8th grade Science Final Flashcards
(41 cards)
What is a Fossil?
Evidence That an Organism Lived
How do fossils show how organisms have evolved through time?
Characteristics or Anatomy
How do fossils provide evidence of environmental changes that occurred in the past?
Physical characteristics can tell what the environment that they lived in was like.
What are the different types of divisions of geologic time?
Eons, Eras, Periods, Epochs.
How do the ages of the oldest fossils compare to the age of the Earth?
3.6 BYA (the earth is 4.6 billion years old)
What evidence can scientists use to study Earth’s history?
Rock Strata. We look at the geologic record.
What two methods do scientists use to determine the ages of rocks?
Relative and Absolute dating.
How are geologic principles applied to understanding Earth’s history?
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)
What is a watershed and what are the major watersheds in your state?
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.
What are the components and characteristics of a river system?
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.
Why are wetlands important?
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.
Why are estuaries important?
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.
How can the water quality in a watershed be affected by human activity?
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.
How do scientists study the oceans?
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.
What role do the oceans play in weather and climate?
Convection Currents (Cooling, Rising, Heating, Sinking)
How do we use the ocean as a resource?
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.
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?
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.
What can bioindicators, such as the number and types of macroinvertebrates, reveal about the health of an aquatic ecosystem?
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.
How do scientists classify organisms?
Scientists use common features to place organisms into categories.
What are some common features that scientists use to classify organisms?
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
What is the Linnaean system of classification?
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.
What nonliving substances are important to living organisms?
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.
What is the difference between an ecosystem, a habitat, and a niche?
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)
How do different organisms in a community obtain energy from their environment?
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.
