ANIMAL KINGDOM. Main Characteristics Multicellular eukaryotes Heterotrophs Specialized cells; most...
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Transcript of ANIMAL KINGDOM. Main Characteristics Multicellular eukaryotes Heterotrophs Specialized cells; most...
Main CharacteristicsMain Characteristics
Multicellular eukaryotesMulticellular eukaryotes
HeterotrophsHeterotrophs
Specialized cells; most have tissuesSpecialized cells; most have tissues
Response to stimuli by nervous and Response to stimuli by nervous and muscular tissuemuscular tissue
Most capable of locomotion; few sessileMost capable of locomotion; few sessile
Most diploid and reproduce sexuallyMost diploid and reproduce sexually
Animals live in diverse habitatsAnimals live in diverse habitats
MarineMarine– Origin of animal lifeOrigin of animal life– Provides buouyancyProvides buouyancy– Body fluids isotonic to environmentBody fluids isotonic to environment– Plankton, nekton, sessilePlankton, nekton, sessile
FreshwaterFreshwater– Requires osmoregulationRequires osmoregulation– More challenging than marine: food, oxygen, More challenging than marine: food, oxygen,
sunlight, temperaturesunlight, temperature
Terrestrial – avoid dessication:Terrestrial – avoid dessication:
– Body covering to reduce Body covering to reduce evaporationevaporation
– Respiratory organs deep in body Respiratory organs deep in body cavitycavity
– ReproductionReproductionReturn to waterReturn to waterInternal fertilizationInternal fertilization
– Eggs with coveringsEggs with coverings
– Means of thermoregulationMeans of thermoregulation
Evolution of AnimalsEvolution of Animals
All animals have a common protist All animals have a common protist ancestor: choanoflagellateancestor: choanoflagellate– Cells of colony became specializedCells of colony became specialized– Division of labor resulted in single organismDivision of labor resulted in single organism
Diversity results from changes in Diversity results from changes in development that lead to changes in body development that lead to changes in body plansplans– Hox genes control early developmentHox genes control early development
Animals can be Classified Animals can be Classified According to Body SymmetryAccording to Body Symmetry
Asymmetry Asymmetry – no regular arrangementno regular arrangement
Radial symmetry Radial symmetry – similar structures arranged around central axissimilar structures arranged around central axis
Bilateral symmetry Bilateral symmetry – can only be divided through one plane (midline) can only be divided through one plane (midline) – get roughly = left and right halvesget roughly = left and right halves
CephalizationCephalization
Found in bilaterally symmetrical organismsFound in bilaterally symmetrical organisms
Concentration of sensory structures in a Concentration of sensory structures in a head head – Nerve cells concentrate in head Nerve cells concentrate in head brain brain– Nerve cord extends toward rearNerve cord extends toward rear
Bilateral symmetry and cephalization are Bilateral symmetry and cephalization are adaptations to locomotionadaptations to locomotion
Embryonic DevelopmentEmbryonic Development
ZygoteZygote formed through fertilization formed through fertilization
Undergoes Undergoes cleavagecleavage – series of mitotic – series of mitotic divisiondivision
Develops into Develops into blastulablastula – hollow ball of cells – hollow ball of cells
Undergoes Undergoes gastrulationgastrulation – formation of – formation of specific layers of tissue called germ layersspecific layers of tissue called germ layers
2 Types of Cleavage Patterns2 Types of Cleavage Patterns
RadialRadial– Parallel or right Parallel or right
angles to axisangles to axis– Fate of cell comes Fate of cell comes
laterlater– IndeterminateIndeterminate
SpiralSpiral– Diagonal to axisDiagonal to axis– Fate of cell fixed Fate of cell fixed
earlyearly– DeterminateDeterminate
Germ LayersGerm Layers
Form in all animals except spongesForm in all animals except sponges
3 layers:3 layers:– Ectoderm – outer layerEctoderm – outer layer
– Endoderm – inner layerEndoderm – inner layer
– Mesoderm – middle layerMesoderm – middle layer
DIPLOBLASTIC
TRIPLOBLASTIC
Overview of Animal typesOverview of Animal types
Sponges – loose arrangement of different Sponges – loose arrangement of different types of cells; do not have tissuestypes of cells; do not have tissues
DiploblasticDiploblastic – Cnidarians andCnidarians and CtenophoresCtenophores– Only have 2 germ layers – endo and Only have 2 germ layers – endo and
ectodermectoderm
TriploblasticTriploblastic– Have 3Have 3rdrd germ layer - mesoderm germ layer - mesoderm
Body CavityBody Cavity
Triploblastic organisms further Triploblastic organisms further grouped base on presence grouped base on presence and type of and type of coelomcoelom – fluid- – fluid-
filled cavity between digestive filled cavity between digestive tract and body walltract and body wall
Body Cavity ClassificationBody Cavity Classification
AcoelomatesAcoelomates– Solid body; no cavitySolid body; no cavity– Flatworms and ribbon wormsFlatworms and ribbon worms
PseudocoelomatesPseudocoelomates– Have a body cavity but it is Have a body cavity but it is
not completely lined with not completely lined with mesodermmesoderm
– Nematodes and rotifersNematodes and rotifers
CoelomatesCoelomates– Tube-within-a-tube body Tube-within-a-tube body
planplan– Coelom completely lined Coelom completely lined
with mesodermwith mesoderm
Comparison
2 main groups of bilateral animals:2 main groups of bilateral animals:
During gastrulation, group of During gastrulation, group of cells move in forming sac … cells move in forming sac … embryonic gutembryonic gut
If blastopore becomes mouth – If blastopore becomes mouth – organism is a organism is a protostomeprotostome
If blastopores becomes anus - If blastopores becomes anus - deuterostomedeuterostome
Protostomes vs. Deuterostomes Protostomes vs. Deuterostomes
PROTOSTOMESPROTOSTOMES
Flatworms, annelids, Flatworms, annelids, arthropods, mollusksarthropods, mollusks
SPIRAL CLEAVAGESPIRAL CLEAVAGE
Developmental fate of Developmental fate of embryo fixed early = embryo fixed early = determinatedeterminate
DEUTEROSTOMESDEUTEROSTOMES
Echinoderms and Echinoderms and chordateschordates
RADIAL CLEAVAGERADIAL CLEAVAGE
Fate of embryo occurs Fate of embryo occurs later = indeterminate later = indeterminate