Bio Notes – Characteristics of Life
Biology: study of Life – all parts of it
Life is old: Earth thought to be about 4.5 billion years old, life is thought to be 3.5 - 4 billion years old
Characteristics of Life (G CHORE)
C = CELLS (all living things have cells)
H = HOMEOSTASIS (all living things keep their internal conditions the same )
A = Living things have ADAPTATIONS(traits) that evolve over time
R = REPRODUCE (all living things reproduce and pass DNA on to offspring )
G = GROW and DEVELOP(all living things grow (get bigger) and develop (change & mature)
E =ENERGY (all living things need to get & use energy)
O =ORGANIZED (all living things have organization atoms up to adult organism)
CELLS
All living things are made of cells
Cells are like separate rooms, each with their own function that is determined by their structure
Basic or fundamental unit, building blocks, of living things
Unicellular organisms – made of 1 cell that does it all! Every function that is needed to stay alive
-organisms are IDENTICAL to parents – cannot evolve since they cannot get new traits
Multicelluar organisms – made of many cells each type with their own special structure and function
-organisms are DIFFERENT from parents- because the parents DNA is combined
Cells have membranes, organelles (little organs) and DNA- the instructions for their structure & function
Morphology: Study of the structure of something (STRUCTURE is related to FUNCTION)
HOMEOSTASIS and Respond to Environment
All living things must be able to RESPOND TO THEIR ENVIRONMENT & MAINTAIN HOMEOSTASIS to
Survive
-body constantly monitors its conditions – if something is off, it has to fix it or you could die- hot = sweat
Homeostasis: the maintaining of stable internal body conditions
(your body uses a feedback system to monitor changes)
Stimulus – anything that causes a change in behavior
Response – reaction to a stimulus
Behavior – A complex set of responses
Body works on a feedback system: Most body systems are negative feedback loops
-negatve feedback: a feedback loop that slows down a process
-positive feedback: a feedback loop that accelerates a process
(has NOTHING to do with “good” or “bad” outcomes)
Positive example: embarrassed = you blush = more embarrassed = more blushing
Snow melts = dark ground exposed = more snow melting = more dark ground showing
Negative example: hot = sweat = you cool down
Cold = shiver = you warm up
ADAPTATIONS
Living things have adaptations- traits- that evolve over THOUSANDS and MILLIONS of years
-adaptations: traits that help organisms survive better in their environment
-natural selection:
-PROCESS by which those organisms that have better traits survive and pass the good
traits on, those with traits that don’t help, die before having offspring
-survival of the fittest
-evolution: THEORY that species change over time – a long time – MILLIONS OF YEARS
-happens because of (or through) natural selection
-evolution is the unifying theme of biology – because it indicates all living things are related
-phylogeny – study of the how things have changed or evolved over the history of the earth
-ecology: study of the relationship between organisms and their environment
-biotic factors: term for anything that is alive (it is an organism)
-abiotic factors: term for anything that is not alive, and never was
By studying ecology- we realize everything is INTERDEPENDENT- and one thing relies on an other- one part
gets messed up it messes up other things
Basic part of the environment is the organism
Organism: 1 living thing
Population: a group of all the SAME ORGANISMS
Community: A group of all the organisms
Ecosystem: All the organisms, and all the other non-living parts of the environment
Biosphere: The whole world – it is ALL the ecosystems
REPRODUCTION
All living things can reproduce ( unless it’s due to disease or injury) either sexually or asexually
DNA is passed on to offspring
DNA
- deoxyribonucleic acid
-instructions for everything about you – EVERY CELL HAS THE SAME DNA- ALL INSTRUCTIONS
-genes: short sections of DNA with instructions for a trait (characteristic)
-not all genes are ACTIVE all the time; they have to get TURNED ON or “ACTIVATED”
NOT essential for individual, it IS for the species
2 types –
Sexual and asexual reproduction
Sexual: involves 2 organisms male and female – egg and sperm join
-gamete: sex cells – egg or sperm
-zygote: fertilized egg ( the egg and sperm have joined)
GROW and DEVELOP
All living things grow (by 2 methods)
1. Cell Enlargement -cell grows in size ( they get bigger)
2. Cell Division - cell grows in number (more cells form)
-(non-living things grow by getting more stuff they are made of – icicles, snowballs, etc.)
Development – Process by which a zygote becomes a mature individual by lots of cells growing and
multiplying.
-occurs through repeated cell divisions & cell differentiation
-cell differentiation: Process by which cells start out the same but as they mature they become
different and get their own special function
ENERGY
All living things are autotrophs or heterotrophs
Autotroph – organisms that use light or chemicals to make their own food (also called producers)
-examples: plants, some bacteria
Heterotroph – organisms that must get their food energy by eating other (different) organisms
We have to eat!!!
4 things organisms use food energy for:
1. GROWTH
2. MAINTENANCE of body
3. REPRODUCTION
4. METABOLISM
Metabolism :the sum of all the chemical processes that occur in an organism
2 parts of metabolism:
Catabolism- breaking down substance to produce energy
Anabolism- using energy to put substances together (builds it up)
ORGANIZATION
All organisms are organized at the molecular & cellular level
(electrons, neutrons, protons)  elements  molecules  compounds  cells  tissues  organs –->
organ systems  organisms ( population communityecosystem  biosphere)
Cells and groups of cells are organized by their FUNCTION
Cell – basic unit of living things
2 types:
Prokaryotic: LACK a nucleus & organelles with membranes (BACTERIA)
Eukaryotic: HAVE a nucleus & organelles with a membrane (ALL LIVING THINGS BUT BACTERIA)
Tissue – Group of cells w/ a similar function
Histology: study of tissue
4 main types of tissue:
Connective: tissue that has a variety of functions that include support and protection and connection
Connective tissue is the most abundant and widely distributed in the body
Examples: Loose connective tissue, fat, dense fibrous tissue, cartilage, bone, blood, and lymph
Epithelial: covers the body surface and forms the lining for most internal cavities – can be thin and flat or
cuboidal or elongated
Major functions: protection, secretion, absorption and filtration
The skin is made of epithelial tissue that protects the body from dust, dirt and harmful microbes
Muscular: Tissue that has the ability to contract (shorten)
3 Types:
Skeletal: Voluntary (you control it) – attaches to bones to move them
Smooth: Involuntary (you can’t control it) – found in organs and vessels
Cardiac: Involuntary (you can’t control it) – only found in the heart
Nervous: Long string like tissues they function for message transfer = they receive incoming info from
external stimuli and then conduct impulses to respond
Organ – Group of tissues w/ a similar function
-brain, lungs, heart, pancreas, spleen, stomach, kidney, liver, gall bladder, small intestine, large
intestine (colon)
Ovaries/testes
Organ System – Group of organs with a similar function
ORGAN SYSTEMS
(IM DR LI SCREEN)
I = Integumentary system – skin, hair, nails, sweat and oil glands
-protects against injury, infection and fluid loss, helps regulate temperature
M = Muscular system – Muscles of the body
Provides structure and support, moves the body, moves substances through the body, produce heat
D = Digestive System – mouth, esophagus, stomach, small and large intestine as well as teeth, salivary
glands, liver and pancreas
-breaks down food so it can be absorbed into the blood
-removes indigestible waste
R = Respiratory System – nasal passages, pharynx, larynx, trachea, bronchi, lungs
- Keeps blood supplied with oxygen while removing CO2
L = Lymphatic System – lymphatic vessels, lymph nodes, spleen, tonsils
-cleans the blood of pathogens
-works with the immune system
I = Immune system – Defends against harmful pathogens (things that cause disease)
S = Skeletal system- Bones, cartilage, tendons, ligaments, joints
-Supports the body, protects the internal organs
-Provides levers for the muscles to work on
C = Circulatory system – Heart, blood vessels & blood
- Heart pumps blood throughout body
- Transports O2, CO2, nutrients, wastes, ions, hormones to and from tissues
R = Reproductive system – male and female sex organs that produce sperm or egg
E = Endocrine System – Glands – pituitary, thyroid, adrenal, pancreas, testes, ovaries
- Regulates many body functions, maintains homeostasis, promotes growth & development,
produces hormones (chemical messengers)
E = Excretory System – kidneys, ureters, bladder, colon
- Kidneys remove nitrogen containing waste such as urea, uric acid & ammonia produced from
breaking down proteins and nucleic acids
- Maintains water, electrolyte and acid-base balance of blood
- Colon removes solid waste
N = Nervous System – Brain, spinal cord, nerves
-Detects changes in the body or environment
-Initiates responses by muscles or glands to these changes
-helps maintain homeostasis