have a backbone made up of individual
bones called vertebrae
● All species are in the Phylum Chordata
● From simplest to most complex groups:
● Fish
● Amphibians
● Reptiles
● Birds
● Mammals
Support of Body
● Vertebrates have endoskeletons
● Internal skeletons
● Supports more weight
● Grows as animal grows (no molting)
● Some vertebrates have skeletons of cartilage
● sharks, rays, and skates
● Other vertebrates have skeletons of bone and cartilage
● reptiles, birds, & mammals
Bone & Cartilage in Fetus
Segmentation
● Vertebrae: repeating bony units of the backbone
● Vertebrae & ribs are segmented
Body Covering
● Integument: outer covering of an animal
● Terrestrial animals are water-tight
●
Why?
● Examples: feathers, hair, scales
Respiration & Circulation
● Respiration (breathing):
● Aquatic = gills
● Terrestrial = lungs
● Circulation:
● Closed circulation with multi-chambered heart
●
●
Separates oxygen and deoxygenated blood
Improves efficiency
Digestion & Excretion
● Digestion:
● Occurs in the gut (mouth → anus)
● Excretion:
● Kidneys: filters wastes from the blood while regulates
water levels in the body
Nervous System
● Highly organized brains
● Each part has its own function
Section 32.3
Fertilization & Development
Fertilization
● Definition: the union of the female and male
reproductive gametes
● Results in a single diploid cell named the zygote
I’m in!
Fertilization Steps:
VIDEO
1.
2.
3.
4.
Sperm’s membrane fuses with egg’s membrane
Electrical charge occurs to block entry of other
sperm into egg
Sperm nucleus merges with egg nucleus forming
zygote
DNA replication begins & cell division occurs
Cleavage
● Definition: division of the zygote immediately
following fertilization via mitosis
● Organism size does not increase even though
number of cells does
VIDEO
Tissue Development
●Cleavage results in the formation of a
hollow ball of cells called the blastula
Blastula
•The blastocoel is the center cavity of the
blastula with 1 germ layer (blastoderm)
Tissue Development
● The blastula invaginates
● folds inward at one
point
● Called Gastrulation
● The opening is called the
Archenteron
blastopore
● The center is the
primitive gut
● Archenteron
blastopore
Embryonic Development
VIDEO
Tissues
Tissue Development:
● Germ layers: tissues found in the embryos
of all animals except sponges
● Typically three layers in depth
● All body features arise from one of these layers
● Body cavities: fluid-filled space that forms
between the digestive tract & outer wall of
body during development
● Aids in movement of animal
● Reservoir for transport of materials
Germ Layers
● Form tissues, organs, &
systems
● NOT present in sponges
● Ectoderm (outer) – forms
skin, nerves, sense organs
● Endoderm (inner) – forms
liver and lungs
● Mesoderm (middle) – forms
muscles & other systems
Animation
Body Cavities
Coelom = Body Cavity
●Internal body cavity fully lined with
mesoderm
● Body organs suspended in this cavity
Types of body cavities:
1. Acoelomates: no body cavity
●
●
solid bodies filled with cells
sponges, cnidarians, & flatworms
2. Pseudocoelomates: “false body cavity”
●
●
have a functional body cavity NOT fully lined
with mesoderm
Rotifer, roundworms
3. Coelomates: true coelom
●
Mollusks, annelids, arthropods, chordates
Acoelomate
●
no body cavity
●
●
solid bodies filled with cells
sponges, cnidarians, & flatworms
Pseudocoelomate
●
“false body cavity”
●
have a functional body cavity NOT fully lined with
mesoderm
Rotifer, roundworms
●
Coelmate:
●
true coelom
●
Mollusks, annelids, arthropods, chordates