characteristics of life essential questions: what are the major characteristics of life? how do we...
TRANSCRIPT
Characteristics of Life
Essential Questions:What are the major characteristics of life?
How do we determine if something is living or non-living?How can we organize this data to help us in our study of
biology?
Explore: The Biology Song!• Watch the short YouTube video called “The Biology
Song.” (Why is it called the biology song?) • Record any descriptions you see/hear about what
makes something living or a living organism.
• The Biology SongWrite your ideas inThe box on your Notes sheet.
1. Composed of Cells• All living things are composed of one
(unicellular) or more (multicellular) cells.
• This leads to levels of organization in more complex living things…– Cells are organized into tissues.– Tissues are organized into organs.– Organs are organized into organ systems.– Organ systems comprise an Organism!
• Organism – Displays all characteristics of life and considered by biologists to be alive.
2. Require Energy• Living organisms require energy; in
the most basic form of ATP. – Obtained through the breakdown of
food and nutrients. (Heterotrophs)– Obtained through inorganic sources
(Photosynthesis, Chemosynthesis)– Obtained through “stealing” ATP from
other organisms. (Microorganisms)• This energy is used to carry out
cell/life functions: metabolism, locomotion, growth/development or cell division, etc.
3. Reproduce• All living things reproduce to carry on their
species.• Some plants and bacteria reproduce
individually via asexual reproduction. – Upon maturity split into two organisms
(budding).– Offspring are genetically identical to parent.
• Some plants and animals reproduce through another member of their species via sexual reproduction.– Upon maturity exchange eggs and sperm
(externally or internally) to create 1 or more offspring.
– Offspring are not genetically identical to parent/s: a unique blend of recombined DNA.
– May or may not have parental care depending on reproductive strategy.
4. Display Heredity• Living organisms inherit
traits from their parent(s) via DNA and/or RNA.
• DNA/RNA are the codes or sequences that get translated into all types of proteins.
• These are found in the nucleus of eukaryotic organisms.
5. Respond to Stimuli• living things respond to changes in light,
heat, sound, and chemical and mechanical contact.
• To detect stimuli, many organisms have means for receiving information, such as skin, eyes, ears, and taste buds (the sensory organs)
• Once a stimulus has been received by the organism, that triggers a response. – Lower organisms (lacking complex sensory
organs) undergo types of taxis.• Phototaxis, Hydrotaxis, Chemotaxis, Geotaxis,
Thigmotaxis, Magnetotaxis, etc.– Higher organisms (with complex sensory
organs) undergo behaviors often using chemical messengers (called hormones.)• Conditioning, Imprinting, Insight learning, etc.
6. Adapt to their Environment• Organisms and Species adapt to
their environment in order to survive.
• Adaptation occurs to best suit the habitat, and may or may not be reversible. – Add fat/fur in the wintertime.– Changing coat colors to elude
predators.– Learned behaviors to avoid harm.
7. Maintain Homeostasis• All organisms maintain a stable internal balance, also known as homeostasis.• This ensures that body systems work at their best levels.
– Temperature, pH, Water/Osmotic Pressure, Salt balance• This is accomplished by various types of feedback loops.
– Positive Feedback loop: accelerates or enhances the output created by a stimulus that has already been activated.• Blood clotting, Oxytocin release during birth
– Negative Feedback loop: reducing the output or activity of any organ or system back to its normal range of functioning• Shivering/Sweating, Blood Pressure
8. Evolve (over time)• All organisms as a population (not
individually) evolve to the changing environment over time.
• Occurs via changes in DNA sequences (mutations) that code for proteins (known as traits)– Those with beneficial mutations will
survive and reproduce in the changing environment and pass them on to future offspring.
– Those without beneficial mutations will not survive and not reproduce in the changing environment.
Example: Antibiotic resistant bacteria!
Reflect: The Biology Song!
• Re-watch the short YouTube video called “The Biology Song.”
• Did you hear anything different this time?
• Why is it called the Biology song?
• The Biology Song
What am I? Living or Non-Living?
• In the following slides, you will see a picture of an object. – Observe the object. (Quantitative and Qualitative) – Feel free to ask questions about the object.
• Identify the aspect of living things it represents. – (Remember, it must meet all criteria to be considered
a living organism!)
• Determine if it is Living or Non-Living!…We’ll start of easy…
What am I?
What am I?
What am I?
What am I?
What am I?
What am I?
Your Turn! Mind Mapping• To conclude today,
you will create a bubble map on the back of your notes.
• Flip over and look at the diagram. Describe the 8 major characteristics of life.