Download Introduction to Animals - Phillips Scientific Methods

Introduction to Animals- STUDY GUIDE
General Characteristics
All are multicellular, eukaryotic, and heterotrophic
Cells lack cell walls & come in a variety of shapes
Ingestive heterotrophs (take in food & internally digest it)
Store food reserves temporarily as glycogen in the liver
Have some type of skeletal support
Exoskeletons found in arthropods cover the outside of the body but limit size
Endoskeletons found in all vertebrates are found inside the body & are made of
cartilage &/or bone
Worms have fluid-filled internal cavities giving them skeletal support (hydrostatic)
Sponges have the simplest skeleton
May be sessile (attached & non-moving) or motile (larvae are motile)-Ex: sponge
(Porifera)
Reproduce sexually (some can still reproduce asexually)
Show levels of organization including cell, tissue, organ, & system, as animals
evolved
Cells are specialized for particular functions (differentiation)
Cell junctions hold individual cells in a tissue together
Most vertebrates have a backbone or spine made of repeating bones called vertebrae
that protect the spinal cord
Some show cephalization (have a head with sensory organs concentrated there)
Those with bilateral symmetry have dorsal, ventral, anterior, posterior (*usually refers
to quadrupeds, such as a dog)
Invertebrate Groups
Simplest animals
Contains the greatest number of animal species
Most found in water
Do not have a backbone
Some have different adult forms- Ex: polyp and medusa in Cnidarians
Includes sponges, cnidarians, flatworms, roundworms, annelids (segmented worms),
mollusks, arthropods, & echinoderms
Vertebrate Groups (Subphylum of Chordata)
More complex animals
Most have a backbone
Includes fish, amphibians, reptiles, birds, & mammals
Body Areas
Dorsal is the back or upper surface
Ventral is the belly or lower surface
Anterior head or front end
Posterior is the tail or hind end opposite the head
Oral surface in echinoderms is where the mouth is located (underside)
Aboral surface in echinoderms is the surface opposite the mouth (top side)
DORSAL
VENTRAL
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)
Radial symmetry occurs when similar body parts are arranged around a central point
like spokes on a wheel (Echinoderms. ex- starfish)
Most animals with radial symmetry are sessile (attached) or sedentary (move very
little)
Bilateral symmetry occurs when animals can be divided into equal halves along a
single plane (right & left sides that are mirror images)
Animals with bilateral symmetry are more complex, usually motile organisms, such as
worms, arthropods, and all vertebrates
Animals with bilateral symmetry show cephalization & have anterior & posterior ends
Segmentation
Occurs whenever animal bodies are divided into repeating units or segments
Found in more complex animals
Earthworms show external segmentation, while humans show internal segmentation
(vertebrae of the backbone)
Segments may be fused together such as cephalothorax covering chest & head of a
crayfish, while some have head, thorax, abdomen- insects (both are arthropods, which
has the largest # of species)
Tissue Development
All animals reproduce sexually, but some also reproduce asexually (sponges bud &
flatworms fragment)
Zygote is the fertilized egg all animals form from
Zygote undergoes rapid cell divisions known as cleavage to become hollow ball of
cells called blastula
Blastocoel is the central hollow cavity of the blastula
Blastula invaginates (folds inward at one point) to form an opening & formation of
germ layers begins; process called gastrulation
Inner germ layer called endoderm & outer germ layer called ectoderm. Some have a
3 layer called mesoderm. *What do these germ layers give rise to? (See PPt!)
rd
Opening (blastopore) may become the mouth or the anus
Protostomes (mollusks, arthropods, & annelids) develop mouth from blastopore, while
deuterostomes (echinoderms & vertebrates) develop an anus from blastopore
Cells differentiation during development changes their shapes (structure) to fit their
function (neurons or nerve cells become long to conduct messages)
Cleavage – OMIT IN 2017
Protostomes have spiral cleavage in which embryonic cells divide in a spiral
arrangement
Deuterostomes have radial cleavage or embryonic cell division parallel or
perpendicular to the vertical axis of the embryo
Protostomes have determinate cleavage (embryonic cells can't form a new organism if
separated)
Deuterostomes have indeterminate cleavage (embryonic cells can form other
organisms if separated such as identical twins)
Germ Layers
Form the tissues, organs, & systems of an animal
Found in the embryo of all animals except sponges (have specialized cells but no
tissues)
Ectoderm (outer) forms skin, nerves, & sense organs
Endoderm (inner) forms the digestive tract & respiratory organs & systems
Mesoderm (middle) forms muscles, bone, circulatory system, reproductive &
excretory systems
Larval Forms- OMIT IN 2017
Some animals have indirect development & go through an immature larval form that
does not resemble the adult
Planula is the larva of cnidarians (jellyfish, corals, & sea anemones)
Trochophore is the larva of mollusks (squid & octopus)
Dipleurula is the larva of echinoderms (starfish & sea urchins)
Metamorphosis
May be complete or incomplete
Usually found in arthropods
Incomplete metamorphosis (egg --> nymph --> adult) Ex- grasshopper
Complete metamorphosis ( egg --> larva --> pupa --> adult) Ex- butterfly, moth
*Metamorphosis also occurs in amphibians. Why?
Body Cavities
Coelom is an internal body cavity lined with mesoderm
Animals with a true coelom are called coelomate animals (annelids, mollusks,
arthropods, & vertebrates)
Acoelomate animals do not have a body cavity but have ‘solid’ bodies (no mesoderm,
instead has mesoglea. Ex: sponges, flatworms, & cnidarians
Pseudocoelomate animals have a body cavity only partially lined with mesoderm
(roundworms)
Body Layers
Sponges have specialized cells but no tissues or organs
Cnidarians (jellyfish, coral, sea anemone) have 2 body layers (ectoderm & endoderm)
with a jellylike layer called mesoglea between for support
Cnidarians have one body opening into a large cavity called gastrovascular cavity
All worms, mollusks, arthropods, echinoderms, & vertebrates have 3 cell layers
(ectoderm, mesoderm, & endoderm)
Mouth & Anus Development
Blastopore is the opening in the gastrula formed when blastula folds inward
Protostomes are animals that the blastopore develops into the mouth (earthworms,
mollusks, arthropods)
Deuterostomes are animals that the blastopore develops into the anus (echinoderms &
chordates)
Support Systems
Sponges are supported by spicules (made of various substances), while limestone
cases support corals
Hydrostatic skeletons in worms consist of a fluid-filled body cavity surrounded by
muscles. Another exp: jellyfish
Arthropods have external exoskeletons that prevent water loss but must be molted for
growth to occur
Echinoderms & vertebrates have internal endoskeletons that grow with the organism
Digestive Systems
All animals are heterotrophs
Sponges have specialized cells to capture, digest and circulate their food
Cnidarians have one opening into their gastrovascular cavity where food enters &
wastes leave; called a two-way digestive system. Also, flatworms (ex- planaria) have this
Annelids, arthropods, & vertebrates have a one-way digestive system in which food
enters the mouth, is digested & wastes leave through the anus
Circulatory System
Transports oxygen and nutrients to cells & carbon dioxide and wastes away from cells
Sponges, cnidarians, & flatworms don't have a circulatory system (diffusion)
In closed systems, blood remains in blood vessels at all times until it reaches cells
(earthworms & vertebrates)
In open systems, blood isn't always contained in blood vessels (arthropods). Blood
directly bathes the organs and then is collected in another vessel
Respiratory System
Oxygen is needed for cellular respiration & carbon dioxide must be eliminated
Sponges, cnidarians, flatworms, & roundworms exchange gases by diffusion
Mollusks & fish use gills to exchanges gases, while terrestrial vertebrates use lungs
Nervous System
Cephalization occurs in animals that have a distinct head at the anterior end where
sensory organs are concentrated
Cephalization is found in more complex animals
Sponges have specialized nerve cells, while cnidarians & flatworms have a nerve net
Ganglia are clusters of nerve cells found in more complex animals
Nerve cells may specialize to detect, light, sound, etc. (ex- planaria worms have
eyespots.
Animals with a brain interpret nerve impulses & sends a response
Body Coverings
Integument is the outer covering of an animal
Terrestrial vertebrates have water-tight outer coverings
Integuments of amphibians allow some gas exchange through the skin (small lungs)
Adaptations of integuments include scales, fur, hair, & feathers to protect and insulate
the body
Excretory System
Rid animals of wastes, help conserve water, & filter wastes from the blood
Ammonia is a toxic waste that must be gotten rid of by an animal's body. Closely
related forms of ammonia excreted by some animals: urea, uric acid
Kidneys: used to filter blood in vertebrates
Reproductive System
All animals reproduce sexually, but some also use asexual reproduction
Budding is asexual reproduction in which an outgrowth on the parent organism breaks
off to form a new individual. Ex- hydra (a cnidarian)
Sponges, flatworms, & cnidarians asexually reproduce by fragmentation (separating
into pieces & each piece making a new organism)
Some insects develop from unfertilized eggs by a process known as parthenogenesis
Hermaphrodites are animals that produce both sperm & eggs. Ex: earthworms – crossfertilize with each other (exchange sperm) & tapeworms can self-fertilize in their body
sections called proglottids
Echinoderms, arthropods, mollusks, & vertebrates have separate sexes (sperm to egg)
Internal fertilization occurs inside the body of the female & larger numbers of sperm
& eggs are produced
External fertilization occurs inside the body of the female. Ex- Frogs. If fertilization
and development is successful in the water, tadpoles result.
BE SURE AND STUDY VERTEBRATE ‘BASIC’ CHARACTERISTICS.
KNOW THE FOLLOWING EVOLUTIONARY CHARACTERISTICS AND TO
WHICH CLASSES THEY APPLY: (The following are not necessarily in evolutionary
‘order’ and some apply to more than 1 class)
1- Jawless fish
2- Fish with jaws
3- Class that transitioned from water to land
4- Amniotic egg
5- cartilage skeleton (fish)
6- bony skeleton (fish)
7- ectothermic
8- endothermic
9- bones not filled with marrow (hollow)
10- Hair, mammary glands, give birth to live young
MAMMALIAN CLASSIFICATION: (know basic characteristics and examples)
1. Monotremes
2. Marsupials
3. Placentals
a. Placental Order: Primates. Basic Characteristics?
Know these terms: viviparous, oviparous, ovoviviparous
GO OVER: 1) INTRO TO ANIMALS PPT; 2) INVERTERATE PPT AND THE 3)
VERTEBRATE PPT
GO OVER ANIMAL BEHAVIOR PPT! Be sure to know: ethology, innate, imprinting,
classical conditioning, altruism, territorial behaviors, sexual selection/mating behaviors,
pheromones