Mrs. McCarthy’s MCAS Review Life Science

6 th Grade Curriculum –Classification of Organisms –Structure and Function of Cells –Systems in Living Things –Reproduction & Heredity –Evolution & Biodiversity –Living Things & Their Environment –Energy & Living Things –Changes in Ecosystems Over Time

Structure and Function of Cells Cells are the basic units of life. All living things are made of cells. Cells are very small and can only be seen with a microscope.

Cells There are different types of cells: –Animal Cells –Plant Cells Some living things are multi-cellular –Example: plant, animal Some living things are unicellular –Example: bacteria, yeast

Parts of the Cell Cell Wall-the outside of the cell that strengthens the cell membrane Cell Membrane- keeps cytoplasm in; allows nutrients in & waste out Chloroplasts-hold green chlorophyll for photosynthesis Vacuoles- store water & fluid Nucleus- holds cell’s DNA Cytoplasm-fluid in cell Mitochondria- breakdown food in the cell

Plant Cell Plant Cells are found in plants. Unlike Animal Cells, Plants Cells contain: Cell Wall & Chloroplasts so that they can make food using photosynthesis.

Animal Cell Animal Cells are found in animals. Unlike Plants Cells, Animal Cells do not contain: Cell Wall & Chloroplasts.

Cellular Functions Cells function similar to living organisms: –Extracting Energy from Food –Disposing of Waste –Reproduction (Mitosis)

Heredity All living things have traits. Traits are stored in chromosomes. These are passed on from one generation to the next in genes. Human cells contain about 30,000 different genes on 23 different chromosomes. Punnett Squares show possible inheritance.

Reproduction There are 2 types of reproduction: –Sexual: 2 Parent Cells Join Together to Form a New Individual; Offspring Inherit Half of Their Genes from each Parent Example: Plants & Animals –Asexual: only 1 Parent Cell is Needed; Parent Cell is Copied; Mitosis Occurs Example: Single-celled Organisms

Genes of DNA Cells & Body Tissues Organs Systems

Systems in Living Things The Human Body’s Major Systems: –Digestion: Food Energy –Respiration: Breathing –Reproduction: Population –Circulation: Blood Flow –Excretion: Waste –Immune: Protection from Disease –Movement, Control, Coordination: Moving, Thinking, Planning, Processing

Classification of Organisms Classification is the arrangement of organisms into orderly groups based on their similarities. Levels: Kingdom- large general group Phylum- Classes- Orders- Families- Genus- Species- one kind Kingdom’s are continuously broken down into classified groups until species King----Kingdom Philip---Phylum Came--Classes Over----Orders For------Families Grape--Genus Soda---Species Hint:

Kingdoms All living organisms belong to one of the kingdoms There are five Kingdoms: 1.Bacteria- E. coli, 2.Protista- single-celled organisms 3.Plantae- plants, flowers & trees 4.Fungi- fungus, mold & mushrooms 5.Animalia- animals, people, pets, bugs Fungi Plantae Protista Animalia Bacteria

Evolution & Biodiversity Evolution: organisms adapt and change over time Evidence: geology, fossils, comparative anatomy Extinctions: many species have not been able to adapt to habitat changes over time Survival of the fittest

Living Things & Their Environment Organisms interact with one another and have different functions within an ecosystem that enable the ecosystem to survive. Circle of Life

Food Web- Energy from food flows from one organism to another Parts of the Food Web: –Producers- use sunlight to make food Example: Plants –Consumers-eat producers & organisms Example: animals –Decomposers-break down remains of dead organisms Example: bacteria & fungi

Decomposers & Nitrogen Cycle Decomposers- Living organisms break down dead plants & animals (bacteria, fungus) Nitrogen is produced in this cycle. Broken down material is used for compost and has nutrients in it that contribute to the system.

Plants use energy from sunlight to make sugars from carbon dioxide and water through photosynthesis. This food can be used immediately, stored for later use, or used by other organisms.

Photosynthesis The process where plants capture light energy from the sun and change it into food.

Ecosystems Ecosystem- the habitat of living organisms Land: Forests, Grasslands, Deserts, Tundra Marine: Beaches, Seafloor, Reefs Freshwater: Moving Water, Still Water, Wetlands

Changes in Ecosystems Over Time Changes in the ecosystem can cause extinction, habitat damage, & global warming. Ecosystems are effected by: –Pollution –Resource Depletion –Alien Species –Human Population Growth –Habitat Destruction

Energy Resources Energy Resources: Natural, Fossil Fuels, & Alternatives Natural Resources include wood, gasoline, wind Fossil Fuels: nonrenewable energy resource - Made over millions of years from buried organisms - Create environmental pollution problems - Examples: coal, natural gas, petroleum Alternatives: renewable & easy to replace resources - Most are cleaner & safer. - Examples: Solar, Wind, Hydroelectric, Biomass, Nuclear (Dangerous)