8th grade Science Final

Question 1

What is a Fossil?

Answer 1

Evidence That an Organism Lived

Question 2

How do fossils show how organisms have evolved through time?

Answer 2

Characteristics or Anatomy

Question 3

How do fossils provide evidence of environmental changes that occurred in the past?

Answer 3

Physical characteristics can tell what the environment that they lived in was like.

Question 4

What are the different types of divisions of geologic time?

Answer 4

Eons, Eras, Periods, Epochs.

Question 5

How do the ages of the oldest fossils compare to the age of the Earth?

Answer 5

3.6 BYA (the earth is 4.6 billion years old)

Question 6

What evidence can scientists use to study Earth’s history?

Answer 6

Rock Strata. We look at the geologic record.

Question 7

What two methods do scientists use to determine the ages of rocks?

Answer 7

Relative and Absolute dating.

Question 8

How are geologic principles applied to understanding Earth’s history?

Answer 8

Uniformaritarism (process of the past happen the same way in the past as now. ex- Volcanoes erupt the same way they did in the past)

Question 9

What is a watershed and what are the major watersheds in your state?

Answer 9

A watershed is all of the land area that drains into a river system. Hiwassee, Savannah, Little Tennessee, French Broad, Broad, Watauga, New, Catawba, Yadkin-Peedee. Roanoke, Cape Fear, Lumber, Neuse White Oak, Tar-Pamlico, Chowan and the Pasquotank are the watersheds in our state.

Question 10

What are the components and characteristics of a river system?

Answer 10

A river system includes a major river and all of its tributaries. A tributary is a stream or creek that feeds into a river. The river system also includes the watershed from which runoff drains into the rivers and tributaries. Rivers that drain into oceans also include estuaries—areas where freshwater from the river mixes with saltwater from the ocean. Wetlands are saturated areas of low elevation that typically surround a river’s mouth.

Question 11

Why are wetlands important?

Answer 11

Wetlands provide important functions in a river system, including regulating runoff by storing water; reducing erosion by slowing runoff; maintaining water quality by filtering sediments; trapping and breaking down nutrients; and recharging groundwater. Wetlands are important to biological communities as well. They provide food and shelter for wildlife, as well as nesting and resting areas for migratory birds.

Question 12

Why are estuaries important?

Answer 12

Estuaries provide important habitats for many aquatic organisms, including fish, shellfish, and aquatic mammals. Estuaries serve as breeding grounds and nurseries for many animal species.

Question 13

How can the water quality in a watershed be affected by human activity?

Answer 13

The water quality in a watershed can be negatively affected by pollutants in the watershed that wash into the river system. Human development that includes cutting vegetation and paving areas can impact water quality by increasing erosion and decreasing the ability of wetlands to perform their important ecological functions.

Question 14

How do scientists study the oceans?

Answer 14

Scientists divide the ocean into layers. The layers are classified according the depth, the amount of light the layer receives, and what types of organisms live there. The sunlight zone, or the epipelagic zone, is the top layer of the ocean. It is a warm layer that has a lot of mixing due to currents and wave action. The sunlight zone is the only zone of the ocean that has water plants, such as sea grasses and kelp. This is because the lower layers do not receive enough sunlight for photosynthesis. The twilight zone, or the mesopelagic zone, has some light that passes through it, but does not have enough to support plant life. This zone is colder and denser than the sunlight zone. This layer is less diverse than the zone above it, but it still has quite a number of organisms, some with unique characteristics. Animals that live in the twilight zone may have a characteristic called bioluminescence, which means that they chemically make their own light. The midnight zone, or the bathypelagic zone, is the next zone in the ocean. This zone completely black at all times. Animals in this layer can withstand high pressures and extremely cold temperatures. The abyssal zone, or the abyssopelagic zone, is the zone that reaches the ocean floor. There are crushing pressures in this layer and the temperatures are near freezing. Surprisingly, life can be found at this layer. There are several animals that thrive near deep sea vents, feeding on bacteria and the sulfur that is released from the vents. Finally, the hadal zone, or the zone that is in ocean trenches, the least explored layer of the ocean. The depth, pressure, and temperatures are hostile to many creatures. Very few organisms live at these depths.

Question 15

What role do the oceans play in weather and climate?

Answer 15

Convection Currents (Cooling, Rising, Heating, Sinking)

Question 16

How do we use the ocean as a resource?

Answer 16

The ocean provides numerous resources and is of great economic importance to humans. Algae from the ocean is used as a thickener or binder in many things we use every day, such as shampoo, soaps, yogurt, milk, medicine capsules, etc. We also get compounds used in some very important cancer drugs from corals and sponges that live in the ocean. Fishing is a livelihood for many and provides food. The ocean floor is also mined for oil and gas deposits, providing energy for heat and transportation. Sometimes, this mining can cause enormous devastation, however. The Deepwater Horizon explosion and resulting oil spill in the Gulf of Mexico in 2010 was the worst on record, killing people and animals, damaging estuaries, and causing strange mutations in local fishing beds.

Question 17

How can physical and chemical factors, such as temperature, dissolved oxygen, pH, salinity, turbidity, and nitrates be used to determine the health of an aquatic ecosystem?

Answer 17

Physical and chemical parameters can tell us about the health of an aquatic ecosystem. Healthy waterways will have normal ranges for temperature, DO, pH, and so on. When we measure these things, we can begin to see what the normal range is, and can tell when the waterway is not normal. Fluctuations in the parameters can tell us if the health of the aquatic ecosystem is changing.

Question 18

What can bioindicators, such as the number and types of macroinvertebrates, reveal about the health of an aquatic ecosystem?

Answer 18

In general, the greater the diversity of biological species, the better the health of the stream. The presence of macroinvertebrates indicates that the stream is healthy enough for them to live. If there are only a few, or if the species present thrive in adverse conditions (for example, in low oxygen levels), then we know that there might be problems with the water quality. In addition to macroinvertebrates, it’s also important to look at the overall diversity of living things in the waterway, such as fish, aquatic plants, and so on.

Question 19

How do scientists classify organisms?

Answer 19

Scientists use common features to place organisms into categories.

Question 20

What are some common features that scientists use to classify organisms?

Answer 20

Scientists may use physical features to classify organisms. For example, similar organisms may have similar respiratory(gills or lungs) systems or skeletal structures. Scientists may also use behaviors to classify organisms. For example, similar organisms may have similar reproductive methods. Anatomy

Question 21

What is the Linnaean system of classification?

Answer 21

The Linnaean system of classification places organisms into groups based on their shared characteristics. These groups include Domain, kingdom, phylum, class, order, family, genus, and species. These groups are hierarchical. This means that kingdom is the largest group and species is the smallest groups. The other groups fall between kingdom and species.

Question 22

What nonliving substances are important to living organisms?

Answer 22

All organisms need water to survive. Plants require carbon dioxide for photosynthesis. Organisms that do not photosynthesize, like animals, need oxygen for cellular respiration. Most organisms require nitrogen to grow and survive. These substances are constantly cycled between living organisms and the non-living environment.

Question 23

What is the difference between an ecosystem, a habitat, and a niche?

Answer 23

An ecosystem includes a set of populations that are adapted to survive in that ecosystem and the non-living environment that surrounds them. A habitat is the particular place in which a particular organism lives. An organism’s niche is defined by the unique role it plays in its environment. (Niches are in Habitats and Habitats are in Ecosystems)

Question 24

How do different organisms in a community obtain energy from their environment?

Answer 24

Photosynthetic organisms such as plants obtain energy directly from the sun. They are called producers. Herbivores are organisms that take in that energy by eating plants and other photosynthetic organisms. Herbivores are considered primary consumers. Carnivores are organisms that take in energy by eating animals. Carnivores can be secondary and tertiary consumers. Omnivores are animals that eat both plants and animals. Decomposers get energy from dead plants and animals and other organic matter.

Question 25

What kinds of relationships exist between organisms in a community?

Answer 25

Relationships in a community can be cooperative or competitive. Predator/prey relationships and parasite/host relationships are competitive relationships. In a predator/prey relationship, a predator hunts prey for food. In a parasite/host relationship, a parasitic organism feeds on a living host organism in order to survive. Sometimes this kills the host organism. Symbiosis is a kind of cooperative relationship. In symbiotic relationships, organisms work together to obtain energy from their environment, grow, and reproduce.

Question 26

Why is the sun an important source of energy for all living things?

Answer 26

The sun continuously supplies energy into nearly every ecosystem on Earth. Producers store this energy in matter. Energy and matter are transferred from producers to consumers, from consumers to other consumers and to decomposers, and from decomposers to other organisms, in a cycle. In this cycle, matter and energy are conserved. However, much energy is lost into the environment every time an energy transfer between organisms occurs. Energy that is released into the environment can no longer be used by living things. Without the sun, there would be no way to replace energy released into the environment.

Question 27

What is a trophic level?

Answer 27

A trophic level is a set of organisms who all have similar nutritional needs. In a food web, secondary consumers, such as fox and birds of prey, are on the same trophic level.

Question 28

How do different populations from the same trophic level interact?

Answer 28

Different populations on the same trophic level can compete for food. Competition for food and other resources can limit the size of the populations involved.

Question 29

How do populations from different trophic levels interact?

Answer 29

Organisms in a single ecosystem are all part of the same food web. When the number of organisms in population changes, the entire food web is affected. A change in population size at the lower trophic levels of a food web often has the most marked q on the rest of the food web. Sometimes populations from different trophic levels can work together to survive in an ecosystem. For example, the relationship between bees, which are primary consumers, and flowering plants, which are producers, is a symbiotic relationship where the bees obtain food from the flowering plants, and the plants use the bees as pollinators. This is called mutualism, because both organisms benefit from the relationship.

Question 30

What is genetic variation and how does it help a population to survive?

Answer 30

Organisms have features that allow them to survive in the environment. Over time, environments change. Organisms with features that give them a competitive advantage in the changed environment survive. These features are called adaptations. VARIATIONS ARE IN SPECIES

Question 31

How do populations benefit from individual adaptations?

Answer 31

Organisms with beneficial adaptations are more likely to survive and reproduce. Their offspring will have some of the parent organism beneficial adaptations. Over time, the number of organisms in a population with the beneficial adaptation will increase. This is called natural selection. Natural selection leads to evolution. (Survival of the fittest)

Question 32

How do organisms survive in a changing environment?

Answer 32

Genetic variation refers to how similar or different the members of a same species are to one another. If members of a species are very similar to one another, then they are less likely to adapt to a changing environment. This is because there is less of a chance that individual organisms will have the features needed to survive in a new environment. Sexual reproduction increases diversity which helps with variations. ADAPTATION

Question 33

Why does overpopulation occur?

Answer 33

Usually, populations of organisms are kept in check by the availability of resources such as water, food, and shelter and by predation and disease. However, if changes occur that alter these factors, overpopulation can occur. Overpopulation occurs when the number of organisms located in an area cannot be supported by the local resources. In human populations this happens when technologies allow for an increased level of food production, an increase in the quality of sanitation, and a resulting decrease in the rate of death from disease. HABITAT LOSS, OVER COMPETITION FOR FOOD SOURCES CAUSING LOW FOOD SOURCES, THEN SPECIES STARVE OUT.

Question 34

What problems does overpopulation cause?

Answer 34

Overpopulation can cause organisms to have more difficulty surviving because of the scarcity of resources. When this happens, the size of the population decreases until the number of surviving organisms can once again be supported by the environment. If resources are completely exhausted because of overpopulation, then all of the organisms in the population can die.

Question 35

How can overpopulation be reduced?

Answer 35

Overpopulation can be reduced as individual organisms or groups of organisms migrate to other places. These organisms will start new populations, which will increase in number until further increases cannot be supported by the available resources.

Question 36

How does energy flow through ecosystems?

Answer 36

Energy flows through ecosystems in the form of food.

Question 37

Why is food important to organisms?

Answer 37

Food provides the fuel and the building material for all organisms.

Question 38

Why are all organisms connected to each other?

Answer 38

All organisms, including the human species, are part of and depend on the global interconnected food webs of the ocean and the land.

Question 39

What is the carbon cycle?

Answer 39

The carbon cycle is the movement of carbon between living systems and their physical environment through the processes of photosynthesis, respiration, decomposition, burning, and absorption, among others.

Question 40

Conditions to fossils

Answer 40

If it has hard parts, covered quickly, free from microbes.

Question 41

Types of fossils

Answer 41

trace, petrified remains, carbonaceous films, molds and casts, original remains
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