Transcript Ch. 40 Warm up

Ch. 40 Warm up
1. Define and give an example of
homeostasis.
2. Sequence the organization of living things
from cell to biome.
3. Describe negative and positive feedback.
LECTURE PRESENTATIONS
For CAMPBELL BIOLOGY, NINTH EDITION
Jane B. Reece, Lisa A. Urry, Michael L. Cain, Steven A. Wasserman, Peter V. Minorsky, Robert B. Jackson
Chapter 40
Basic Principles of Animal Form
and Function
Lectures by
Erin Barley
Kathleen Fitzpatrick
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Overview: Diverse Forms, Common
Challenges
• Anatomy: the study of the biological form
(STRUCTURE) of an organism
• Physiology: the study of the biological
FUNCTIONS an organism performs
• Structure dictates function!
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Figure 40.1
Animal form and function are correlated
at all levels of organization
• Size and shape affect
the way an animal
interacts with its
environment
• Many different animal
body plans have
evolved and are
determined by the
genome
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Hierarchical Organization of Body Plans
• Cells  Tissues  Organs  Organ Systems
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Four main types of tissues:
1. Epithelial: covers the outside of the body and
lines the organs and cavities within the body
2. Connective: binds and supports other tissues
(cartilage, tendons, ligaments, bone, blood,
adipose)
3. Muscle: controls body movement (skeletal,
smooth, cardiac)
4. Nervous: senses stimuli and transmits signals
throughout the animal (neurons, glia)
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Coordination and Control Within a Body
• Endocrine system: transmits chemical signals
(hormones) to receptive cells throughout body via
blood
– Slow acting, long-lasting effects
• Nervous system: neurons transmit info between
specific locations
– Very fast!
– Info received by: neurons, muscle cells,
endocrine cells
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Homeostasis
• Maintain a “steady state” or internal balance
regardless of external environment
• Fluctuations above/below a set point serve as a
stimulus; these are detected by a sensor and
trigger a response
• The response returns the variable to the set point
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Negative Feedback
• “More gets you less.”
• Return changing
conditions back to set
point
• Examples:
– Temperature
– Blood glucose levels
– Blood pH
Plants: response to
water limitations
Positive Feedback
• “More gets you more.”
• Response moves variable
further away from set
point
• Stimulus amplifies a
response
• Examples:
– Lactation in mammals
– Onset of labor in
childbirth
Plants: ripening of fruit
Thermoregulation
• Maintain an internal temperature within a tolerable
range
• Endothermic animals generate heat by
metabolism (birds and mammals)
• Ectothermic animals gain heat from external
sources (invertebrates, fishes, amphibians, and
nonavian reptiles)
• Q: Which is more active at greater temperature
variations?
• Q: Which requires more energy?
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Figure 40.10
Balancing Heat Loss and Gain
• Organisms exchange heat by four physical
processes: radiation, evaporation, convection, and
conduction
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Five adaptations for thermoregulation:
•
•
•
•
•
Insulation (skin, feather, fur, blubber)
Circulatory adaptations (countercurrent exchange)
Cooling by evaporative heat loss (sweat)
Behavioral responses (shivering)
Adjusting metabolic heat production (“antifreeze”)
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Figure 40.12
Figure 40.16
Energy Use
• Metabolic rate: amount of energy an animal
uses in a unit of time
• Basal metabolic rate (BMR): endotherm at rest
at a “comfortable” temperature
• Standard metabolic rate (SMR): ectotherm at
rest at a specific temperature
• Ectotherms have much lower metabolic rates
than endotherms of a comparable size
© 2011 Pearson Education, Inc.
Figure 40.19
Torpor and Energy Conservation
• Torpor is a physiological state in which activity is
low and metabolism decreases
• Save energy while avoiding difficult and
dangerous conditions
• Hibernation: torpor during winter cold and food
scarcity
• Estivation: summer torpor, survive long periods
of high temperatures and scarce water
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