Overview
This lecture covers Unit A and part of Unit B from "Science in Action 9," outlining the foundations of biological diversity and introducing properties and classification of matter in chemistry.
Unit A: Biological Diversity
Definition and Importance
- Biological diversity is the variety of species and ecosystems on Earth, including genetic diversity within species.
- Ecosystem, community, and genetic diversity are key components.
- High diversity increases species' survival against environmental changes.
Diversity in Ecosystems
- Ecosystems are systems where living (biotic) and non-living (abiotic) elements interact.
- Populations are groups of the same species in an area; communities consist of different species living together.
Species Variation
- Genetic diversity means variations among individuals within a species.
- Variation enables survival during environmental changes (e.g., disease resistance, adaptation).
Classification of Life
- Carolus Linnaeus created a system using Latin names for genus and species.
- Organisms are classified into kingdoms, phyla, class, order, family, genus, and species.
Interdependence and Niches
- Species rely on each other for food, shelter, and reproduction.
- Types of symbiosis: mutualism (both benefit), commensalism (one benefits, one unaffected), parasitism (one benefits, one harmed).
- A niche describes the role an organism plays in its ecosystem.
Natural Selection and Survival
- Natural selection is when environmental factors determine which individuals survive and reproduce.
- Variability is important for adaptation and species continuity.
Reproduction and Inheritance
- Asexual reproduction (one parent) yields identical offspring; sexual reproduction (two parents) results in genetic variation.
- Heritable traits are passed down; non-heritable traits are acquired (e.g., learning to play an instrument).
DNA, Genes, and Chromosomes
- DNA holds the genetic code; genes are DNA segments coding for traits.
- Chromosomes are DNA packages in the nucleus.
- Mitosis (asexual) keeps chromosome number constant; meiosis (sexual) halves it for gametes.
Human Impact and Conservation
- Human activities (habitat destruction, pollution) reduce biodiversity.
- Conservation strategies include protected areas, restoration, seed banks, and captive breeding.
Unit B: Matter and Chemical Change (Introduction)
Lab Safety and WHMIS
- Safety procedures, PPE, and understanding WHMIS hazard symbols are essential in lab work.
Properties and Classification of Matter
- Matter exists in three states: solid, liquid, gas.
- Physical properties: color, melting/boiling point, hardness, density, solubility, conductivity.
- Chemical properties describe how substances react (e.g., ability to burn, reaction with acids).
Mixtures and Pure Substances
- Pure substances: elements and compounds.
- Mixtures: mechanical mixtures (heterogeneous), solutions (homogeneous), suspensions, colloids.
Changes in Matter
- Physical changes alter state or appearance without changing composition (melting ice).
- Chemical changes create new substances (rusting, burning).
Key Terms & Definitions
- Biodiversity — Variety of life forms within a given ecosystem, region, or on Earth.
- Ecosystem — Community of interacting organisms and their environment.
- Population — Group of individuals of the same species in a specific area.
- Gene — DNA segment coding for a specific trait.
- Niche — Role and position a species has in its environment.
- Symbiosis — Close association between two different organisms.
- Natural selection — Process where organisms better adapted to their environment survive and reproduce.
- Asexual/Sexual Reproduction — Asexual: offspring identical to parent; sexual: offspring genetically varied.
- Physical Property — Observable characteristic without changing substance composition.
- Chemical Property — How a substance reacts with others to form new substances.
- Mixture — Combination of two or more substances not chemically combined.
Action Items / Next Steps
- Review your notes on biodiversity, inheritance, and properties of matter.
- Complete practice activities/labs on classifying matter and graphing diversity data.
- Prepare for upcoming discussions and assignments on conservation methods and lab safety.
- Read next sections on atomic theory and chemical reactions.