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

Being Alive Look at problems in many ways Ex/ disease Look at DNA Cell Structure Influence of Diet Basic Organization: Cell Tissue Organ Organ System Organism Biotic- Living Abiotic- Non-living Dead- Once Alive

How do we tell?

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 have a metabolism 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!

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

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