Objective 2 Living Systems & Environment Middle School Science Science 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!)

CELL THEORY 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.

Two Basic Types of Cells Eukaryotic – made up of cells that have a membrane covered nucleus Prokaryote – one-celled organism that does not have a nucleus – only bacteria

Cells Most basic part of a living system “Cells are Building Blocks” Cells contain organelles Animal & Plant cells both contain: nucleus- command center of the cell cell membrane- protective outer layer cytoplasm- gelatin-like substance that fills inside of cell (contains other organelles that are vital to the processes of life) mitochondria- to provide power for cell activities vacuole – holds waste products or substances needed by the cell

Only plant cells have cell walls for support & chloroplasts to carry out photosynthesis.

Levels of Organization

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. Feedback mechanism

Homeostasis Adaptations The 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. Adaptations What 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 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.

Natural Selection Process by which the characteristics that help a species to survive are passed on to the next generation.

Selective Breeding the process of breeding plants and animals for particular traits. 

Dichotomous Key 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".

A habitat is the specific place in which an organism makes its home. 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.

Organisms are affected by one another Organisms interact with their environment Each part of the community has its own function, but together they form the entire pond ecosystem. Organisms are affected by one another 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 from plants to animals through 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 consumers Herbivores- animals that eat only plants Carnivores- animals that eat only other animals Omnivores- animals that eat both plants & other animals

Predators Prey An animal that kills and eats other animals Organism that is killed and eaten by another organism

Parasite Host Organism that supports a parasite Organism, such as a tick, that feeds on cells, tissues, or fluids of another living organism (host) Parasite Organism that supports a parasite Host

Decomposers Fungi Bacteria 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. Fungi Bacteria

Biotic and Abiotic Factors 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 Web A complex system of energy flow through overlapping food chains. Energy passes in many different directions through all the organisms.

Succession Rebuilding of populations in a community or ecosystem that has been changed. 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.

Ocean Systems 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 Body The human body includes systems such as: Circulatory Respiratory Digestive Excretory Muscular Skeletal Nervous Integumentary Endocrine Reproductive http://www.kidshealth.org/PageManager.jsp?lic=1&article_set=29673&ps=110 http://www.innerbody.com/htm/body.html

Circulatory system Arteries are tubes that carry blood away from the heart Veins are tubes that return blood to the heart Capillaries connect arteries and veins. They are tiny tubes that exchange food, oxygen and wastes between blood and body cells.

Respiratory BREATH IN -- your body gets oxygen from the air. Rib muscles contract to pull ribs up and out. The DIAPHRAGM muscle contracts to pull down the lungs. Tissue expands to suck in air. BREATH OUT -- you get rid of other gases that your body does not need. Rib muscles relax. The Diaphragm muscle relaxes. Tissue returns to resting position and forces air out.

Digestive system Breaks down and absorbs food to provide energy for the body

Excretory Gets rid of body wastes and excess fluids

Muscles Muscle contracts to move bones and body parts Muscles look either striated or smooth: Striated muscle has stripes or striations in it. Smooth muscle does not.

Voluntary or Involuntary Muscles Voluntary muscles are muscles that you can move whenever you want to. Involuntary muscles contract and relax automatically inside your body. We can not control our involuntary muscles

Did you know????? There are more than 600 muscles in your body That nearly 35-40% of your body mass is muscle The smallest bones are in your ear. The largest bone, the femur, is found in your thigh

Skeletal system Function of bones protect internal organs support the body make blood cells store minerals provide for muscle attachment

Joints A point where one bone attaches to another bone. There are two different types of joints in the body: Movable joints (like ball-and-socket, hinge, gliding and pivot joints) Immovable joints (like the bones of the skull and pelvis) which allow little or no movement

Immovable joint Hinge joint Ball & Socket joint

Controls everything you do Nervous system Controls everything you do collects, transfers and processes information with brain, spinal cord, peripheral nerves, and nerves

Integumentary is the organ system that protects the body from damage, comprising the skin and its appendages (including hair, scales, feathers, hoofs, and nails).

Endocrine System is the system of glands, each of which secretes a type of hormone directly into the bloodstream to regulate the body

Reproductive System  a system of organs within an organism which work together for the purpose of reproduction.

Systems A group of parts that form a complex whole- work together to achieve goals that the parts could not reach alone. Parts can interact, be related to one another, or depend on each other. Example: Circulatory and Respiratory systems work together

Asexual Reproduction 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 Autotroph vs Heterotroph An organism, such as a plant, that makes its own food An organism that obtains the energy it needs by feeding on other organisms