Physical Changes
changes in the state or appearance of matter that do not alter the chemical composition
Physical Changes
Characteristics:
Reversible
No new substances formed
Melting, Freezing, Evaporation, Condensation, Sublimation
Examples of Physical Changes
Chemical Changes
changes result in the formation of new substances with different properties from the original substances.
Combustion
Burning of wood or gasoline, producing CO₂ and water.
Chemical Changes
Characteristics:
Usually irreversible
Formation of new substances
Energy changes (exothermic or endothermic reactions)
Succession
The process by which the structure of a biological community evolves over time.
Primary Succession
Occurs in lifeless areas where there is no soil (e.g., after a volcanic eruption)
Secondary Succession
Occurs in areas where a community has been disturbed but soil remains (e.g., after a forest fire).
Deforestation
Clearing of forests for agriculture or urban development.
Pollution
Release of harmful substances into the environment.
Climate Change
Long-term changes in temperature and weather patterns due to human activities such as burning fossil fuels.
Urbanization
Expansion of cities leading to habitat loss and fragmentation.
Agricultural Practices
Use of pesticides and fertilizers.
Mutations
Changes in the DNA sequence of an organism
Point Mutations
Changes in a single nucleotide (e.g., substitution, insertion, deletion).
Mutations, Genetic Variation
Genetic Changes
Chromosomal Mutations
Changes in the structure or number of chromosomes (e.g., duplications, deletions, inversions, translocations).
Genetic Variation
Differences in DNA sequences among individuals within a population.
Natural Selection
Speciation
Evolutionary Changes
Natural Selection
The process by which organisms with favorable traits are more likely to survive and reproduce, passing those traits to the next generation
Speciation
The formation of new and distinct species in the course of evolution
Allopatric Speciation, Sympatric Speciation
Speciation types
Sympatric Speciation
Occurs without geographic separation, often through genetic or behavioral differences.
Example: Certain plants can undergo polyploidy, where the number of chromosomes doubles, leading to reproductive isolation from the parent population.
Allopatric Speciation
Occurs when populations are geographically separated.
Geographic isolation
Genetic drift
Natural selection
Mutation
Sexual selection
Factors Influencing Speciation
Concentration, Temperature, Catalysts,
Factors Affecting Rates
Surface Area
Greater surface area increases the rate by allowing more particles to collide
Reversible Reactions and Equilibrium
Reactions that can proceed in both forward and reverse directions.
Impact of Humans on the Carbon Cycle
Combustion of Fossil Fuels
Deforestation
Agricultural Practices
Carbon Sequestration
Carbon Cycle
Movement of carbon between the atmosphere, hydrosphere, biosphere, and geosphere
Nitrogen Cycle
Movement of nitrogen between the atmosphere, soil, and living organisms
Carbon Cycle, Nitrogen Cycle, Water Cycle, Phosphorus Cycle
What are the Biogeochemical Cycles