Five Quick Questions:1) What is Homeostasis?2) What two stages does Homeostatic
mechanisms consist of?3) What is the role of the negative
Feedback System?4) Outline the stages of the Negative
Feedback System5) What is a positive Feedback System?
Answers1) Homeostasis is the maintenance of a
constant internal environment2) Detection of changes by receptor and
Counteraction of changes by effector3) The responsive reaction to reduce and
counteract stimulus4) Input Receptor Control Centre Effector
Response (Output)5) A positive feedback system is where the
response to a stimulus is to amplify the change instead of reducing it
Maintaining A Balance – Response to Temperature
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)
Ectotherms and EndothermsEctotherm: Endotherm:
-Same body temperature as ambient temperature
-Limited ability to maintain temperature
-Use behavioral adaptations to maintain temperature
-’Cold-Blooded’
E.g. plants, reptiles, amphibians
-Have physiological structures that maintain body in narrow range irrespective of the ambient temperature
-Use heat produced in metabolism
-’Warm-Blooded’-E.g. mammals, birds
What am
I and how do I
maintain body Tem
perature?
LizardCheetah
If we were to graph the Body temperature of these two animals in an ambient temperature how do you think it would look?
Responses to Temperature Change
Physiological Adaptation:
- Helps regulate function within an organism
- Involves biochemical reactions within cells and tissues
- E.g. Rates of metabolism
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
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
Adaptations for Temperature Control in Australian endotherms: The Red Kangaroo
Physiological Structural BehaviouralCold Conditions (Winter Months)Warm Conditions (Summer Months)
Activity:What adaptations does the Australian Red Kangaroo have to control body temperature?
Have a go at filling in the table
Adaptations for Temperature Control in the Red Kangaroo
Physiological Structural BehaviouralCold Conditions (Winter Months)
Increased metabolic rate to create more heat within the body
- Fur Basking in the sun
Warm Conditions (Summer Months)
Decrease in metabolic rate
-Exposed areas of skin to increase evaporative cooling-Shunting blood from tail to the exposed area of the skin on the forelegs to increase heat loss
-Nocturnal-Licking forelegs to increase evaporation from the skin-Sitting in the shade-Panting to release heat
Adaptations for Temperature Control in Australian ectotherms: The Diamond Python
Physiological Structural BehaviouralCold Conditions (Winter Months)Warm Conditions (Summer Months)
Activity:What adaptations does the Australian Diamond Python have to control body temperature?
Have a go at filling in the table
Adaptations for temperature control in Australian ectotherms: The Diamond Python
Physiological Structural BehaviouralCold Conditions (Winter Months)
- Lies on eggs and shivers to increase the temperature of incubation
- Dark in colour to absorb heat and therefore can tolerate colder temperatures than other snakes
- Basks in the sun to raise body temperature- Hibernation- Migration to warmer areas.
Warm Conditions (Summer Months)
- Is nocturnal, hunting at night to escape the heat during the day.
Plant Responses to Temperature Change
Are plants endothermic or endothermic?
Plant Adaptations to Control TemperatureLeaf 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
Plant Adaptations to Control TemperatureDie 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 – Banksia ericifolia
Vernalisation: Must be exposed to cold conditions to reproduce E.g. plants that live in alpine conditions
ActivityAim: To describe adaptations and responses in
two Australian animals (One endotherm and one ectotherm) and two Australian plants that assist in temperature regulation
Method:1) Choose two Australian animals and two
Australian plants2) Collect information from several sources about
adaptations that these organisms have that assist them in temperature control
3) Enter the information into a table
Adaptations and Responses that Assist in Temperature Regulation - Table
Organism Habitat
Optimum Temperature Range
BehaviouralAdaptation
Physiological Adaptation
Structural Adaptation
Animal 1Animal 2Plant 1Plant 2
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