Science Practice Flashcards
Ecosystems: Fundamental Concepts and Components
Abiotic Factors: Defined as any non-living part of an ecosystem. These factors provide the environmental context in which organisms live.
Examples include: Air, Water, Sunlight, Rocks, and Temperature.
Biotic Factors: Any living or once-living organisms within an ecosystem. This includes all biological life forms and their remains.
Examples include: Mushrooms, trees, plants, fungi, and animals.
Ecological Succession
Definition: A series of predictable changes that occur in a community over time.
Types of Succession:
Primary Succession:
Timeline: A series of community changes occurring over a very long period of time (thousands of years).
Condition: Occurs where a new ecosystem is formed in an area where nothing previously existed.
Starting State: There is no soil, plants, or animals present at the start.
Examples: Volcanic eruptions forming new land; glaciers stripping an area down to bedrock; the formation of new sand dunes.
Secondary Succession:
Timeline: A series of community changes occurring over a relatively shorter period of time (hundreds of years).
Condition: The formation and regrowth of an ecosystem following a disturbance.
Examples: Regrowth after a flood, a forest fire, or other natural disasters.
Levels of Ecological Organization
Ecological organization is structured from the smallest unit to the largest global system:
Organism: Any single living thing. A key characteristic is that it can only breed with members of the same species. This is the smallest level of organization. Examples include a single animal, plant, or bacteria.
Population: A group of organisms of the same species living in a specific area. While they are the same species, individuals can have different genetic makeups (e.g., differences in eye color or hair color). Examples: All lions in a grassland; all humans in New York City.
Community: All of the populations across different species living in an area at a given time. Example: All zebras, elephants, and giraffes in a grassland.
Ecosystem: Consists of all the living (biotic) and non-living (abiotic) factors in an area interacting together. Ecosystems can vary in size from large to small. Example: A pond ecosystem.
Biome: A set of ecosystems that share similar characteristics, climate, plant life, and animal life. Organisms within a biome have specific adaptations for that environment. Examples: Tundra, rainforest, desert.
Biosphere: The sum of all ecosystems on Earth. This is the largest level of ecological organization and includes all biomes and everything within them.
Organism Relationships and Roles
Producers (Autotrophs): Organisms that obtain energy from the Sun through the process of photosynthesis. Examples: Bushes, trees, and grass. They are eaten by herbivores and omnivores.
Consumers (Heterotrophs): Organisms that obtain energy by eating other organisms. Consumers are classified into three types:
Herbivores: Eat only plants.
Carnivores: Eat only meat.
Omnivores: Eat both plants and meat.
Examples: Deer, sharks, bears.
Decomposers: Organisms that obtain energy by breaking down dead or decaying organisms. Their vital role is to recycle nutrients back into the soil to be used again by plants and other producers. Examples: Worms, bacteria, insects, fungi.
Predators: Animals that hunt, kill, and consume other animals to meet their energy needs. Their survival is directly dependent on the populations and health of their prey. Examples: Lions, seals, frogs.
Prey: Animals that are hunted, killed, and eaten for the energy needs of predators. A single prey species can have many different types of predators. Examples: Rats, worms, rabbits.
Parasite: An organism that lives in or on another organism (the host) and causes harm to it. This can cause minor irritations, illness, and sometimes death. Examples: Fleas, ticks, lice.
Host: The organism that a parasite lives in or on. The parasite consumes nutrients and blood from the host's body. Examples: Dogs, humans, cows.
Symbiotic Relationships
Symbiosis: A specific relationship between two different organisms.
Mutualism: A relationship where both organisms benefit. Examples: Bees and flowers; oxpeckers and zebras.
Commensalism: A relationship where one of the two organisms benefits, while the other experiences no effect (neither helped nor harmed). Examples: Sharks and remoras; tree frogs and plants.
Parasitism: A relationship where one organism benefits while the other is harmed. Examples: Fleas and dogs; aphids and plants.
Adaptations for Survival
Definition: Traits that help an organism survive and reproduce in its specific environment or biome. Example: Camouflage allows animals to hide from predators.
Types of Adaptations:
Structural/Physical: Physical traits that allow an organism to blend in with its surroundings, such as camouflage.
Behavioral: Specific behaviors that help an organism survive, such as birds migrating to warmer climates during the winter season.
Physiological: Internal functions that assist survival. Example: The production of venom. (Note: These may not be on the exam).
Particle Theory of Matter
The Six Principles of Particle Theory:
All matter is made of tiny particles.
Particles are always moving.
Particles attract each other.
Temperature represents the average kinetic energy of the particles and directly affects particle movement.
Different substances are composed of different types of particles.
The spaces between particles change depending on the state of matter.
States of Matter
Solid:
Shape: Fixed.
Volume: Fixed.
Particle Movement: Particles vibrate in place.
Example: A pen.
Liquid:
Shape: Changes to fit container.
Volume: Fixed.
Particle Movement: Particles slide past each other.
Example: Water.
Gas:
Shape: Changes.
Volume: Changes.
Particle Movement: Particles move freely.
Example: Air.
Substances and Mixtures
Pure Substance: Contains only one type of particle.
Mixture: Contains two or more substances combined.
Homogeneous Mixtures: Look the same throughout (uniform). Example: Salt water ().
Heterogeneous Mixtures: Different parts can be seen (non-uniform). Example: Salad ().
Physical and Chemical Changes
Physical Change: No new substance is formed; the substance may just break apart or change state. Example: Melting ice.
Chemical Change: A new substance is formed because the internal chemical composition is changed. Example: Rusting iron.
Signs of Chemical Change: Color change, gas production, heat or light released, or the formation of a precipitate.
Heat and Temperature
Heat: The energy transferred between objects.
Temperature: The measure of the average kinetic energy of the particles in a substance.
Methods of Heat Transfer:
Conduction: Heat transfer through direct physical contact. Example: A metal spoon in hot soup.
Convection: Heat transfer through moving fluids (liquids or gases). Example: Boiling water.
Radiation: Heat transfer through electromagnetic waves. Example: The Sun warming the Earth.
Earth's Crust and Continental Drift
Alfred Wegener's Theory of Continental Drift: Proposed that the continents were once joined together in a single supercontinent called Pangaea.
Evidence for Continental Drift:
Matching coastlines of different continents.
Similar fossils found on widely separated continents.
Matching rock layers across oceans.
Ancient climate evidence (e.g., tropical fossils in cold regions).
Layers of the Earth:
Crust: The thin, solid outer layer.
Mantle: The thickest layer, composed of semi-solid rock.
Outer Core: A liquid layer made of iron and nickel.
Inner Core: A solid layer made of iron and nickel; it is the hottest layer of the Earth.
Minerals: Naturally occurring, inorganic solids. They are identified using several tests:
Color.
Streak.
Luster.
Cleavage.
Hardness.
Forces and Structures
Classifying Structures:
Natural: Created by nature. Example: Trees.
Man-Made: Built by humans. Example: Buildings.
Structural Types:
Solid Structures: Advantages include being very strong and stable. Disadvantages include being heavy and requiring a large amount of material. Examples: Dams, Pyramids.
Frame Structures: Advantages include being lightweight. Disadvantages include a risk of weakening if certain parts fail. Examples: Bridges, towers.
Shell Structures: Advantages include a strong outer covering. Disadvantages include the potential to crack easily. Examples: Helmets, eggs.
Form vs. Function:
Form: Relates to the appearance or shape of a structure.
Function: Relates to the job or purpose the structure serves.
The Six Types of Forces
Tension: A pulling force. Example: Pulling on both ends of a stick.
Compression: A pushing force. Example: Sitting down on a chair.
Torsion: A twisting force. Example: Wringing out a wet towel.
Shear: A sliding force. Example: Scissors cutting through a material.
Bending: A force that causes curvature. Example: Bending a stick.
Gravity: A force that pulls objects toward the Earth.
Mass vs. Weight
Mass: The total amount of matter in an object. It is measured in kilograms ().
Weight: The force of gravity acting on an object. It is measured in Newtons ().
Center of Gravity and Loads
Center of Gravity: The specific point where the weight of an object is evenly balanced. It can be changed by adding weights to one side. It can be located by balancing an object on your fingers.
Load Types:
Dead Load: The permanent weight of the structure itself. Examples: Structural elements like beams and columns.
Live Load: Moving or changing weight. Example: Cars traveling on a bridge.
Environmental Load: Forces related to weather. Examples: Wind, snow, and rain. These are categorized as live loads because they are constantly changing.
Bridge Engineering
Beam Bridge: Simple and inexpensive to construct. However, it has a limited span length.
Arch Bridge: Very strong under compression. Requires a solid foundation at the ground to support the arch.
Truss Bridge: Extremely strong build capable of withstanding significant weight. However, it is complex, time-consuming to build, and vulnerable to corrosion.
Suspension Bridge: Capable of the longest spans of all bridge types. However, it is very expensive to build.
Structural Failure and Obsolescence
Structural Failure: Occurs when a structure can no longer support its required loads. Causes include:
Poor design.
Material fatigue.
Overloading.
Obsolescence: When a structure or product is no longer useful even if it still functions properly.
Planned Obsolescence: When a product is intentionally designed with a limited lifespan so consumers must eventually replace it. Example: Apple allegedly making iPhone batteries weaker over time.
Perceived Obsolescence: When a consumer is persuaded that a product is no longer usable or is outdated even though it works perfectly. Example: Buying new clothes solely to follow current fashion trends.