hello there eighth grade science students this is mrs geiss and can you believe it we have made it to the end of the year guys we have learned all of the new material that we were supposed to learn this year and now it is time to start preparing for the eog the eog for eighth grade will be on friday may 28th so we've got some time to prepare and we have a special learned notebook for you to help you with preparing to take the eog so go ahead and take out your 8th grade science review eog notebook and it is pink purpley color and let's go ahead and get started here we go so in this review we're going to cover all of the things that we have talked about this year with the standards listed up here at the top this unit review is not in the same order that we learned things this year okay just wanted to let you know that but we'll be covering properties of matter including elements and compounds mixtures physical and chemical changes and conservation of matter we'll be talking about energy the unit we just finished including how we obtain energy non-renewable sources renewable sources and energy that we use for life in our cells the hydrosphere that was the unit we started way back at the beginning of the year including water on earth water systems safety and potability and water treatment earth's history we will be talking about earth planet earth rocks and fossils how we date rocks and fossils the method methods that we use and evidence that we have plate tectonics as well as changing life forms in our evolution and diversity of life unit we will be discussing geologic time evolution adaptations and how we classify organisms in our biotechnology we will be talking about dna and genetics tools of biotechnology the benefits of biotechnology and ethical issues health and disease including disease-causing organisms epidemics and pandemics something we all know all too well right food and energy and healthy practices ecosystems including abiotic and biotic factors resources and interactions energy flow and the cycling of matter all right let's begin open up your notebook to page four and we'll begin with properties of matter we know the atom is the smallest unit of an element it still has the properties of that element all matter is composed of atoms atoms have mass and occupy space atoms of the same element have the same properties let's look at this chart for a minute we have the three parts of the atom including the proton the neutron and the electron remember the proton has a positive charge it is located in the nucleus and its mass is measurable the neutron it has a neutral charge remember neutron neutral it is located in the nucleus so it's easy to remember new new new and its mass is also measurable the electron has a negative charge it's found orbiting the nucleus and it's mass it's so tiny that it has what we call a negligible mass an element we know that these are composed of only one kind of atom they may link with bonds to form molecules that means they're chemically combined they compose all substances on earth and their structure and atomic makeup determines the properties of different substances the molecule is the smallest unit of a compound a compound is two or more atoms chemically combined remember i taught you the trick ccc a compound is chemically combined it may only be broken down through a chemical reaction mixtures are composed of two or more different substances these substances keep their own individual properties they are combined which means they are physically mixed but they can also be separated either by filtration or evaporation we have two main types of mixtures homogeneous and heterogeneous a homogeneous mixture has particles of the same size an example would be a solution in a heterogeneous mixture we have particles of different sizes remember to think about homogeneous could be lemonade where it all looks the same heterogeneous would be salad dressing where you can look and see the different layers of the ingredients physical properties can be measured without changing chemical properties so some examples of physical properties are appearance solubility density melting point boiling point and so on a physical change is the change in energy related to either being a solid liquid or gas a phase change is the change in energy molecular interactions can change so for example a solid can melt to become a liquid a liquid can boil to become a gas and liquids can freeze to become a solid chemical properties these can only be observed by changing the chemical identity so for example we have chemical changes these occur in a chemical reaction this what happens is we have break the new bonds new chemical bonds are formed reactions change the atomic arrangement remember when we learned about balancing chemical equations right we're not creating or destroying any matter but we are rearranging the atoms rearrange to form new compounds chemical changes may cause bubbles odors the formation of a precipitate heat or a color change all of these indicate that you've had a chemical change occur all physical and chemical changes involve a change in energy chemical reactions this is the recombination of atoms to form new molecules so for example ch4 plus 202 this arrow tells us that a chemical reaction has occurred and the products are co2 and 2 h2o so we have methane combined with oxygen it gives us or yields carbon dioxide and water this side of the equation these are known as our reactants remember the rat model reactants arrow and then these are the products p for products the conservation of matter tells us that atoms in the reactants are rearranged to form the products so no mass has been created or destroyed in a closed system remember gases are not released to the atmosphere the mass of the products is going to equal the mass of the reactants the periodic table the elements arranged in a grid by dimitri mendeleev remember the horizontal rows are called periods there are seven of those the vertical columns are called groups there are 18 of those and they have similar properties here is a picture of our periodic table thanks to dimitri mendeleev okay so make sure to prepare for the eog that you are familiar with these groups you want to know for example you want to know that the alkali metals alkaline earth metals you want to know the transition metals you want to know the halogens and the noble gases you want to know that these are the categories because when you are given a periodic table on the eog it will not have any answer key with it okay you just have to know that they are grouped in columns according to their similar properties all right let's look at each box each square in the periodic table we know that the large letter is the element symbol the number at the top is the atomic number which is the number of protons in the nucleus this is how the periodic table is arranged by the atomic number so if we go back we start with element number one here we have hydrogen and then we read it across this way helium is number two that means hydrogen has one proton in the nucleus helium has two then we go to lithium beryllium boron carbon and so on this number here is i'm sorry this number at the bottom is the mass number that is the atomic mass of that element and then here usually we will have the element name if you can't remember what the symbol stands for don't worry there's your element name the following chart highlights the major properties of metals metalloids and non-metals in the periodic table so metals they are we have the reactivity we have reactive metals and less reactive metals these conduct electricity and heat and are found in groups one and two the less reactive metals conduct electricity and heat and some examples would be the transition metals metalloids are sometimes reactive they are fair conductors of electricity which means they're not the greatest boron and silicon would be examples of metalloids non-metals are highly reactive they are a we have highly reactive ones and non-reactive ones excuse me the highly reactive ones are poor conductors of electricity they would include examples of chlorine fluorine and oxygen the non-reactive non-metals are poor conductors of electricity for as well and those would be helium and neon all right our next topic is energy energy is on page six energy is the ability to do work why is this important well we have many different types of energy many different forms of energy mechanical energy chemical energy thermal energy electrical energy nuclear energy and electromagnetic energy energy cannot be destroyed it just gets moved somewhere else the law of conservation of energy is very similar to the law of conservation of mass or matter right matter or mass can never be created or destroyed it just gets rearranged the same thing with energy it cannot be created or destroyed it just gets moved somewhere else often energy is lost in the form of heat from transfers and transformations transfer one form of energy is moved to an object as the same form so an example kicking a soccer ball the mechanical energy from your leg is moved to the mechanical energy in the ball transformation is when we have one form of energy is converted to a different form so for example chemical energy stored in a battery is transformed to mechanical energy in a remote control toy car humans use large amounts of energy to fuel our modern life and our conveniences this increased need for energy due to advanced technology and mass markets is something we have discussed a lot in class different types of fuels have different environmental impacts think of some examples we talked about them in class renewable energy versus non-renewable energy what impact do they have on the environment how reliable are they non-renewable energy used more quickly than can be made or produced what are some examples remember we discussed fossil fuels such as natural gas and petroleum and coal we also talked about nuclear energy nuclear energy is considered non-renewable because of its dependence on uranium disadvantages someday they could run out right it is expensive to obtain them and burning fossil fuels causes higher levels of pollution renewable energy can be produced or harnessed without much limit what are some examples wind solar biomass geothermal hydropower advantages many of these are available indefinitely right we're not going to run out of them they cause zero or limited pollution an example using hydropower sometimes means taking up a large area of land and possibly disrupting habitats that is a disadvantage it's important to remember that renewable energy sources do have disadvantages as well they are costly and can be hard to efficiently harness the energy or store it also remember they rely on ideal conditions if you're relying 100 on solar power it's not going to work at nighttime or on cloudy or rainy days solar energy is harnessed from the sun the sun has more energy than the earth even needs but it is difficult to capture and store it the following tools transform solar energy into electric energy the photovoltaic cell this changes light to electric energy the light causes electrons to move causing an electric current the solar battery stores energy from the photovoltaic voltaic cells the solar reflector concentrates solar rays to make an electric current we imitated this when we made our solar ovens using a pizza box tin foil black paper and saran wrap solar reflectors and solar energy can be used for industrial purposes confining or trapping solar energy presents challenges though it is possible to heat water by passing it through collectors and keeping it in isolated containers for example it's a great way to heat water for a house think about how this might work the hydrosphere go ahead and turn your page in your notebook to page eight water we know is has the chemical formula h2o it is one of the most common substances on planet earth it is circulated by a process known as the water cycle water is a solvent that means it dissolves minerals and gases to transport to oceans surface water moves into river basins from watersheds the water cycle recycles water over the entire earth remember water is matter matter can never be created or destroyed and we see this in the water cycle let's talk about the different parts or the different phases of the water cycle we have evaporation where liquid changes into a gas when it's exposed to heat this moves water into the atmosphere transpiration occurs in plants water is released into the atmosphere through the pores of the plants this moves water into the atmosphere condensation is when gas changes to a liquid so for example up in the clouds right they become too full they are they need to precipitation happens so that the water can fall back to earth evaporated water condenses and it turns into precipitation precipitation is when the water actually does fall to the earth in the form of rain snow sleet hail etc the effects is it remains on the surface or underground most rain and over half of earth's oxygen comes from the ocean aquatic life is extremely dependent upon energy ocean life includes food webs from microbes to large carnivores remember salinity measures the level of salt in the water so solidity salt that's a good way to remember salinity erosion volcanoes reactions at the sea floor and the atmosphere all can cause salinity to increase marine ecosystems remember i told you when you see the word marine i want you to think of salt water ocean ecosystems okay marine ecosystems we have the shore the open ocean and the deep ocean we have different zonation patterns caused by the tides waves and predation this influences life distribution the location and availability of life most of life in the ocean includes microbes in the form of algae they are our primary producers in the ocean they are the most abundant life form found in the ocean and they produce oxygen and food water and aquatic life make resources available upwelling occurs when an ocean current for example colder nutrient-rich waters rise up important this is extremely important for marine life in the ocean do you remember why remember many ocean uh fish marine mammals will actually migrate to off off the coast of new england in the summer off of the east coast in the atlantic because of the amount of upwelling right those offshore breezes i'm sorry the shore the breeze is coming off the shore blowing that water farther out to sea causes the colder nutrient-rich water to upwell from the bottom and it provides a perfect smorgasbord of feeding for a lot of different animals water in north carolina so we researched river basins of north carolina and the and these are the estuaries to which they and excuse me the estuaries to which they drain into as well as some of the lakes of north carolina remember we talked about the noose river basin pamlico sound cape fear river and river basin lake norman and lake mata mosquit the health and water safety are an important part of the hydrosphere we have physical chemical and biological variables so physical includes temperature turbidity remember how cloudy or clear the water is and the movement of water chemical variables include dissolved oxygen levels salinity levels nitrates how many nitrates are present remember nutrification and the ph level biological variables include habitats population and diversity what is a bioindicator remember it's a living organism that indicates the health of the water system bio indicators show water quality including water flow pollution and vegetation some bio indicators are very sensitive and will not be present if pollution is present let's look at some important events in the the hydrosphere unit that we discussed in 1914 drinking water standards for wells to test for coliform a deadly bacteria became more more and more present in our nation in 1940 drinking water standards for city water became implemented in 1970 the focus on harmful effects of pollution including aeration flocculation and carbon absorption were studied in 1972 we had the clean water act became law in the united states the 1974 the safe drinking water act became law in the 1980s we became more adept at using reverse osmosis excuse me reverse osmosis as a water purification technique this is especially important in areas uh coastal areas where salt water where the water table is oftentimes infiltrated by salt water and in 1990 risk asset assessments the right to safe drinking water became more the norm as we realize the importance of having safe drinking water for everyone in our country and our world earth history we are now on page 10. let's go ahead and dive in the study of the history of the earth has led scientists to many discoveries about life including the earth's composition it is composed of layers that provide evidence about earth history the crust is the outermost part of the list it's the outermost and part of the lithosphere the mantle is the middle part it includes magma and convection and the core has the is the innermost part and it is has iron and nickel present here you can see oops excuse me here you can see the different parts of the earth a fault is a dislocation in a break of the crust this is caused by the shifting of the crust fault types include movement from pressure along faults and may cause earthquakes one side of fault could of the fault could move up one side of the fault could move down plates can slide past each other sideways how does this relate to earthquakes how does an earthquake occur rocks break rock breaks along a fault releasing energy into the form of seismic waves this is what causes the ground to quake the rocks of earth provide insight to earth history they may use absolute or radioactive or even relative dating to determine the age of the rock igneous rock is made from molten materials on or below earth metamorphic rock is made from a change in one type to another sedimentary rock is made from deposited sediments or minerals sediments and remains of organisms are deposited and merged together forming solid rock or fossils this is where we find fossils fossils show how life and earth has changed over time remember our geologic timeline the law of superposition tells us that older rock is found below younger rock in sedimentary rock this is known as relative dating you are looking at how old a rock is in comparison with other rocks or fossils more recent fossils are found in shallower rock layers indicating more recent species older fossils are found in deep rock layers usually showing older species the most recent layer may not always be on top because of folding and breaking occurring the geologic time scale describes the history of earth beginning with the earth's formation the divisions of time there are four major divisions used to organize our earth history the eon the longest division of time there are four total eons era is the division of an eon split by mass extinctions the period is the division of an era shown by rock layers and the epoch is the division of a period the smallest division here are some examples we have the eon would be phenerozoic the era eon phanerozoic the era cenozoic the quaternary period and the halocene epoch dating methods we have two methods that help us determine age of rock and geologic events these are relative and absolute dating relative dating relative equals superposition absolute would be carbon 14 or radioactive uranium mildly radioactive breaks down at a steady rate this allows scientists to estimate the age of the earth which is about 4.6 billion years old give or take a few 100 million years earth history provides evidence such rocks fossils ice cores and geological data so rocks and fossils give us relative history of life ice cores give us evidence of earth's atmosphere and plant life geological dating uses techniques to infer age and history diversity of life on page 12. earth history provides evidence for gradual changes of living and non-living things the theory of evolution tells us a gradual change in a species over time based on natural selection remember our study of darwin and his finches and other organisms plate tectonics theory this is the movement of plates that give evidence of earth's changing format for example mountains trenches the law of superposition tells us that older rock is found below younger rock and gives relative ages biological evolution throughout earth's history organisms that were best adapted survived and were able to pass on their genes to their offspring adaptation remember that it's a beneficial trait that increases survival or reproductive success in a species changes to earth and their effects on biological evolution so we've had sea level changes the change in the continental shelves seas landforms land volume ice caps etc plate movements contribute to these sea level changes changes in climate and geography living things evolve in response to changes biological evolution leads to genetic diversity differences among organisms beneficial for continuation changes in phenotype gives the greater chance of survival similarities among organisms may indicate related species so look at this chart we have evidence description and significance so we know that homologous structures are structures from the same tissue types but used differently in different organisms they have anatomical similarities analogous structures are similarly similarly formed structures that do not share the same evolutionary origin they have cellular and anatomical evidence embryology or the study of embryos of different species different species showed striking similarities as developing embryos as you will see in the next slide they have a shared embryological characteristics as evidence fossils are preserved remains of once living organisms these indicate evolutionary changes throughout history and then we have dna evidence dna based sequences are most more similar in closely related organisms the significance is the degree of relatedness so look at the similarities in these structures we have it looks like a human a dog a whale and a bat look at these embryos we have a turtle a fish and a human at this stage of development they look strikingly similar so classification this is the science of grouping organisms based on shared characteristics we call this science taxonomy the diversity of life no two organisms have the same genetic code your dna is different from all other humans the only exception to this is identical twins identical not fraternal many beneficial adaptations allow living organisms to be incredibly diverse think about why is this important research at least three adaptations that have allowed organisms to evolve and to be more successful over time and use this information to fill in the chart on page 13. think about the finch speaks that we studied with darwin and his work in the galapagos islands all right biotechnology that was an exciting unit let's go ahead and turn to page 14 for biotechnology biotechnology is a rapidly growing field involving the use of living organisms to modify genes biotechnology has given us advances in medicine food genetics and agriculture in order to understand how biotechnology works you must understand dna we know dna which stands for deoxyribonucleic acid is the blueprint for life it contains all the genetic information for life here is a model of dna do you remember the parts remember we made 3d dna in class together here we have our hydrogen bonded bases our base pairs our sugar phosphate backbone right and remember adenine thymine cytosine guanine those are the parts right there your traits and characteristics are determined by your genes dna makes up genes which code for traits all living organisms have dna and genes there we go parents transmit their genes to their children by producing sex cells known as gametes that contain half of their genetic information when fertilized with a gamete from the opposite sex a complete organism is formed here we have our sperm cell 23 chromosomes the haploid male gamete has one copy of each chromosome pair the cell is produced by meiosis it joins up with the egg cell it has 23 chromosomes the haploid female gamete has one copy of each chromosome pair the cell is produced by meiosis the fertilized zygote we have 46 chromosomes two haploid gametes fused to form one diploid cell the first cell of an organism this will divide by mitosis and then finally we have the blastocyst this is 46 chromosomes in each cell divides by mitosis to form an embryo within days and a fetus within weeks dna is manipulated using techniques in biotechnology to create a beneficial outcome for example in healthcare it is used to treat genetic disorders and certain diseases an example making penicillin to treat infections transgenic engineering to produce insulin from bacterial dna the human gene for insulin production is transferred into a bacterial plasmid dna which then allows the bacterial cell to produce insulin think of how is this beneficial new techniques are emerging to treat cancers and many inherited conditions cystic fibrosis and skids which is an immune deficiency or system disorder are just a few crime scene investigation remember we talked about forensic science in biotechnology that uses dna for testing and study of a crime scene it can exonerate or it can help to put criminals away agriculture is another area of biotechnology it is used to develop beneficial crops the resistance to frost or freezing and pests are important in agriculture because biotechnology is rapidly advancing many new careers are available benefiting the local economy can you think of some examples we discussed here in north carolina we have the research triangle park the area in durham and raleigh and chapel hill where scientists come from all over the world to study and make improvements in biotechnology many ethical issues surround the field of biotechnology which do you feel presents the largest challenge complete the diagram on page 15 by comparing the pros and cons of biotechnology there's a venn diagram health and disease we're getting to the home stretch guys only a couple more this one and ecosystems and then we're done with our review microbiology involves the study of microbes many of which cause infections and diseases this includes the study of bacteria parasites viruses fungi algae and protozoa all are living organisms except viruses so let's look at the microbe the description and some examples first of all we have viruses these are non-living they are capable of replicating inside host the host and spreading rapidly this would include aids influenza common the common cold chickenpox smallpox and of course the coronavirus bacteria these are living prokaryotic organisms and they cause infections they must be treated with antibiotics some examples rabies lyme disease bacterial meningitis leprosy i'm sure that many of you have had an infection at some time in your life and the doctor has prescribed antibiotics for you it's important to only take the antibiotics prescribed by your doctor for the length of time that your doctor prescribes them fungi these are spread easily in moist places and they interfere with normal body bodily functions for example ringworm and athlete's foot you may have experienced those unpleasant fungal infections parasites parasites feed off of a host often infecting them with harmful diseases or they cause the disease themselves african sleeping sickness would be an example of a parasite protozoa these are single-celled animal-like organisms that may be transferred by a vector such as a mosquito plasmodium causes malaria let's look at microscopic prokaryotic bacteria a disease any condition that disrupts the normal functioning of processes within an organism a pathogen is any disease causing microorganism or particle an infection occurs when any organism becomes contaminated by a disease-causing agent disease outbreaks may spread rapidly through populations epidemics are when we have large outbreaks that are not worldwide they occur in large populations so for example malaria is a threat in africa but not worldwide not globally a pandemic would be a large outbreak occurring globally such as the flu or the current coronavirus outbreak human health depends on a balanced diet and regular exercise food we know is needed for energy which types of food give you the most energy if you're an athlete you know that you eat certain types of foods before certain events they will give you quick energy or more sustained energy depending on your sport carbohydrates these are quick energy providers such as sugars and starches it is found in fruit pasta potatoes this gives us the quickest energy source for living things it is able to be metabolized and broken down to simple sugars for energy lipids these are long-term energy storage such as fats and oils needed these are needed by your body to regulate temperature compose cell membranes and protect your organs proteins are used for growth and repair these make up your tissues in your body and they are found in meats yogurt and eggs all provide calories which is food energy metabolism refers to the set of chemical reactions that break down food to store and to use energy food provides nutrients but it must be oxidized to carry out cellular respiration to make atp remember adenosine triphosphate the basal metabolic rate the bmr refers to the amount of energy needed to carry out the minimum tasks for survival energy use in the body is broken down as follows sixty percent is just for our basal metabolic rate just our basic energy are needed for our bodily functions okay 30 is our daily physical activities it's what's needed to get up out of bed to walk to take a shower to do all of the things that we do during the day and then 10 is needed for digestion and processing of food all right guys this is it our last unit in our review ecosystems we are on page 18 in our notebook let's begin ecosystems are affected by food water and shelter think about it what is a habitat right a habitat is a place where organisms live it is specialized for that organism organisms may compete for these resources such as food water and shelter if they are limited energy is needed to fuel all ecosystems and everything we've learned this year everything goes back to the sun right we can trace every single bit of energy or food web or food chain back to the sun this can change forms in living things energy can change forms in living things and food is oxidized energy is released as heat life relies on food webs there are two major food webs they begin with microscopic ocean producers which we know to be algae and on lamb it begins with terrestrial plants so aquatic food webs terrestrial food webs explain how food web functions in the space excuse me explain how a food web functions in the space provided on page 18. plants in an ecosystem they are known as producers they are the first step in a food chain or food web we call them autotrophs they make their own food they contribute to the energy flow and which and they exist at the bottom they are extremely important for all life so we take energy from the sun right the autotrophs take that energy they through photosynthesis are able to produce and give off glucose give out glucose produce glucose and oxygen heterotrophs these are consumers we have for example this rabbit is going to eat the grass and get its energy from the grass which got its energy from the sun the snake might eat the rabbit which got its energy from the grass which got its energy from the sun and then we have decomposers these break down matter these are they rely on dead and decayed material to get their energy so again autotrophs make their own food they get their energy from the sun and they provide energy for consumers the animals that consume them they have a role in transpiration they use and release moisture back into the environment and this is present in the water cycle they photosynthesize they are photosynthetic in addition to making their own food they also release oxygen into the atmosphere this provides oxygen oxygen for other living organisms animals in an ecosystem for example we have consumers they consume energy from other organisms they aren't can be heterotrophs they contribute to ecological balance such as competition cooperation predator prey relationships symbiosis and many others so let's look at consumers they depend on levels uh below for a source of energy they use food energy and provide it for higher levels they the coexistence that they exhibit is living together in the same sp same space the competition symbiosis predator prey relationship is all evident advanced organisms animals range in complexity from simple to very advanced each each single each organism has a role or a niche in life has an important role in life remember we call that the niche or the niche symbiosis is a close association between two different species mutualism for an example this is ants for example and acacia trees the ants get food and shelter the tree gets protection parasitism for example a tick and a dog the tick harms the host but does not kill it so mutualism is when both benefit parasitism is when one is harmed while the other benefits think about commensalism do you remember what commensalism is energy and matter move throughout ecosystems it can't be destroyed it's always recycled research each of the cycles below why are they significant to the functioning of ecosystems how do they represent recycling of materials water carbon nitrogen and oxygen here you have a diagram of the water cycle i would go ahead and label this and be familiar with the water cycle make sure you know all of the names such as evaporation condensation precipitation runoff collection and so on that is it guys i encourage you to look at your properties um excuse me your vocabulary list that beginning on page 20 and going in your notebook all the way through page 27 i also encourage you to look back at your notebooks that we've completed throughout this year please take time to review don't try to do it all the day before the eog that will not be helpful but if you do a little bit each day like maybe take two or three days to review terms from each of our units then you can relax and know that you'll be prepared for the eog thank you so much and have a great day and good luck on your test it's your time to shine