All living things share certain characteristics:
1) They are made of cells, metabolize energy, respond to stimuli, reproduce, evolve over generations, and maintain homeostasis.
2) They are organized into hierarchical levels from cells to organisms and ecosystems.
3) They grow and develop throughout their lifecycles according to their unique processes of asexual or sexual reproduction.
2. However…….
What is life?
How do we know what is alive/not alive?
What makes things living?
How do I
know if I’m
really
alive??
3. WHOOO’s
Mrs. O. Cheg?
Mrs. O. Cheg is how you can
remember the characteristics that
all living things share!
M: Metabolism (Energy)
R: Reproduction
S: Stimuli
O: Organization
C: Cells
H: Homeostasis
E: Evolve Over Generations
G: Grow & Develop
4. Living things obtain and use energy.
All organisms need to process materials to gain the energy
needed to carry out life processes.
The sum of all the chemical reactions that an organisms uses to
build up or break down materials is called metabolism.
Examples of Metabolic Processes are:
Photosynthesis
Cellular Respiration
Digestion
Excretion Mitochondrion = Powerhouse of Cell
Chloroplast = Sunlight Converter
5. Living Things Reproduce
All organisms produce new similar organisms through the
process of reproduction.
Sexual Reproduction:
Sex Cells (sperm and egg) from two individual parents
unite to create a new organism.
Most plants and animals reproduce sexually.
Asexual Reproduction:
One single organism produces genetically identical offspring.
Bacteria, some worms, hydra, and some plants reproduce
6. Living Things Respond to Stimuli
All living things must be able to detect and respond to a changing
environment.
Stimulus (Stimuli): a signal that an organism can respond to.
Response: a reaction, or change in action, that is brought
on by a stimulus.
Examples:
You touch a hot pan (stimulus) and you pull your hand away (response).
Pupils constrict (response) when light becomes brighter (stimulus).
A plant releases unsavory chemicals to ward off insects and caterpillars that
feed on their leaves.
7. All Living Things Are Organized
Biosphere—Earth
Ecosystem – All biotic and abiotic factors in an area
Community – All living organisms in an area
Population – one type of species living in an area
Organism – any living thing
Organ System – group of organs working together
Organ – group of different tissues working together
Tissue – group of cells (same type) working
together
cell – basic unit of life
organelle – tiny working parts of a cell
molecule – groups of atoms bonded
together
8. All living things are made of one or more cells.
Cells are the smallest units considered to be fully alive.
Some organisms are multicellular (humans have trillions of cells)
and some have one cell and are called unicellular (bacteria).
Some organisms have prokaryotic cells (do not have a nucleus)
while others have eukaryotic cells (contain a nucleus).
Cells:
All organisms begin their lives as a single cell.
All cells contain a universal genetic material called DNA.
All cells exhibit the characteristics of living organisms (respond to stimuli, reproduces,
require energy, evolve, maintain homeostasis, grow and develop)
9. Most reptiles, invertebrates,
fishes, and amphibians are
ectoderms. (However, many do
not wear clothes as pictured.)
All Living maintain a stable internal
environment.
All organisms maintain homeostasis when they keep their
internal environmental stable, even when external conditions
drastically change and become unfavorable.
All body systems work together to maintain homeostasis.
Helps to prevent infections and disease.
Maintains chemical controlling hormones.
Regulates body temperature.
Examples:
Ectotherms are “cold blooded”
Endotherms are “warm blooded”
10. As a group, living things evolve over generations
over time.
To evolve, means to change over long periods of time.
Evolutionary change has linked all forms of life to a common origin over 3.5
billion years ago!
Evidence of Evolutionary Change
Living Organisms
Fossils
Physical Features
Protein Structure
DNA Sequences
11. Living Things Grow and Develop
Every organism has a different way of growing and developing.
Growth is the process of getting bigger (increase in material and structures)
Development is the process of change that occurs in an organism’s life (puberty,
metamorphosis)
In Sexual Reproducing Organisms
A single fertilized egg grows and divides into more cells.
These cells specialize and multiply to make up parts of the body.
In Asexual Reproduction:
An organism buds off, creates runners, or clones itself, making genetically identical
organisms.
These new organisms grow by making new cells and eventually asexually reproducing
Welcome to our Characteristics of Life Mini-Lesson Video
https://www.youtube.com/watch?v=juxLuo-sH6M
Introduction to Characteristics of Life (3:40)
Biology is the study of life. But what does it mean to be living? What characteristics do YOU have that make you a living organism?
Life is so diverse! All living things…no matter how different from each other they may be…from the tallest to the smallest, all living things share a set of common characteristics.
All living things obtain and use energy to grow, develop, reproduce, and repair damage. Many living organisms can convert energy into motion. So…energy is used to carry out everything you do!
Plants obtain this energy from the sun. Animals obtain their energy from food. Some organisms, such as the beagle, are known to take in more energy than is required to sustain them. This excess energy gets stored in the form of fat.
As you’ll learn later in this chapter, energy doesn’t just flow through individual organisms; it also flows through communities of organisms, or ecosystems, and determines how organisms interact with each other and the environment.
In Unit 2 we will discuss in detail the metabolic processes of Photosynthesis and Cellular Respiration. Digestion and Excretion will be discussed in Unit 3.
Reproduction is the production of offspring similar to themselves.
Reproduction is NOT essential to the survival of an individual organism BUT it IS essential for the continuation of the species. What this means is that if an individual female decides that she does not want to have children, this decision will not end her life. But if all females of the species decided they were not having children…the species will eventually die out and no longer exist.
Reproduction can be sexual or asexual. Organisms reproducing sexually do not always have “sex!” In many cases sperm and egg are released into the water where they meet. Most familiar organisms - from maple trees to birds and bees - reproduce sexually.
In asexual reproduction, a single organism can reproduce without the aid of another. Sometimes these organisms can just divide themselves in two!
We will discuss reproduction in further detail in Unit 4.
All living things respond. They have some movement. If something moves, it responds.
Organisms respond to their environment. The term environment refers to an organism's surroundings. Anything in the environment that causes an organism to react is called a stimulus.
Examples of stimuli include:
Light
Temperature
Odor
Sound
Gravity
Heat
Water
Pressure
Responses can be positive or negative. If the organism moves toward the stimulus, such as me moving toward a plate of chocolate chip cookies, we call this a positive response.
What are some other positive responses?
Find food
Find mate
Find water
It is called a negative response when the organism moves away from the stimulus. For example, roots have a negative response to sunlight. They grow away from it. If you touch your hand to a hot pan, you will have a negative response. (If you don't, you should have some serious concerns.)
What are some other negative responses?
Move away from toxins
Escape predators
Complex organization patterns are found in all living things. They arrange themselves on very small levels, grouping like things together. On larger levels, they become visible. This also has to do with differentiation, as the cells are organized in a manner that makes sense for the organism after they change to what they will be in the final organism. You will need to know these levels in order…they will come up again later in this unit and again in Unit 3.
Life is totally cellular! Cells are the basic unit of life. All living organisms are made of one or more cells.
Organisms can be grouped by their number of cells: Unicellular (made of one cell) and multicellular (made of many cells). Cells in multicellular organisms, like ourselves, become differentiated and specialized to perform different jobs for the organism.
Organisms can also be grouped by the type of cells they have. Prokaryotes have cells that lack a nucleus to house the genetic material. Eukaryotes have a nucleus.
All organisms begin life as a single cell. All cells contain DNA and exhibit the 8 characteristics of life this video is about.
Fun Fact: Our genetic code is 50% identical to bananas and 98.8% identical to chimpanzees!
Discovery Video: Cells (3:35)
https://www.youtube.com/watch?v=u54bRpbSOgs
https://www.youtube.com/watch?v=zwibgNGe4aY
What is DNA and How Does It Work? (5:24)
All living organisms maintain homeostasis…a stable internal environment, despite conditions in the external environment.
All organisms have stable internal conditions which must be maintained in order to remain alive. These include temperature, water content, heartbeat, and other such things. In a way, this has to do with energy use because a certain level of energy must be kept within the body at all times. For this, obviously, humans must then ingest food on a regular basis. Not all conditions are for the body to maintain itself, though most are.
Body temperature regulation: too hot – sweat; too cold – shiver
Maintaining blood glucose levels: controlled by two hormones secreted by the pancreas. If they are too high (eating) – insulin released; too low (not eating) – glucagon released.
We will discuss homeostasis and the mechanisms it uses to maintain this balance more in Unit 3.
Evolution is the process by which species change over time. Natural selection is the mechanism for evolution.
Organisms are diverse because they are adapted to different ways of life. An adaptation is an inherited behavior or characteristic that enables an organism to survive & reproduce.
Adaptations can involve body parts or structures, like a tiger’s claws; colors, like those that make camouflage or mimicry possible; or physiological functions, like the way a plant carries out photosynthesis. Many adaptations also involve behaviors, such as the complex avoidance strategies prey species use.
Evolution will be discussed in greater detail in Unit 6.
https://www.youtube.com/watch?v=umQAdgIQ56A
Is There Evidence for Evolution (1:39)
Adults don’t always look like the babies of a species. All organisms begin their lives as a single cell. Over time, these organisms grow and take on the characteristics of their species. Growth results in an increase in the amount of living material and the formation of new structures.
All organisms grow, and different parts of organisms may grow at different rates. Organisms made up of only one cell may change little during their lives, but they do grow. On the other hand, organisms made up of numerous cells go through many changes during their lifetimes. Think about some of the structural changes your body has already undergone in your short life. All of the changes that take place during the life of an organism are known as its development.
A snowball grows when you roll it over fresh snow! Why isn’t it a living thing? The growth of the snowball is not internal. Someone has to roll the snowball. It won’t grow bigger by just sitting there and it certainly cannot change liquid water or solid ice into new snow from which it can grow larger. This is one of the differences between growth of a living thing and growth of a nonliving thing.
Lets add some vocabulary terms to our unit. Biotic means that it is living (or once living…dead)…so it exhibits all 8 characteristics of life. There are some things that have the POTENTIAL for life so are considered living…such as seeds, nuts, and eggs. These things could have all the characteristics of life under the right conditions.
Abiotic means that it was never living, or nonliving. Fire is abiotic. It may respond, grow, and reproduce…but it is not made of cells so it is considered abiotic.
