Life in the earth system Unit1: Intro to biology

Big questions How are the Earth Systems organized? How do the systems interact to maintain organization? How do we classify something as biotic or abiotic? (living or non-living)

Studying Science Scientific Method- PHEOC Problem, Hypothesis, Experiment, Observation, Conclusion A scientific theory is NOT a wild guess. It must be consistent with known experimental results and it must have predictive power. As new knowledge is gained, theories are refined to better explain the data. A law is a mathematical relationship that is consistently found to be true. Can YOU think of an example of a theory and a law in science?

Studying science Hypothesis- Proposed scientific explanation (answer) for the problem the scientist is attempting to figure out. Independent Variable- The factor that is changed by the scientists in order to prove -or- disprove the hypothesis. CHANGE ONE AT A TIME Dependent Variable- The factor that is measured or observed as the independent variable is changed. Control- A factor kept the same in order to pinpoint where and why the change is taking place.

Studying science Qualitative Data- Observations in words. Description Quantitative Data- Numbers used to make data tables or comparisons

Let’s do some science! Capsule Lab

Title Dependent Variable Units and Scale Independent Variable

How do we tell if something is alive?

Rule #1: Living things are made of cells Cells are the units of structure in living organisms Also units of function in living organisms Cell = smallest unit capable of all life functions

Rule #2: Living things reproduce They can make more of themselves Two kinds of “Getting’ Jiggy With It” sexual reproduction = two cells from different parents unite -ex. Your mommy and daddy (ewww!), dogs, cats, worms, asexual reproduction = new organism has a single parent -ex. Some plants, bacteria, starfish (!!!)

Rule #3: Living things are based on genetic code Have DNA Can pass on traits

Rule #4: Living things grow and develop Even single celled organisms grow into mature cells Organism= what scientists call living things

Rule #5: Living things obtain and use energy Metabolism = combination of chemical reactions through which an organism builds up / breaks down materials as it carries out its life processes Energy is used to perform chemical reactions Materials (nutrients) are the raw materials for building biological structures

Rule #6: Living things respond to their environment Stimuli = A physical or chemical change in the environment that leads to a response Respond = to act or do something in reaction to something else Can be INTERNAL STIMULUS or EXTERNAL STIMULUS Thirst, pain, hunger, cold, hot………

Rule #7: Living things maintain homeostasis Homeostasis= maintaining stable internal conditions Homeo = similar/alike Stasis = state of no change

Rule #8: Living things, as a group, change over time Great diversity of life on Earth Adapt to the environment (changing environment) Adaptations can be structural, physiological, behavioral Populations show variations in their genetic code Evolution = ability of group of organisms to change over time

Let’s Focus on Homeostasis LAB TIME!

How did Mick Fanning’s body coordinate and interact to return to homeostasis after this shark attack? Why is it important to keep our body within certain ranges?

Click to play video or find on CNN at http://www. cnn

Instructions 1) In the three drawings below, draw what is happening in Mick’s body before, during, and after the shark attack. 2) In the boxes, draw and label the body, the parts of the body, and how they interact with each other and the environment. 3) After drawing your models, use the lines to write an explanation about what is happening at each point in time. 4) For each picture, be sure to include the ideas from the “Gotta Have Checklist”

Describe how the body maintains normal homeostasis. Gotta Have Checklist Show all the interactions the body has with itself and its environment. Identify the movement of materials within the body. Use arrows to show relationships. Describe how the body maintains normal homeostasis.

Life in the earth system System- set of interacting components that work together Inputs and outputs- outputs (what we see/ feel) are generated when inputs (message to brain and hormones) are analyzed in some way Feedback- information from one step of a cycle that acts to change a behavior of a previous step Feedback Loop- feedback output that in turn becomes an input

Feedback Mechanisms Big Idea #2: Biological systems use energy to grow, reproduce, and maintain dynamic homeostasis.

Essential Knowledge 2C1: Organisms use feedback mechanisms to maintain their internal environments and respond to external environmental changes

Dynamic Homeostasis Living things maintain stable internal conditions Examples in humans: Temperature pH Solute concentrations (Ca, Fe, Salt, Glucose etc.) Heart rate/blood pressure/Breathing rates Oxygen/CO2 concentrations

Feedback Mechanisms Responses to environment to maintain homeostasis

Negative Feedback Returns a changing condition back to its target set point. Ex: Return body to normal conditions

Negative Feedback– Hot!! Beckham sweats b/c he is hot (literally)  Sweat evaporates, removing heat  Becks cools down!

Negative Feedback – COLD!! Cold means Becks is losing heat  shivers/ shakes to generate heat  His body goes through cellular respiration to convert sugar/fat (like he has any)  heat  blood is diverted from skin  Stops losing heat!

BODY EXAMPLE: GLUCOSE High blood sugar levels long term cause cell/organ damage Low blood sugar leads to fatigue, impaired functioning, fainting, brain damage, etc.

Pancreatic Regulation Insulin Glucagon Hormone that causes cells to take in glucose Lowers blood glucose levels Triggered by high blood glucose levels Hormone that raises blood sugar levels (breaks down glycogen into glucose) Triggered by low blood sugar

Body Example: Water When you have too much water  pee it out (ANF) When you need to save water, anti‐diuretic hormone (ADH) is released – Concentrates urine, decreases sweating, inhibits water loss, increases water absorption

Positive Feedback Response to the stimulus is amplified i.e. you eat an appetizer, that makes you more hungry so you eat more food

Contractions start  More contractions leads to more release of oxytocin  Leads to more contractions (frequent and stronger) PUSH! Ex: Birth

Recap on homeostasis

Negative Feedback Loop Imbalance message received and inputs signal opposite to output. Ex/ I am hot (output) therefore I will sweat (input) Thermoregulation (if body temperature changes, mechanisms are induced to restore normal levels) Blood sugar regulation (insulin lowers blood glucose when levels are high ; glucagon raises blood glucose when levels are low)

Positive Feedback Loop Reinforcing mechanism that adjusts output in the same direction as the input Very rare Examples of processes that utilize positive feedback loops include: Childbirth – stretching of uterine walls cause contractions that further stretch the walls (this continues until birthing occurs) Lactation – the child feeding stimulates milk production which causes further feeding (continues until baby stops feeding) Blood clotting – platelets release clotting factors which cause more platelets to aggregate at the site of injury