Download Timing and control

 Use free energy to maintain homeostasis in response
to environmental conditions
 In order to survive, organisms need:
Timing and Coordination
 Diversity of life on Earth
 6 kingdoms
 Organisms detect environment conditions
 Organisms communicate
 Endocrine, Immune, Nervous System
 Animal behaviors
Maintaining homeostasis
 Negative feedback:
returning the changing
condition back to its
target set point
 Ex: temperature
regulation in animals
 Ex: plant responses to
water limitations
 Positive feedback:
amplification of a
response by moving away
from its set point.
 Ex:ripening of fruit
 Ex: labor in childbirth
 Leads to harmful effects on individual
 Ex: diabetes
Respond to a changing environment by using energy to
maintain homeostasis
 Organisms respond to changes in their environment
through behavioral and physiological mechanisms
 Excretory system in flatworms earthworms and
vertebrates
 Osmoregulation in bacteria fish and protists
 Osmoregulation in aquatic and terrestrial plants
 Thermoregulation in aquatic and terrestrial animals
Using energy to respond to the environment to maintain
homeostasis
 Directed movement in response to stimulus
 toward attractant: food
 away deterent: poison
 Structure: flagellum
 Bacteria expel proteins in normal lifecycle
 Populations increase other functions begin
 When environment lacks specific nutrients, bacterial
cell develops protective cell
 Genome is copied
 Water is removed
 Metabolism stops
 Original cell lysis
 Endospore endures
 Dormant for centuries
Using energy to respond to the environment to maintain
homeostasis
 Occur as a result of internal and external signals that
synchronize with environmental cycles and cues
 Ex: fruiting body development in response to nutritional
depletion
Using energy to respond to the environment to maintain
homeostasis
 Growth in response to light
 (positive) toward light shoots
 (negative) roots down
 Mechanism: auxin hormone
 Response to timing of light
 Determine time of day/season
 Mechanism: phytochrome
 Positive feedback mechanism
 Mechanism: Ethylene
 Plants pass materials between cells
 Physical defense:
 Thorns, trichomes
 Chemical defense:
 Glycosides
 Symbiotic defense:
 Recruitment of animals
 Flower development
 https://vimeo.com/75555419
 C4 plants
Using energy to respond to the environment to maintain
homeostasis
Contact Plant Cells
Short Distance
Contact Animal Cells
Long Distance
 Hormones (Endocrine System)
 Antigens (Immune System)
 Neurotransmitters (Nervous System)
 http://www.dnatube.com/video/1113/The-Endocrine-
System-How-it-Functions
 Molecules produced by endocrine cells
 Typically travel through circulatory system
 Medicine:
 Birth control
 Depression
 Blood pressure
 Metabolism
 https://www.youtube.com/watch?v=zQGOcOUBi6s
 Defenses that activate immediately upon infection
 Organism Barrier: Chitinous exoskeleton
 Cellular: Hemocytes ingest bacteria
 Molecular: Lysozyme enzymes break cell walls
 Organism Barrier: Skin
 Cellular: Neutrophils and macrophages
 Molecular: Interferon & 30 protein complement
system
 Histamine and citokine signals trigger capillaries to
dilate
 Vertebrate defenses remembered after initial
exposures
 https://www.youtube.com/watch?v=z3M0vU3Dv8E
 https://www.youtube.com/watch?v=x4PPZCLnVkA
 http://highered.mheducation.com/sites/0072495855/s
tudent_view0/chapter14/animation__the_nerve_impu
lse.html
 Response of a muscle or gland under control of the
nervous system in response to a stimulus
 Innate vs. Learned
 Kinesis
 Random movement in response to stimulus
 Ex: Paramecium slow down and turn more often in the
presence of bacteria (food)
 Taxis
 Direct movement toward/away from stimulus
 Ex: American Cockroach hides from light
 Detection of light to set internal clock
 Mechanism: pineal gland detecting sunlight
 Regular long distance change in location
 Mechanism (in birds)
 Magnetite in brain to visualize magnetic field
 Lowering of metabolism to survive seasons
 Honeybees perform the waggle dance to communicate
the location of food sources
 Pheromones
 Ex: alarm or reproductive
 Pack behavior in animals
 A loss of responsiveness to stimuli that convey little or
no new information
 Ex: prairie dog alarm call in human presence
 Ability to associate one environmental feature with
another
 Ex: Mouse associates color/taste
 The process of recognizing and following the first
moving object encountered during a “sensitive period”
of life (learned/innate)
 Scientists often wear costumes to prevent human
imprinting with endangered species
 The process of knowing by awareness, reasoning,
recollection & judgment.
 Ex: primates learn how to use tools