Transcript VI. PHYLUM CHORDATA - Subphylum Vertebrata

UNIT X – KINGDOM ANIMALIA
Big Campbell – Ch 32 - 34, 40, 44, 46, 53 - 55
Baby Campbell – Ch 18, 20, 25, 27, 36, 37
I. ORIGINS OF KINGDOM ANIMALIA
I. ORIGINS OF KINGDOM ANIMALIA, cont
II. INTRODUCTION TO KINGDOM ANIMALIA
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• Bodies held together with structural proteins
 Collagen
• Regulatory genes
 Hox genes
• Reproduce sexually
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II. INTRODUCTION TO KINGDOM ANIMALIA, cont
Embryonic Development
In Animals
III. CLASSIFICATION OF ANIMALS
• Based on . . .
A. Presence or absence of true tissues
B. Symmetry
C. Development of germ layers
D. Presence of body cavity
E. Embryonic development
A. Tissues
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Metazoa (Parazoa) – organisms without true tissues
Eumetazoa – organisms with true tissues
III. CLASSIFICATION OF ANIMALS, cont
B. Symmetry
• Asymmetry
• Radial
• Bilateral – cephalization
III. CLASSIFICATION OF ANIMALS, cont
C. Development of Germ Layers
Form various tissues & organs
 Ectoderm
 Mesoderm
 Endoderm
• Diploblastic Organisms
 2 layers
 No mesoderm
• Most animals are triploblastic
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III. CLASSIFICATION OF ANIMALS, cont
D. Presence of Body Cavity
• Only applies to triploblasts
• Acoelomates
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No body cavity
Solid body
Pseudocoelomates
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“False” body cavity
Not lined with mesoderm
• Coelomates
 True body cavity
 All other animals
III. CLASSIFICATION OF ANIMALS, cont
E. Embryonic Development
• Applies to organisms with
bilateral symmetry, primarily
coelomates
• Protostomes
 Spiral cleavage
 Schizocoelous
 Opening formed during
gastrulation (blastopore)
becomes mouth
 Mollusks, annelids, arthropods
• Deuterostomes
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Radial cleavage
Enterocoelous
Blastopore develops into anus
Echinoderms, chordates
III. CLASSIFICATION OF ANIMALS, cont
IV. INVERTEBRATES
• Make up 95% of all
animals
• Most scientists
agree on
approximately 35
animal phyla
• 34 of these are
made up of
invertebrates
V. PHYLUM CHORDATA
Clip
V. PHYLUM CHORDATA, cont
V. PHYLUM CHORDATA, cont
• Four characteristics common
to all chordate embryos
– Notochord – Flexible rod located
between digestive tract & nerve
cord
– Dorsal Hollow Nerve Cord –
Eventually develops into brain and
spinal cord
– Pharyngeal Slits – Present in
developmental stages; may not be
found in adult stage
– Post-anal Tail
• Divided into 3 sub-phyla:
– Urochordata
– Cephalochordata
– Vertebrata
V. PHYLUM CHORDATA, cont
Invertebrate
Chordates
• Lack a true backbone
• Suspension feeders
• Closest vertebrate
relatives; appear 50
million years prior to
vertebrates
• Subphylum
Urochordata
– Tunicates, sea squirts
– Sessile as adults
• Subphylum
Cephalochordata
– Lancelets, amphioxus
– Burrow in sand of ocean
floor
VI. PHYLUM CHORDATA - Subphylum Vertebrata
• Notochord secretes proteins that make up somites – differentiate into vertebrae,
ribs, skeletal muscles of trunk
• Pronounced cephalization
• Closed circulatory system with chambered heart
VI. PHYLUM CHORDATA - Subphylum Vertebrata
Class Agnatha
• Jawless vertebrates
• Most primitive, living
vertebrates
• Lack paired appendages
• Cartilaginous skeleton
• Notochord present throughout
life
• Rasping mouth
• 2-chambered heart
• Hagfish – no longer
considered to be vertebrates
by some taxonomists;
scavengers
• Lampreys – usually parasitic
VI. PHYLUM CHORDATA - Subphylum Vertebrata
Class Chondrichthyes
• Cartilaginous fishes
• Sharks, skates, rays
• Well-developed jaws; paired fins
• Continual water flow over gills
• Lateral line system (water pressure changes)
• Internal Fertilization; may be
– Oviparous- eggs hatch outside mother’s body
– Ovoviviparous- retain fertilized eggs; nourished by egg yolk; young born live
VI. PHYLUM CHORDATA - Subphylum Vertebrata
Class Osteichthyes
• Ossified endoskeleton
• Scales
• Operculum
• Swim bladder
• Ectotherms
• Most numerous of all vertebrates
• Ray-fined – Most common type; fins supported by long, bony rods arranged in a ray
pattern; bass, trout, perch, tuna, herring
• Lobe-finned - Fins supported by rod-shaped bones surrounded by a thick layer of muscle;
coelocanth; lungfishes
VI. PHYLUM CHORDATA - Subphylum Vertebrata
Class Amphibia
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First tetrapods, land animals
Frogs, toads, salamanders
Metamorphosis
Ectotherms
External fertilization; lack shelled egg
Moist skin for gas exchange
2 → 3 chambered heart
VI. PHYLUM CHORDATA - Subphylum Vertebrata
Class Reptilia
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Lizards, snakes, turtles, and crocodilians
Internal fertilization
Amniotes – Eggs have shells, extraembryonic membranes which aid in gas exchange, transfer of
nutrients, protection
Ectotherms
3-chambered heart in most; 4-chambered heart in crocs
Scales with keratin
VI. PHYLUM CHORDATA - Subphylum Vertebrata
“Class Aves”
• Have many adaptations for flight
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Wings
Honeycombed bone
Feathers (keratin)
Toothless
Lack urinary bladder
One ovary
Large breastbone
• Endothermic
• 4-chambered Heart
• Fossil studies show connection
between reptiles and birds; birds
now included in Class Reptilia
• Archaeopteryx – earliest known
bird
VI. PHYLUM CHORDATA - Subphylum Vertebrata
Class Mammalia
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Mammary glands
Hair (keratin)
Endothermic
4-chambered heart
Large brains (relative to size)
Teeth differentiation
Diaphragm
Divided into three groups
– Monotremes – Egg-layers;
platypus, anteaters
– Marsupials – Embryonic
development of young completed in
pouch; kangaroos, koalas,
opossums
– Eutherians – Placental mammals;
all other mammals
VII. ANIMAL FORM & FUNCTION
• Anatomy vs Physiology
• Humans are composed of
4 tissue types
 Epithelial
 Connective
 Nerve
 Muscle
VII. ANIMAL FORM & FUNCTION, cont
Epithelial Tissue
• Covers body and lines organs and
cavities
• Forms glands
• May secrete mucus, be ciliated
• Held together by tight junctions
• Basement membrane
 Anchors one side of epithelium to
tissues beneath
 Extracellular matrix made up of
protein, polysaccharides
• Classified according to the number
of layers of cells
 Simple - single layer of cells
 Stratified – multiple layers
• And the shape of the cells
 Squamous
 Cuboidal
 Columnar
VII. ANIMAL FORM & FUNCTION, cont
Connective Tissue
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Bind and support other tissues
Consists of cells loosely organized in an extracellular matrix
Matrix is produced and secreted by cells
VII. ANIMAL FORM & FUNCTION, cont
Nerve Tissue
• Senses stimuli and transmits
signals from 1 part of the animal
to another
• Neuron
 Dendrites
 Cell Body
 Axon
VII. ANIMAL FORM & FUNCTION, cont
Muscle Tissue
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Capable of contracting when
stimulated by nerve impulses
Myofibrils composed of
proteins, actin and myosin
3 Types of Muscle Tissue
 Skeletal – Voluntary,
striated
 Cardiac – Involuntary,
striated, branched;
makes direct contact with
other cardiac muscle
cells
 Smooth – Involuntary;
lacks striations
VIII. REGULATION OF INTERNAL ENVIRONMENT
• Fluid that surrounds cells is
known as interstitial fluid
• Temperature, water
concentration, salt
concentration, pH must be kept
relatively constant to maintain
homeostasis
• Maintained through
 Negative Feedback – Triggers
response that counteracts the
change
 Positive Feedback – Triggers
response that amplify the
change
VIII. INTERNAL ENVIRONMENT REGULATION, cont
Osmoregulation
• Management of the body’s water content and solute composition
• Animals may be classified as:
Osmoconformer: Marine invertebrates. Solute concentration
in sea equal to that of organism; therefore, no active
adjustment of internal osmolarity (marine animals); isoosmotic
to environment
Osmoregulator: Include marine vertebrates, freshwater
animals, land animals. Body fluids have solute concentration
different from environment. Must expend energy to regulate
water loss or gain.
VIII. INTERNAL ENVIRONMENT REGULATION, cont
Osmoregulation, cont
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Freshwater fishes
 Higher solute
concentration in fish →
fish gains water, loses
salt → doesn’t drink
water, excretes large
amounts of dilute urine
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Marine fishes
 Lower solute
concentration in fish →
fish loses water, gains
salt → drinks large
amount of saltwater,
pumps excess salt out
of gills, produces small
amounts of urine
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VIII. INTERNAL ENVIRONMENT REGULATION, cont
Thermoregulation
Regulation of body temperature
Four physical processes:
 Conduction - Transfer of heat between
objects in direct contact
 Convection - Transfer of heat by
movement of air/liquid past a surface
 Radiation - Transfer of heat between
objects not in direct contact
 Evaporation - Loss of heat in conversion
of liquid to gas
Sources of body heat:
 Ectothermic - Determined by environment
 Endothermic - High metabolic rate
generates high body heat
Countercurrent Heat Exchangers
 Two types of blood vessels arranged in
anti-parallel fashion
VIII. INTERNAL ENVIRONMENT REGULATION, cont
Thermoregulation, cont.
• Adaptations
o Torpor - Low activity; decrease in
metabolic rate
 Hibernation
 Long-term or winter torpor
 Due to winter cold, food
scarcity
 Bears, squirrels
 Estivation
 Short-term or summer torpor
 Adaptation for high
temperatures, water scarcity
 Fish, amphibians, reptiles
 Both typically triggered by length of
daylight
VIII. INTERNAL ENVIRONMENT REGULATION, cont
Thermoregulation, cont.
Human Thermoregulation
VIII. INTERNAL ENVIRONMENT REGULATION, cont
Metabolism
• Sum of all energyrequiring biochemical
reactions
• Energy measured in
Joules, calories, or
kilocalories (Calories)
• Metabolic rate may be
determined by
 Monitoring rate of heat
loss
 Measuring amount of O2
consumed or CO2
produced
IX. ANIMAL REPRODUCTION
IX. ANIMAL REPRODUCTION
Asexual
• Fission (parent separation)
• Budding (sponges, corals)
• Fragmentation +
Regeneration (inverts)
Sexual
• Gametes
 Ovum
 Sperm
• Zygote
IX. ANIMAL REPRODUCTION
Mechanisms of Reproduction
• Parthenogenesis
 Unfertilized egg
development
 Typically haploid,
sterile adults
 Daphnia, Rotifers,
honeybees
IX. ANIMAL REPRODUCTION
Mechanisms of Reproduction, cont
• Hermaphroditism
 Both male & female reproductive systems
 Occurs in earthworms, other sessile & burrowing organisms
IX. ANIMAL REPRODUCTION
Mechanisms of Reproduction, cont
• Sequential
hermaphroditism
 Reversal of gender
during lifetime
 Protogynous - female first
 Protandrous – male first
IX. ANIMAL REPRODUCTION
Sexual Reproduction
• Pheromes
 Chemical signals released by
organism
 Influences behavior, physiology of
organisms of same species
 Active in minute amounts
• Fertilization
 External
 Internal
X. ECOLOGY
Interactions Between Organisms & Their Environment
X. ECOLOGY
Important Terms/Concepts
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Levels of Organization
 Organism → Species → Population →
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Biomes
Food Chains
 Trophic levels
 Importance, examples of decomposers
 Comparison of energy flow vs recycling
of nutrients
 Most energy?
 Pyramid of production
 Limits on trophic levels
 Primary production provides the “energy
budget” for any given ecosystem
• Niche
X. ECOLOGY
Nutrient Cycles
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Water
Carbon
Phosphorus
Nitrogen
X. ECOLOGY
Ecological Succession
• Changes seen in a community following a severe disturbance
 Primary Succession
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Describes individuals colonizing virtually lifeless area with no soil; may be due to volcano, glacier
Typically begins with autotrophic bacteria; followed by lichens, mosses
Known as pioneer organisms
Gradual development of soil due to weather, decomposition of pioneer organisms
Larger organisms begin to inhabit area → eventually results in climax community
 Secondary Succession
 Results from disturbance that leaves soil intact; for example, fire
X. ECOLOGY
Population Ecology
• Study of how and why
populations change
• Survivorship Curves
 Type I – have few young but
provide good care; seen in
humans & other large mammals
 Type II – intermediate; mortality
fairly constant over life span;
seen in some invertebrates,
lizards, rodents
 Type III – high death rates for
very young; typically produce
high number of young but
provide very little care; seen in
fish, amphibians, some
invertebrates
X. ECOLOGY
Population Ecology, cont
• Exponential Growth
 Occurs when population is in
ideal environment
 No limiting factors
 Entire population multiplies by a
constant factor
• Logistic Growth
 Population impacted by limiting
factors
 Carrying Capacity is met
 Limiting factors may be
described as
 Density-Dependent
 Density-Independent
X. ECOLOGY
Population Ecology, cont
• Life history traits include reproductive age, frequency of reproduction, number of
offspring, amount of parental care
• Shaped by evolution and natural selection
• Selection for life history strategies determined by population densities and
conditions
 r-selection
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Seen in uncrowded, unpredictable environments
Also known as density-independent selection
Individuals mature early and/or produce maximum number of offspring at one time
Maximizes r, the per capita rate of increase
Bacteria, weeds
 K-selection
 Typically seen in larger, longer-lived individuals
 Population is close to carrying capacity therefore competitive ability, efficient use of resources
favored
 Maturity & reproduction at later age
 Fewer young; higher degree of parental care
 Term, K refers to carrying capacity
X. ECOLOGY
Population Ecology, cont
Human Population Growth . . .
Exponential . . .
but, it is slowing