1. Organisms Communicate
Timing & Communication

2. Review: Cells Communicate
Cells detect chemistry/environmental conditions
Signal Transduction Pathway

3. Review: Cells Communicate
Cells within organ systems communicate
Immune System: Contact (helper T)
Nervous System: Short Distance (synapse)
Endocrine System: Long Distance (hormones)

4. Organisms Communicate
Communication needs timing and coordination
Bacteria
Fungi
Plants
Animals

5. Maintaining Homeostasis
Feedback Loops
Maintaining Homeostasis

6. As we move through this unit….
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

7. Alteration of feedback mechanism
Leads to harmful effects on individual
Ex: diabetes

8. Physiological Events
Organisms respond to changes in their environment through behavioral and physiological mechanisms

9. Bacteria Examples
Using energy to respond to the environment to maintain homeostasis

10. Chemotaxis Directed movement in response to stimulus
toward attractant: food
away deterent: poison
Structure: flagellum

11. Quorum Sensing Bacteria expel proteins in normal lifecycle
Populations increase other functions begin

12. Endospores
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

13. Fungi Examples
Using energy to respond to the environment to maintain homeostasis

14. Fruiting Body
Occur as a result of internal and external signals that synchronize with environmental cycles and cues
Ex: development in response to nutritional depletion

15. Plant Examples
Using energy to respond to the environment to maintain homeostasis

16. Phototropism Growth in response to light Mechanism: auxin hormone
(positive) toward light shoots
(negative) roots down
Mechanism: auxin hormone

17. Photoperiodism Response to timing of light Mechanism: phytochrome
Determine time of day/season
Mechanism: phytochrome

18. Ripening of Fruit
Positive feedback mechanism
Mechanism: Ethylene

19. Plasmodesmata
Plants pass materials between cells

20. Defensive mechanisms Physical defense: Chemical defense:
Thorns, trichomes
Chemical defense:
Glycosides
Symbiotic defense:
Recruitment of animals

21. Pollination
Flower development

22. Water availability
C4 plants

23. Animal Examples
Using energy to respond to the environment to maintain homeostasis

24. Behaviors
Response of a muscle or gland under control of the nervous system in response to a stimulus
Innate vs. Learned

25. Orientated Movement Kinesis Random movement in response to stimulus
Ex: Paramecium slow down and turn more often in the presence of bacteria (food)

26. Orientated Movement Taxis Direct movement toward/away from stimulus
Ex: American Cockroach hides from light

27. Migration Regular long distance change in location
Mechanism (in birds)
Magnetite in brain to visualize magnetic field

28. Hibernation
Lowering of metabolism to survive seasons

29. Communication
Honeybees perform the waggle dance to communicate the location of food sources

30. Communication
Pheromones
Ex: alarm or reproductive

31. Courtship

32. Cooperation
Pack behavior in animals

33. Habituation
A loss of responsiveness to stimuli that convey little or no new information
Ex: prairie dog alarm call in human presence

34. Associative Learning
Ability to associate one environmental feature with another
Ex: Mouse associates color/taste

35. Imprinting
The process of recognizing and following the first moving object encountered during a “sensitive period” of life (learned/innate)

36. Imprinting
Scientists often wear costumes to prevent human imprinting with endangered species

37. Cognition & Problem Solving
The process of knowing by awareness, reasoning, recollection & judgment.
Ex: primates learn how to use tools