Adaptations for survival 1 EL: To see what we already know about adaptations and begin learning about different types of adaptations
Activity • Complete first column of the “Adaptations Biq Questions” worksheet • Put any other questions you have about adaptations at the end • Hand in when you are done (don’t keep it!!!) – you’ll get it back at the end to see how much you have learnt!
What is survival? Organisms that are considered “successful” at surviving in their environment: • Survive to reproductive age • Reproduce and have enough young to ensure survival of the next generation
Adaptations • An adaptation is a feature that seems to equip an organisms for survival in a particular habitat. • Adaptations can be structural, behavioural or physiological.
Structural Adaptations • Features of the shape and structure of the organism that help it to survive in it’s environment • Think of one example in an animal and one example in a plant and write it down in your table.
Behavioural Adaptations • Behaviours undertaken by an organism that help it to survive in it’s environment • Think of one example in an animal and one example in a plant and write it down in your table
Physiological Adaptations • Features of the organisms internal physiology (e.g. body temperature, water balance, heart rate, blood pressure ect) that help it to survive in it’s environment • Think of one example in an animal and one example in a plant and write it down in your table
activity/homework • Page 291, qu 19, 22 • Page 292, Biochallenge qu 5 • Page 295 qu 11 • Animal adaptations worksheet (to be handed in next lesson)
Reflection • From completing the big questions, how would you rate your pre-existing knowledge of adaptations from 1 (terrible) to 10 (very good)?
Adaptations for Survival 2: Physiological EL: To begin learning about physiological adaptations, focusing on homeostasis
Homeostasis • Organisms cannot survive unless they are able to control the internal environment of their body, despite continual changes in their surroundings. • Homeostasis = The maintenance of a constant internal environment despite changes in the external environment.
What needs to be kept within narrow limits? M.I.T.G.O.W.B + pH + wastes • Metabolites (eg blood glucose concentration) • Ions (eg salts) • Temperature • Gases (eg CO2 and O2) • Osmolarity (ie water balance) • Wastes (e.g. urea) • Blood Pressure • pH
Stimulus-response model Receptor Stimulus Transmission - nerves Control centre Transmission – nerves or hormones Response Effector
Stimulus-response model exampleNegative Feedback Transmission - nerves Negative feedback – response counteracts the stimulus Transmission - nerves
Reflection and Homework • What have you learnt about homeostasis? • Homework: Quick check qu: 1-4 pg 301
Adaptations for Survival 3: Physiological EL: To demonstrate our understanding of homeostasis and to learn about the involvement of the nervous and endocrine systems
Activity • People here last week: • Individually or in groups of up to 4 people, use the stimulus-response model to explain homeostasis. You can do this by either: • Performing a role play • Writing and performing a song or rap • Creating and performing an interpretive dance • Creating a poster and presenting it to the class You have 10 mins to prepare and then have to present it.
The nervous system • This communication system controls and coordinates functions throughout the body and responds to internal and external stimuli. • Maintains homeostasis by detecting change and coordinating the action of effector organs • Responsible for unidirectional, fast communication by electrical impulses
Cerebrum brain Cerebellum Medulla Oblongata Spinal Cord The Central Nervous System (CNS) • Consists of the brain and spinal cord
The peripheral nervous system (PNS) • Nerves extending out to the rest of the body from the CNS • Includes all sensory neurons, motor neurons, and sense organs
Nerve cells: Neurons • The basic functional unit of the nervous system. • Send impulses to and from the CNS and PNS and the effectors (muscles/glands)
Types of Neurons • Affector/sensory neuron: • Receive incoming stimuli from the environment to CNS • located near receptor organs (skin, eyes, ears). • Connecting neuron/ • interneuron: • Relay messages between other neurons such as sensory and motor neurons. • Usually found in brain and spinal cord. • Effector/motor neuron: • Carry impulses from CNS to effectors to initiate a response • located near effector (muscles and glands)
Fun Fact: Where can the largest cells in the world be found? The giraffe’s sensory and motor neurons! Some must bring impulses from the bottom of their legs to their spinal cord several meters away!!
Types of receptors Mechanoreceptorsrespond to mechanicalenergy (e.g. ear drum) Thermoreceptorsrespond to heat or cold (e.g. nerve endings in skin) Electromagneticreceptorsrespond to electromagnetic energy (e.g. ampullae of Lorenzini in sharks) Photoreceptorsrespond to visible light and UV radiation (e.g. eyes). Chemoreceptors respond to chemical stimuli (e.g. olfactory)
Video • http://www.youtube.com/watch?v=xRkPNwqm0mM • http://www.youtube.com/watch?v=i-NgGKSNiNw
Activities • Complete Quick check qu 5&6 pg 308 • Complete Chapter Review Question 3 on page 237
Endocrine System • Uses chemical signals for cell to cell communication • Coordinates the function of cells • Response to an endocrine signal occurs within minutes to hours
Endocrine System Endocrine glands Release hormones into the bloodstream. Hormones Chemicals released in one part of the body that travel through the bloodstream and affect the activities of cells inother parts. body.
Controlling Glucose levels • Your cells need an exact level of glucose in the blood. • Excess glucose gets turned into glycogen in the liver • This is regulated by two hormones produces by the pancreas: insulin and glucagon
Glycogen If there is too much glucose in the blood, insulin converts some of it to glycogen Insulin Glucose in the blood
Glycogen If there is not enough glucose in the blood, glucagon converts some glycogen into glucose. Glucagon Glucose in the blood
Activity • Complete quick check qu 7 pg 308 • Complete “Nerves and Senses” Worksheet
Reflection and homework • How did the group activity help you to understand homeostasis better? • What did you learn about the nervous system today? Homework: Complete any unfinished questions
Adaptations for Survival 4: Physiological EL: To learn how animals and plants regulate temperature
Detecting temperature change • Most organisms have an optimal internal and/or external temperature range • E.g. Humans: internal temp approx 37oC • E.g. coral: external temp approx 26oC • Why? Optimal temperature for enzymes and other internal processes. Above or below can lead to lower functioning and possibly even death.
Detecting temperature change: Humans • External temp change detected by receptors in skin – one type for detecting cooling, another for heating • Internal temp receptors found deep within body – mostly within brain, near spinal cord, around large veins and in digestive system • Affector (sensory neurons) relay the information to the hypothalamus – the temp control centre of the body
Maintaining core temperature • Interaction of nervous and endocrine systems • Maintenance requires heat gain balancing heat loss – done in a number of ways
Losing heat • Heat can be lost through radiation , conduction, convection and evaporation