Objective 2Objective 2Living Systems & Living Systems &
EnvironmentEnvironmentMiddle School ScienceMiddle School Science
Science STAAR Need to KnowScience STAAR Need to Know
All living things are made up of cells.
Unicellular (Single-celled)- organisms that are made up of only one cell.
Multicellular- organisms made up of many cells. (Some have billions & trillions of cells!)
•All living organisms are composed of cells. They may be unicellular or multicellular.
•The cell is the basic unit of life.
•Cells arise from pre-existing cells.
CellsCells Most basic part of a living systemMost basic part of a living system
““Cells are Building Blocks”Cells are Building Blocks”
Cells contain organelles Cells contain organelles Animal & Plant cells Animal & Plant cells bothboth contain: contain:
nucleusnucleus- command center of the cell- command center of the cell cell membrane-cell membrane- protective outer layer protective outer layer cytoplasmcytoplasm- gelatin-like substance that fills inside of cell - gelatin-like substance that fills inside of cell
(contains other organelles that are vital to the (contains other organelles that are vital to the processes of life)processes of life)
mitochondriamitochondria- to provide power for cell activities- to provide power for cell activities vacuolevacuole – holds waste products or substances needed – holds waste products or substances needed
by the cellby the cell
Only plant cells have cell walls for support & chloroplasts to carry out photosynthesis.
Prokaryote – one-celled organism that does not have a nucleus – only bacteria
Eukaryotic – made up of cells that have a membrane covered nucleus
Levels of OrganizationLevels of Organization
Feedback Feedback mechanismmechanism
A response of an organism to a given change, such as temperature or the amount of light.
Example: Sweating
If the body temperature gets too high, sweat glands open up, causing a person to sweat.
The sweat then evaporates, carrying heat energy away from the body. This cools the skin.
When the body temperature returns to normal, another nerve signal is sent out to close the sweat glands.
HomeostasisHomeostasisThe body has ways of adjusting to different conditions. Keeping conditions such as body temperature constant is called equilibrium or homeostasis. Equilibrium occurs when a system is balanced.
AdaptationsAdaptationsWhat if a change is too extreme & an organism can’t maintain equilibrium? The organism may die!!
However, most organisms are adapted to the environments where they live. Their body systems & behaviors adjust or change to allow them to survive in the new environment.
Genetic traitsGenetic traits
Genes- a segment of DNA on a chromosome that contains information for specific genetic traits. Genes are passed from parents to offspring.
Genetic trait- a characteristic passed on from a parent to offspring.
Genetic traits that help organisms to survive in their environment are called adaptations. Adaptations can be either physical characteristics or behaviors.
Process by which the characteristics that help a species to survive are passed on to the next generation.
the process of breeding plants and animals for particular traits.
A dichotomous key is a method for determining the identity of something (like the name of a butterfly, a plant, a lichen, or a rock) by going through a series of choices that leads the user to the correct name of the item. Dichotomous means "divided in two parts".
Ecosystem – includes the living & nonliving parts of an environment.
Nonliving- water, soil, light, air
Living- plants, animals & other living organisms (makes up the community)
Community – a group of different types or populations or plants, animals, & other organisms living & interacting with one another in an environment.
Each population in a community lives in a particular part of that environment called a habitat.
A habitat is the specific place in which an organism makes its home. As you move up the diagram,
each level is more complex.
Each part of the community has its own function, but together they form the entire pond ecosystem.
Organisms are connected by the energy that flows through the pond community. Both plants & animals require energy.
This flow begins with the plants using energy from the sun and continues through all the organisms in an ecosystem.
The variety of organisms in a
specific environment, or on Earth as a whole.
Plants change radiant energy from the sun into chemical energy.
Carbon dioxide and water are converted into sugar and oxygen.(Sugar is very important in an ecosystem- it’s food for plants & for other organisms. When plants are eaten, the energy in the plant matter is passed on to other organisms in the food chain.)
Chemical energy passes Chemical energy passes from plants to animals from plants to animals through a food chainthrough a food chain
Producers- (plants) organisms that make their own food
Primary consumers- animals that get their energy from eating plants
Secondary (second-order) consumers- animals that eat primary consumer animals.
Animals can be both a primary & secondary consumer.
Types of Types of consumersconsumers
HerbivoresHerbivores- animals that - animals that eat only plantseat only plants
CarnivoresCarnivores- animals that - animals that eat only other animalseat only other animals
OmnivoresOmnivores- animals that - animals that eat both plants & other eat both plants & other animalsanimals
An animal that kills and eats other animals
Organism that is killed and eaten by another organism
Organism, such as a tick, that feeds on cells, tissues, or fluids of another living organism (host)
Organism that supports a parasite
DecomposersDecomposers
Organisms that feed on dead plants & animals. This releases the chemical energy and nutrients in the dead plants and animals back into the environment.
Decomposers play an important role in recycling nutrients & energy.
Biotic factors are all of the living things in the community
Abiotic factors are essentially non-living components that effect the living organisms of a community.
Food Chain- shows the flow of energy from one organism to another to yet another.
Food WebFood Web A complex system of energy flow through overlapping food chains.
Energy passes in many different directions through all the organisms.
SuccessionSuccession
Succession can happen in any environment where change occurs.
Other examples: a plowed farm field, a burned forest, or a grassland that gradually receives less rainfall.
Rebuilding of populations in a community or ecosystem that has been changed.
• Affected by run-off of fertilizers and pollution• Artificial reefs used to create environments for different species• Most valuable natural resource
-provides food about 200 billion pounds are caught each year. - used for transportation—both travel and shipping. - provides a treasured source of recreation for humans. - is mined for minerals (salt, sand, gravel, and some manganese, copper, nickel, iron, and cobalt can be found in the deep sea)-drilled for crude oil. -plays a critical role in removing carbon from the atmosphere and providing oxygen. -- regulates Earth's climate.
Systems in the Human BodySystems in the Human BodyThe human body includes systems such as:The human body includes systems such as:
CirculatoryCirculatoryRespiratoryRespiratoryDigestiveDigestiveExcretoryExcretoryMuscularMuscularSkeletalSkeletalNervousNervous
IntegumentaryIntegumentaryEndocrineEndocrine
ReproductiveReproductive
Circulatory Circulatory systemsystem ArteriesArteries are tubes that are tubes that
carry blood carry blood awayaway from from the heartthe heart
VeinsVeins are tubes that are tubes that return bloodreturn blood to the to the heartheart
CapillariesCapillaries connect connect arteries and veins. arteries and veins. They are tiny tubes They are tiny tubes that exchange food, that exchange food, oxygen and wastes oxygen and wastes between blood and between blood and body cells. body cells.
RespiratorRespiratoryy BREATH IN -- your body gets oxygen from the air. Rib muscles BREATH IN -- your body gets oxygen from the air. Rib muscles
contract to pull ribs up and out. The DIAPHRAGM muscle contract to pull ribs up and out. The DIAPHRAGM muscle contracts to pull down the lungs. Tissue expands to suck in air. contracts to pull down the lungs. Tissue expands to suck in air.
BREATH OUT -- you get rid of other gases that your body does BREATH OUT -- you get rid of other gases that your body does not need. Rib muscles relax. The Diaphragm muscle relaxes. not need. Rib muscles relax. The Diaphragm muscle relaxes. Tissue returns to resting position and forces air out. Tissue returns to resting position and forces air out.
Digestive Digestive systemsystem
Breaks down and Breaks down and absorbs food to absorbs food to provide energy provide energy for the bodyfor the body
ExcretoryExcretoryGets rid of body wastes Gets rid of body wastes
and excess fluidsand excess fluids
MusclesMuscles
Muscle contracts to move bones and body parts Muscle contracts to move bones and body parts Muscles look either striated or smooth: Muscles look either striated or smooth:
StriatedStriated muscle has stripes or striations in it. muscle has stripes or striations in it.
SmoothSmooth muscle does not. muscle does not.
Voluntary or Involuntary Voluntary or Involuntary MusclesMuscles
VoluntaryVoluntary muscles are muscles that muscles are muscles that you can move whenever you want to. you can move whenever you want to.
InvoluntaryInvoluntary muscles contract and muscles contract and relax automatically inside your body. relax automatically inside your body. We can not control our involuntary We can not control our involuntary musclesmuscles
Did you know?????Did you know?????
There are more than 600 muscles in There are more than 600 muscles in your bodyyour body
That nearly 35-40% of your body That nearly 35-40% of your body mass is musclemass is muscle
The smallest bones are in your ear. The smallest bones are in your ear. The largest bone, the femur, is found The largest bone, the femur, is found in your thighin your thigh
Skeletal systemSkeletal system
Function of bonesFunction of bones protect protect internal organs support the body support the body make blood cells make blood cells store minerals store minerals provide for provide for muscle
attachment attachment
JointsJoints
A point where one bone attaches to A point where one bone attaches to another bone. another bone.
There are two different types of joints in the There are two different types of joints in the body:body:
Movable jointsMovable joints (like (like ball-and-socket, , hinge, , gliding and pivot joints) and pivot joints)
Immovable jointsImmovable joints (like the bones of (like the bones of the skull and the skull and pelvis) which allow little or no ) which allow little or no movement movement
Nervous systemNervous system
collects, transfers and processes information with brain, spinal cord, peripheral nerves, and nerves
is the organ system that protects the body from damage, comprising the skin and its appendages
(including hair, scales, feathers, hoofs, and nails).
is the system of glands, each of
which secretes a type of hormone directly into the bloodstream to
regulate the body
a system of organs within an organism which work together for the purpose of reproduction.
SystemsSystems A group of parts that form a complex A group of parts that form a complex
whole- work together to achieve goals whole- work together to achieve goals that the parts could not reach alone.that the parts could not reach alone.
Parts can interact, be related to one another, Parts can interact, be related to one another, or depend on each other.or depend on each other.
Example:
Circulatory and Respiratory systems work together
Type of reproduction by which offspring arise from a single parent, and inherit the genes of that parent only
An organism, such as a plant, that makes its own food
An organism that obtains the energy it needs by feeding on other organisms