Vestigial structures are remnants of ancestral traits that have lost their original function.
Speciation is the process by which new species arise from existing ones due to isolation and genetic divergence.
Adaptive radiation is the diversification of a single ancestral species into a variety of ecological niches.
Biotic factors are living components of an ecosystem, while abiotic factors are non-living components.
The biosphere is the part of Earth that supports life, including all living organisms and their environments.
Ecology is the study of interactions between organisms and their environments.
The ecosystem includes all living organisms and their physical and chemical environments.
A community is a group of different species that live and interact in the same area.
A population is a group of individuals of the same species living in the same area.
Biodiversity refers to the variety of life forms in an ecosystem, including species diversity, genetic diversity, and ecosystem diversity.
Keystone species have a disproportionate impact on their environment and play a critical role in maintaining ecosystem stability.
Trophic levels represent different feeding levels in an ecosystem, including producers, consumers, and decomposers.
The energy pyramid represents the flow of energy through trophic levels, with energy decreasing at each level.
The water cycle involves the movement of water through various reservoirs, including oceans, atmosphere, and land.
The carbon cycle involves the movement of carbon dioxide through photosynthesis, respiration, decomposition, and combustion.
The nitrogen cycle involves the conversion of nitrogen gas into forms that can be used by plants and animals through processes like nitrogen fixation and denitrification.
The greenhouse effect is the natural process that warms the Earth’s surface by trapping heat in the atmosphere.
Human activities, such as burning fossil fuels, contribute to an enhanced greenhouse effect, leading to global warming and climate change.
Biotic factors in an ecosystem include living organisms such as plants, animals, fungi, and microorganisms.
Abiotic factors in an ecosystem include non-living components such as temperature, sunlight, water, soil, and air.
Primary succession occurs in areas where no soil is present, such as after a volcanic eruption or glacial retreat.
Secondary succession occurs in areas where soil is already present, such as after a forest fire or abandoned agricultural land.
The law of conservation of energy states that energy cannot be created or destroyed, only transferred or transformed.
The first law of thermodynamics, also known as the law of conservation of energy, states that the total energy of an isolated system remains constant.
The second law of thermodynamics states that energy spontaneously tends to disperse, leading to an increase in entropy.
Entropy is a measure of the disorder or randomness in a system.
The universe tends toward higher entropy and greater disorder over time.
Heat is the transfer of thermal energy from a higher temperature object to a lower temperature object.
Work is done when a force is applied to an object and the object moves in the direction of the force.
The SI unit of energy is the joule, and the SI unit of power is the watt.
Temperature is a measure of the average kinetic energy of the particles in a substance.
Absolute zero is the lowest possible temperature, at which all molecular motion ceases.
Conduction is the transfer of heat through direct contact between particles of a substance.
Convection is the transfer of heat through the movement of fluid (liquid or gas) particles.
Radiation is the transfer of heat through electromagnetic waves, such as infrared radiation.
Heat engines convert thermal energy into mechanical work.
The efficiency of a heat engine is the ratio of the work output to the heat input, expressed as a percentage.
The Carnot efficiency is the maximum possible efficiency of a heat engine operating between two temperature reservoirs.
The coefficient of linear expansion measures how much a material’s length changes with temperature.
The coefficient of volume expansion measures how much a material’s volume changes with temperature.
Sound waves are mechanical waves that require a medium for propagation.
The frequency of a sound wave is the number of vibrations per unit time and is measured in hertz (Hz).
The wavelength of a sound wave is the distance between two consecutive compressions or rarefactions.
The speed of sound in a medium depends on the properties of the medium, such as its density and elasticity.
The Doppler effect causes a shift in the frequency of a sound wave when the source of the wave is moving relative to an observer.
The Doppler effect is responsible for the change in pitch of sound from a moving source, such as a siren on a moving vehicle.
The pitch of a sound is related to the frequency of the sound wave, with higher frequencies corresponding to higher pitches.
Resonance occurs when an external force matches the natural frequency of an object, leading to increased amplitude of vibrations.
Resonance is used in musical instruments, such as string instruments and wind instruments, to amplify sound.
Ultrasound waves have frequencies higher than the upper limit of human hearing and are used in medical imaging and industrial applications.
Echoes are reflections of sound waves from surfaces that are far enough away to cause a noticeable time delay.
Sonar (sound navigation and ranging) uses sound waves to determine the depth of water and locate objects underwater.
The primary colors of light are red, green, and blue.
Red light has the longest wavelength in the visible spectrum.
White light is a combination of all colors in the visible spectrum.
A concave mirror can produce both real and virtual images, depending on the object’s position.
The primary colors of pigment are cyan, magenta, and yellow.
The colors cyan, magenta, and yellow are subtractive primaries used in color mixing for printing.
The phenomenon of interference can result in the formation of bright and dark fringes.
The colors seen in a thin film interference pattern are due to the difference in the path length traveled by light waves.
The photoelectric effect demonstrates that light can behave as both particles and waves.
The maximum number of electrons in an energy level can be calculated using the formula 2n², where n is the principal quantum level.
The electron configuration of an atom describes the arrangement of its electrons in different energy levels and subshells.
The Pauli exclusion principle states that no two electrons in an atom can have the same set of quantum numbers and must have opposite spins.
The Aufbau principle states that electrons fill atomic orbitals in order of increasing energy.
The valence electrons of an atom are involved in its chemical reactions and bonding.
An exothermic reaction releases energy to its surroundings.
The activation energy of a chemical reaction is the minimum energy required for the reaction to occur.
A catalyst increases the rate of a chemical reaction by lowering the activation energy.
In an exothermic reaction, the products have lower potential energy than the reactants.
An endothermic reaction absorbs heat from its surroundings.
Chemical equilibrium is reached when the rates of the forward and reverse reactions are equal.
Le Chatelier’s principle states that if a system at equilibrium is subjected to a change, it will adjust itself to counteract the change and establish a new equilibrium.
An acid donates protons (H⁺ ions), and a base accepts them.
The pH scale measures the acidity or basicity of a solution.
A pH of 7 is considered neutral, while values below 7 are acidic and values above 7 are basic.
Buffers are solutions that can resist changes in pH when an acid or base is added.
Organic chemistry is the study of compounds containing carbon and hydrogen.
The simplest organic compounds are hydrocarbons, which consist of only carbon and hydrogen.
Isotopes of an element have the same number of protons but a different number of neutrons.
The atomic number of an element is equal to the number of protons in its nucleus.
The mass number of an element is the sum of its protons and neutrons.
The periodic table is organized based on the increasing atomic number of elements.
Elements in the same group or column of the periodic table have similar chemical properties.
The alkali metals are located in Group 1 of the periodic table and are highly reactive.
Halogens are located in Group 17 of the periodic table and are known for their high reactivity with metals.
Noble gases are located in Group 18 of the periodic table and are generally inert due to their stable electron configurations.
The modern periodic table was developed by Henry Moseley and is based on the atomic number of elements.
Covalent bonds involve the sharing of electrons between atoms.
Ionic bonds result from the transfer of electrons from one atom to another.
An atom with a positive or negative charge is called an ion.
The chemical formula of a compound indicates the types and ratio of atoms present in the compound.
The molecular formula gives the actual number of atoms of each element in a molecule.
Isomers are compounds with the same molecular formula but different structural arrangements.
A hydrocarbon with a single bond is called an alkane.
A hydrocarbon with one or more double bonds is called an alkene.
A hydrocarbon with one or more triple bonds is called an alkyne.
Structural isomers have the same molecular formula but different structural arrangements.
Optical isomers (enantiomers) are mirror-image stereoisomers that rotate plane-polarized light in opposite directions.
A saturated hydrocarbon contains only single bonds and has the maximum number of hydrogen atoms.
