7th Grade Review

Scientists to Know….• Zacharias Janssen (1590) –put two magnifying

glasses in a tube.

• Anton van Leewenhoek (1600’s) created simple microscope using glass bead for lens.

• Robert Hooke (1665) – looked at cork through microscope and called the “empty boxes” cells.

• Matthias Schleiden (1839) – said all plants are made of plant cells.

• Theodor Schwann (1839) – said all animals are made of animal cells.

• Rudolph Virchow (1856) – said that older cells form new cells

Microscopes

Cells • Cells perform numerous

functions: respiration, waste removal, growth, irritability, and reproduction.

• Cell theory:

a. All organisms are made of cells

b. Cells are the basic unit of life.

c. Cells come from other cells

Onion cells

Cells to Systems……

• Organelles form cells, cells form tissues, tissues form organs, and organs form systems.

• Ex: nervous system; respiratory system; etc……

Cell Review

Differences • Plant cells have chloroplasts that hold

chlorophyll giving them their green color; cell walls, and larger vacuoles to store food.

• Animal cells have centrioles.

Cell Parts and Their Functions…

• Cell membrane – decides what comes in or out.

• Nucleus – directs all activities.• Cytoplasm – gel- like material inside the

cell.• Endoplasmic reticulum - moves things

within the cell (highway system).• Golgi bodies – packages materials to be

moved.• Mitochondria –produces energy.

Organelles Continued….

• Lysosomes –destroy waste

• Ribosomes – make protein

• Chloroplasts - turn light into food

• Cell wall –protects the cell.

• Vacuoles- storage units for food, water, and waste.

Mind Map (can you explain the meaning behind each picture)?

cellmembrane

cell wall

cytoplasm

golgi bodies

lysosomes

vacuoles

ER

ribosomes

mitochondria

nucleus

Cell Tour

Plant Cell

Animal Cell

Cell types• Prokaryotic: simple in structure with no

recognizable organelles.

• Eukaryotic: most plants and all animals. Larger and have developed organelles.

Digestive: breaks down food in to useable molecules

Circulatory: transports nutrients, water, and oxygen throughout body.

Respiratory: brings oxygen to body and releases carbon dioxide.

Excretory: removes waste and excess water.

Cell Processes• Diffusion – moves molecules from where there

are many to where there are few (from high to low concentration).

• Osmosis – the diffusion of water through a cell membrane.

• Cells strive to maintain equilibrium.

Mitosis• Mitosis- the nucleus of a

cell divides and creates two identical daughter cells in a series of phases: prophase, metaphase, anaphase, and telophase.

• Asexual repoduction, single division, occurs in all body cells

Meiosis• Sexual reproduction with two

cellular divisions resulting in four daughter cells with exactly half the number of chromosomes.

• Occurs in organs. • Goes through metaphase,

anaphase, prophase and anaphase.

Terminology to Know…• Unicellular - made up of only

one cell.

• Multi-cellular -made up of many cells.

• Active transport – movement through cell that requires energy

• Passive transport – movement that does not require energy.

• Complex organisms need more cells.

Paramecium

More Vocab• Life cycle – process of being born, growing, aging and dying is called.

• Homeostasis - to maintain internal stability Example: normal body temp.

• Spontaneous Generation -thought that living animals can form without descent from similar organisms. Example: idea that fleas could arise from dust, or that maggots could arise from dead flesh.

Animal/Plant Grouping• Biggest (most complex) to

smallest (least complex) – Kingdom, Phylum, Class, Order, Family, Genus, and Species.

• Species – share common characteristics, can mate, and have fertile offspring.

• Ex: lion and tiger have ligers that are infertile (not a species) but a dog and wolf have pups that are fertile (are a species)

Populations

• Populations (all the same animal) compete for basic resources, mates, and territories.

• Must cooperate with each other to meet needs.

• Have social order to ensure that labor and resources are shared.

• Every organism fills a specific niche (job or role) in its community.

Populations and Niches

Symbiotic Relationships– Mutualism - both organisms benefit.

Ex: clown fish and sea anemone.

– Commensalism - one benefits and the other is unaffected. Ex: flies on a horse

– Parasitism - one benefits and one is harmed. Ex: dog and flea

Clown Fish and Anemone

Living Space

• Ecosystems include forests, the ocean, tidal pool, ponds, etc…• Ecosystems are living communities within a biome.• Biome is defined by climate range (temp and precipitation rates)

and how well the organisms have adapted in that area.• Biomes are made up of ecosystems.

Biomes and Succession

Biomes and Succession

Organisms…• Organisms exist as a member of

their population.

* Organisms adapt to abiotic (non-living) and biotic (living) factors in their home.

Rescuing Animals from Poachers

Vocab to know…

• Phototropism – when plants grow toward their food source. (move toward the sun)

• Hibernation – animal response to cold conditions with a period of lowered metabolism.

• Dormancy –response to adverse conditions with a period of low or suspended metabolism. (trees/plants do this)

Even More• Eutrophication – excess

nutrients in water causing algae blooms.

• Ectotherm: where body heat is regulated to match surroundings. AKA: cold blooded

• Endotherm: regulates body heat within the body. AKA: warm blooded.

Genetics• DNA is a double helix molecule.• It includes four components that

form a chemical code.• Chromosomes are strands of DNA.• Genes are sections of chromosomes

that carry the code for a specific trait.

• The basic laws of Mendelian genetics explains the transmission of some traits that can be inherited from generation to generation.

DNA and Criminal Investigation

More on Genetics…• Genetic engineering is when the

genetic code is manipulated by man to get a desired product .

• There are practical applications in medicine, agriculture, and biology.

• Evolutionary processes include mutations, adaptations, natural selection, and extinction.

Ex. UsingMiracleGrow…

Evolutionary Processes• Adaptation – a change that increases chance of

survival.• Mutation – a change that does not help the organism

to survive. (sometimes harmful)• The evidence for evolution is from the fossil record,

radioactive dating, genetic information, distribution of animals, and similarities within species.

• Heterozygous gene (hybrid) – the genes in the genotype are different. Ex. (Bb)

* Homozygous gene (purebred) – the genes in the genotype are the same. Ex. (bb, BB)

Genetics

All organisms need food, water, air, shelter, energy, and space to survive.

A food chain shows relationships between living organisms.

A food web is two/more food chains hooked together.

A pyramid shows relative amounts of energy available at each level.

Decomposers – organisms that break down other organisms. Ex. Bacteria.

Producers (autotroph) bottom of any web, chain, or pyramid and make their own food.

Consumers (heterotrophs) –eat other living things.

1st level consumer– herbivores (eat plants and algae)

2nd level consumer –carnivores, eat the herbivores.

3rd level consumer – they are at the top of the food chain.

Life Processes• All organisms need food, water, air,

shelter, energy, and space to survive.

• A food chain shows relationships between living organisms.

• A food web is two/more food chains hooked together.

• A pyramid shows relative amounts of energy available at each level.

• Decomposers – organisms that break down other organisms. Ex. Bacteria.

More on life…• Producers (autotroph) bottom

of any web, chain, or pyramid and make their own food.

• Consumers (heterotrophs) –eat other living things.

• 1st level consumer– herbivores (eat plants and algae)

• 2nd level consumer –carnivores, eat the herbivores.

• 3rd level consumer – they are at the top of the food chain.

Vertical Farms…the future?

Photosynthesis Cycle

Ammonia is given off by dead plants and animals.

Predators kill and eat other animals.

Prey are the hunted. Omnivores eat animals

and plants. Herbivores eat only

plants. Carnivores eat only

animals. Scavengers feed off of

dead animals.

Nocturnal animals are awake during the night and sleep during the day.

Diurnal animals are awake during the day and sleep during the night.

Nocturnal Animals

Finishing it all up…• Extinction is when a species dies

out.• Natural Selection – “only the

strong survive”…is when nature decides who lives and who dies.

• Biodiversity – means many different forms of living creatures in one area.

• Ex. The ocean and the rain forest are extremely biodiverse.

Just for fun!