Five Quick Questions:

1. Five Quick Questions: • What is Homeostasis? • What two stages does Homeostatic mechanisms consist of? • What is the role of the negative Feedback System? • Outline the stages of the Negative Feedback System • What is a positive Feedback System?

2. Answers Homeostasis is the maintenance of a constant internal environment Detection of changes by receptor and Counteraction of changes by effector The responsive reaction to reduce and counteract stimulus Input  Receptor  Control Centre  Effector  Response (Output) A positive feedback system is where the response to a stimulus is to amplify the change instead of reducing it

3. Maintaining A Balance – Response to Temperature

4. Temperatures Across The Globe • Many climate zones (Tropical-Deserts) • Earth temperatures vary from -75 – 50 degrees • Most animals and plants cannot tolerate extreme temperatures • Behavioral structural and physiological adaptations allow them to maintain temperature within narrow range • E.g. Mammals (0-45 degrees) • E.g. Iguana (24-31 degrees)

5. Ectotherms and Endotherms

6. What am I and how do I maintain body Temperature? Lizard Cheetah If we were to graph the Body temperature of these two animals in an ambient temperature how do you think it would look?

7. Responses to Temperature Change Physiological Adaptation: • Helps regulate function within an organism • Involves biochemical reactions within cells and tissues • E.g. Rates of metabolism

8. Responses to Temperature Change Structural Adaptation: -Organisms that have physical features which make them better suited to their environment -Can be both physiological and structural E.g. Length of Kidney Tubule, helps decrease water loss and Big ears for cooling

9. Responses to Temperature Change Behavioural Adaptation: -Ways in which animals behave that help it survive in its natural environment E.g. Basking in the Sun, Migration, Nocturnal Activity -Mostly used by ectotherms

11. Adaptations for Temperature Control in Australian endotherms: The Red Kangaroo Activity: What adaptations does the Australian Red Kangaroo have to control body temperature? Have a go at filling in the table

12. Adaptations for Temperature Control in the Red Kangaroo

13. Adaptations for Temperature Control in Australian ectotherms: The Diamond Python Activity: What adaptations does the Australian Diamond Python have to control body temperature? Have a go at filling in the table

14. Adaptations for temperature control in Australian ectotherms: The Diamond Python

15. Plant Responses to Temperature Change Are plants endothermic or endothermic?

16. Plant Adaptations to Control Temperature Leaf Fall: In hot conditions plants will reduce surface area by dropping leaves also reducing transpiration Shiny leaves:Shiny leaves that reflect solar radiation e.g. sand dunes Heat-Shock Proteins: Produced under stress in high temperatures – These molecules are thought to stop enzyme denaturing so normal cell reactions can occur Transpiration: Movement of water from roots to leaves cools plant

17. Plant Adaptations to Control Temperature Die Back: Shoots and leaves die, but left in soil are bulbs, roots or rhizoids that grow again in favorable conditions Orientation of Leaves: Drooping of leaves towards ground, reduces surface area and directs water to roots E.g. Eucalyptus Seed Dispersal: Germinate by fire E.g. Australian Native plants – Banksiaericifolia Vernalisation: Must be exposed to cold conditions to reproduce E.g. plants that live in alpine conditions

18. Activity Aim: To describe adaptations and responses in two Australian animals (One endotherm and one ectotherm) and two Australian plants that assist in temperature regulation Method: • Choose two Australian animals and two Australian plants • Collect information from several sources about adaptations that these organisms have that assist them in temperature control • Enter the information into a table

19. Adaptations and Responses that Assist in Temperature Regulation - Table