7th Grade End of the Year Final Review

Cells

Cell theory:

  1. All living things are made of cells.
  2. Cells are the basic unit of structure & function in living things.
  3. All cells come from pre-existing cells.

Cell organelles:

  • Nucleus-control center of the cell
  • Chloroplasts-traps energy from sunlight and uses it to make food
  • Cell wall-gives plant cells their rigid, boxlike shape; support & protect
  • Cell membrane-controls movement of materials in & out of cell
  • Cytoplasm-jelly-like substance that supports & protects cell organelles
  • Mitochondrion-breaks down sugar (glucose) to produce energy; “powerhouse”
  • Vacuole-stores food, water & wastes

Know the differences between plant & animal cells. Plants cells have a cell wall & chloroplasts but animal cells do not. Animal cells have lysosomes which are rarely found in plant cells.

Organic Compounds

All organic compounds contain carbon and other elements such as hydrogen, nitrogen, oxygen, phosphorus, or sulfur. CHNOPS

Chromosome Theory of Inheritance

The chromosome theory of inheritance says that genes are carried from parents to offspring on chromosomes.

Sexual & Asexual Reproduction

Sexual reproduction-involves 2 parents (egg & sperm) & produces genetically diverse offspring (has a better chance of surviving changes in the environment)

Asexual reproduction-involves 1 parent & produces genetically identical offspring (ex. budding, fragmentation, cell division, self pollination)

Body Systems

Know the main functions of each body system and how they work together.

Circulatory system-transports oxygen, nutrients & wastes

Respiratory system-brings in oxygen, removes carbon dioxide

Nervous system-carries messages back & forth between the brain & other parts of the body

Muscular system

Skeletal system

Digestive system

Excretory system

Reproductive system

Integumentary system

Endocrine system

Chemical & Mechanical Digestion

Mechanical digestion-the physical breaking apart of food; a physical change (ex. chewing, churning of stomach)

Chemical digestion-when food is broken down into a new substance; causes a chemical change (ex. enzymes, digestive juices)

Biodiversity

Biodiversity refers to the number of different species in an ecosystem.

Biodiversity contributes to the sustainability of an ecosystem. With less biodiverisity, the extinction of a species greatly affects an ecosystem.

An ecological benefit to biodiversity is that the ecosystem remains more stable.

Natural Selection

Darwin observed that the beaks of finches in the Galapagos Islands were adaptations related to the foods the finches ate.

Natural selection is the process by which individuals that are better adapted to their environment are more likely to survive and reproduce.

Selective breeding is when humans bred animals or plants to get desired characteristics.

Succession

Primary succession steps- no soil or life-- lichens & mosses grow--soil forms--weeds & grasses grow--trees & shrubs grow

Secondary succession is the series of changes that occur when an ecosystem has been disturbed but soil and organisms still exist.

Ecosystems

An autotroph is an organism that can make its own food.

A producer is an organism that can make its own food.

An omnivore is a consumer that eats both plants and animals.

1st level consumers eat only producers.

Be able to understand food webs and energy pyramids.

Dichotomous Keys

Be able to read and follow a dichotomous key.

Groundwater & Surface Water

Pollution that gets into groundwater is difficult to remove and can travel far distances from the point of pollution.

Causes of surface water pollution:

Chemical wastes, metal wastes, animal wastes, pesticides, fertilizer, sediments, heat, oil & gasoline

Causes of groundwater pollution:

Chemical wastes, metal wastes, human wastes, water wastes, pesticides, fertilizer, oil & gasoline

Work

In science, in order for work to be done on an object, the force exerted must be in the same direction as the object’s motion.

Be able to identify examples of work being done.