TAKS objective 2 Living Systems & environment

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TAKS objective 2 TAKS objective 2 Living Systems & Living Systems & environment environment Middle School Science Middle School Science Science TAKS Need to Know Science TAKS Need to Know

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TAKS objective 2 Living Systems & environment. Middle School Science Science TAKS Need to Know. All living things are made up of cells. Unicellular (Single-celled)- organisms that are made up of only one cell. - PowerPoint PPT Presentation

Transcript of TAKS objective 2 Living Systems & environment

Page 1: TAKS objective 2 Living Systems & environment

TAKS objective 2TAKS objective 2Living Systems & Living Systems &

environmentenvironmentMiddle School ScienceMiddle School Science

Science TAKS Need to KnowScience TAKS Need to Know

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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!)

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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

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

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Animal Animal CellCell

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Plant Plant CellCell

Contain 2 organelles that animal cells do not have:

*Chloroplasts- use sunlight & CO2 to create food for the plant’s cells

*Cell wall- rigid structure that provides protection and support for plant cell

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Systems work together to carry out various life functions.

Example:

A track runner has different systems that work together:

-Muscles move the arms & legs. This uses up oxygen, which must be provided through the bloodstream.

-The heart starts beating faster to move more blood to the muscle cells that need oxygen.

-As breathing rate increases, the lungs have to take in oxygen & get rid of carbon dioxide more quickly.

-The brain sends signals to the lungs, heart, & muscles to coordinate all these activities.

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Levels of OrganizationLevels of Organization

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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.

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Cells, Tissues, Organs, Organ SystemsCells, Tissues, Organs, Organ SystemsWhen you breathe, cells in your lungs help move oxygen into your bloodstream. Many of these cells together form an air sac, which is a kind of lung tissue. These & other tissues together form a lung, which is an organ. The mouth, nose, & trachea are other organs that work together with the lungs to help you breathe. These are some of the organs that make up the respiratory system. The respiratory system is just one of the many organ systems in the whole human organism.

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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.

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ExtinctionExtinction

The loss of an entire species is called extinction.

Example:

If an organism doesn’t have adaptations that allow it to live in a colder climate, then it must move to a warmer environment or it will die. This can affect single organisms as well as whole populations.

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Genetic traitsGenetic traitsGenes- 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.

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How are genes passed How are genes passed from parents to from parents to offspring?offspring?

During reproduction, the parents’ genes in the sex cells (egg & sperm) will create the new organism. This is called sexual reproduction.

In sexual reproduction, both parents pass the genes for traits on to their offspring. Half the genes come from the male and half come from the female.

Sexual reproduction results in genetic diversity due to the large number of gene combinations that may occur.

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Genes combine to produce different traits

Each parent has genes that occur in pairs and, due to the production of the special sex cells, only one of the alleles of a gene pair will be in each sex cell. Alleles are forms of the same gene. So the offspring receive one allele of a gene from the mother and one from the father.

Alleles occur in two forms: dominant and recessive.

If a dominant allele of a gene is present, the dominant trait will appear in the organism. A capital letter is used to show a dominant allele.

For a recessive trait to be expressed, both alleles of the gene must be recessive. A lowercase letter is used to show a recessive trait.

A pea plant will have purple flowers if it receives a dominant allele from one or both parents (Pp or PP). A plant will have white flowers only when both parents contribute an allele for the recessive trait (pp).

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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.

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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.

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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.)

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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.

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Animals can be both a primary & secondary consumer.

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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

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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.

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Food Chain- shows the flow of energy from one organism to another to yet another.

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Food WebFood Web A complex system of energy flow through overlapping food chains.

Energy passes in many different directions through all the organisms.

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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.

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Systems in the Human BodySystems in the Human BodyThe human body includes systems such as:The human body includes systems such as:

CirculatoryCirculatoryRespiratoryRespiratoryDigestiveDigestiveExcretoryExcretoryMuscularMuscularSkeletalSkeletalNervousNervous

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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.

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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.

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Digestive Digestive systemsystem

Breaks down and Breaks down and absorbs food to absorbs food to provide energy provide energy for the bodyfor the body

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ExcretoryExcretoryGets rid of body wastes Gets rid of body wastes

and excess fluidsand excess fluids

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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.

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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

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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

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Skeletal systemSkeletal systemFunction of bonesFunction of bones protect protect internal organsinternal organs support the body support the body make blood cells make blood cells store minerals store minerals provide for provide for musclemuscle

attachment attachment

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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-socketball-and-socket, ,

hingehinge, , glidinggliding and pivot joints) and pivot joints) Immovable jointsImmovable joints (like the bones of (like the bones of

the skull and the skull and pelvispelvis) which allow little or no ) which allow little or no movement movement

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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