Seventh Grade Review Life Science
Living organisms require food, water, shelter, energy, and space to survive
Cells are the smallest units that carry out activities of life
The three components of the cell theory are: 1) all organisms are made up of one of more cells 2) cells are the basic unit of structure and functions in all organisms 3) all cells come from cells that already exist
Zacharias Janssen, in 1590, was the first to put two magnifying glasses together in a tube
Anton van Leeuwenhoek, in the mid 1600 s, created a simple microscope, and with a tiny glass bead for a lens
Robert Hooke, in 1665, looked at slices of cork under his microscope, and called the empty boxes he saw cells
In 1839, Matthias Schleiden, studied plants and concluded that all plants were made of cells
In 1839, Theodor Schwann, studied animals and concluded that all animals were made of cells
Rudolph Virchow, in 1856, hypothesized that older cells divide to form new cells
Cells perform numerous functions and processes including respiration, waste removal, growth, irritability, and reproduction
Cells that have the same goal group together to form tissues, tissues that have the same goal group together to form organs, organs with similar goals group to work in organ systems
The differences between plant cells and animal cells are: plant cells have chloroplasts, cell walls, and larger vacuoles. Animal cells have centrioles during mitosis
The cell membrane forms the outer boundary of the cell and only allows certain things to enter and exit Cytoplasm is the gel-like material inside the cell The cell wall is located outside of the cell membrane and is used to support and protect the cell found in plants, monerans, and fungi.
The nucleus directs all of the activities of the cell and contains all of the genetic blueprints for the operations of the cell
The endoplasmic reticulum acts as the highway system of the cell and moves materials around the cell, Golgi bodies of the cell packages materials to be moved to the outside of the cell
The mitochondria of a cell are the powerhouse of the cell that breaks down food molecules and produces energy for the cell
Lysosomes of a cell digest and destroy waste products and worn-out cell parts. Vacuoles are temporary storage units for the cells that may contain food, water, or waste
Ribosomes make proteins for the cell
Chloroplasts are organelles in plant cells that transform light energy into chemical energy in the form of sugar C6H12O6 glucose
Cells strive to maintain equilibrium Diffusion is the movement of molecules from where there are many to where there are few (high to low concentration). Osmosis is the diffusion of water through a cell membrane
Cell Reproduction Mitosis is the process in which the nucleus of a cell divides and replicates to form two identical nuclei in a series phases: prophase, metaphase, anaphase, and telophase Meiosis is the process of division in cells that produces sex cells
Unicellular organisms are made of only one cell
Multi-cellular organisms are made of many cells
Multi-cellular organisms are complex in that there is a division of labor for carrying out the necessary life processes
The life needs of plants are light, energy source, gases, water, and nutrients
Producers make their own food by photosynthesis and are the beginning Chlorophyll is a chemical in chloroplasts that can absorb or trap energy and transform it into chemical energy called glucose of food chains
Binomial nomenclature is the system used for classifying organisms Kingdoms are arranged using system of names recognizable around the world
The Three Domain Eukaryote All these organisms have a nucleus in their cells Bacteria prokaryotes (no nucleus) modern bacteria Archaea prokaryotes (no nucleus) anceint bacteria that live in extreme conditions
The Six Kingdoms Fungi (Eukaryote) Animals (Eukaryote) Plants (Eukaryote) Protists (Eukaryote) Eubacteria (Bacteria) Arcaebacteria (Archaea)
Eubacteria Kingdom Unicellular, prokaryotic cells No nucleus All have a cell wall Cassified into two groups, autotrophs, and heterotrophs.
Archaebacteria Prokaryotes Very ancient Live in extreme conditions Autotrophs and heterotrophs
Protista Kingdom Unicellular or multicellular, eukaryotic nucleus membrane form colonies or chains absorbs, ingests or photosynthesize food
Fungi Kingdom Multi-cellular eukaryotic organisms Parasitic or saprophytic Reproduce using spores
Plants Kingdom Multi-cellular eukaryotes Producers, cells contain chlorophyll Divided into nonvascular and vascular
Animal Kingdom Divided into nonvertebrates and vertebrates Eukaryotic cells
Populations Populations interact by competing for basic resources, mates, and territory Populations cooperate with each other to meet needs Populations have social order to ensure that labor and resources are shared.
Every organism fills a specific niche, or role in its community
Independent behavior and group behavior can influence a population.
Symbiotic relationships include mutualism, commensalism, and parasitism Mutualism occurs when both organisms benefit Commensalism occurs when one organism benefits and the other is unaffected. Parasitism occurs when one organism benefits and the other is harmed
Ecosystems Examples of some ecosystems are forests, tidal pools, ponds. Ecosystems, living communities, and their physical environment are functional units with the biomes
Organisms adapt to abiotic and biotic factors in their home
Food Chain A food chain is a diagram of relationships between living organisms. Shows living things depend on other things to live. Animals eat other animals to survive. A complex balance of life. If one animal s source of food disappears, other animals may be impacted and die.
A food web is two or more food chains hooked together
A pyramid shows relative amounts of energy available to each level.
Producers (autotrophs) are organisms that make their own food. Heterotroph s are consumers, an organism that must obtain their food from eating other organism.
1st level consumer-primary consumer usually herbivores, animals that eat plants and algae. 2nd level consumers- Secondary consumers usually carnivores, animals that eat the primary producers. 3rd level consumers- Tertiary consumer s animals that don t have predators, they are considered the top of the food chain.
Decomposers are organisms that break down other organisms. (bacteria, fungi)
A predator-prey relationship is an interaction between a consumer that hunts for another consumer for food
Omnivores are animals that eat animals and plants. Herbivores are animals that eat only plants. Carnivores are animals that eat only meat.
Scavengers feed off dead animals.
You are getting there!!!! Almost as smart as a seventh grader!!!!!
Second Week 7 th grade Light at the end of the tunnel Almost done with 7 th!
The four parts of the water cycle are evaporation, condensation, precipitation, and collection (infiltration).
In the carbon dioxide oxygen cycle, producers release oxygen for consumers who release carbon dioxide for the producers.
Nitrogen cycle is the circular path in which nitrogen moves through the environment. Nitrogen is a gas that makes up 78% of the earth s atmosphere.
Nitrates are a combination of oxygen and nitrogen, absorbed by the roots of plants Nitrifying bacteria converts ammonia from dead plants and animals and animal waste to nitrates that can be used by plants Denitrifying bacteria converts ammonia from dead plants and animals and animal waste. Nitrogen, which is released into the atmosphere Nitrogen converters combine oxygen and nitrogen to make nitrates. Ex. Lighting, bacteria in the soil, algae in wet areas Ammonia is a gas given off by dead plants and animals waste
Biomes are made up of ecosystems Each major biome includes climate range, and how well organisms have adapted. Organisms have specific structures, functions, and behaviors that enable them to survive the conditions of a particular biome
Biomes Rainforest, deserts, temperate deciduous forests, grasslands, chaparral, temperate rain forest, taiga, and tundra
Tiaga Located in the upper latitudes under tundra Cold winters and warm summers Home to conifers
Rainforest The ecosystem of the rainforest is based on the most complex interdependence of plants and animals. Tropical rainforests help maintain global rain and weather patterns. Endangered because man is cutting them down at a record pace.
Deserts Very dry Very hot during the day and cold at night Plant and animal life has adapted to the harsh conditions
Temperate Deciduous Forest This region has four season Trees loose their leaves in the fall
Grasslands They are big open area with very few bushes and trees along water Rich fertile soil
Tundra Located at the top of the world Very short summers Permafrost located about 1 meter down
Responses Plants respond to light by growing toward it or away from it (phototropism). Animals respond to cold conditions with a period of lowered metabolism (hibernation). Organisms may respond to adverse conditions with a period of lower or suspended metabolism (dormancy).
DNA DNA is a double helix molecule. DNA is a molecule that includes four different components. The arrangement of these four components within the double helix forms a chemical code
Chromosomes are strands of DNA.
Genes are sections of a chromosome that carry the code for a particular trait
Every person has dominant and recessive genes that determine the characteristics of Punnett Square their off spring
Genotype are the internal inheritable code of traits Phenotype is the observable traits
Inherited Traits Inherited traits... Rolling of the tongue Which arm you place on top when you cross your arms Attached earlobes Widow's Peak (hairline comes to a downward point in the middle)
Non-inherited Traits Non-inherited traits... Table manners Politeness Attitude
The basic laws of Mendelian genetics can explain the transmission of some traits that can be inherited from generation to generation Figure 2 : Two traits (black/white and short/long hair, with black and short dominant) show a 9:3:3:1 ratio in the F2 generation. (S=short, s=long, B=black, b=white hair) (1) Parental generation. (2) F1 generation. (3) F2 generation. Results : 9x short black hair, 3x long black hair, 3x short white hair, 1x long white hair.
Genetic engineering manipulates the genetic code to obtain a desired product Genetic engineering has numerous practical applications in medicine, agriculture, and biology
The mechanisms through which evolution takes place are a related set of processes that include mutation, adaptation, natural selection, and extinction
Mutations are inheritable changes because a mutation is a change in the DNA code
Adaptations are structures, functions, or behaviors that enable a species to survive. Adaptations are expressions of the organisms genetic information
A mutation may result in a favorable change of adaptation in genetic information that improves a species ability to exist in its environment of a mutation may result in an unfavorable change that does not improve or impedes a species ability to exist in its environment
The evidence for evolution is drawn from data including the fossil record, radiometric dating, genetic information, the distribution of organisms, and anatomical and developmental similarities across species
Natural selection is the survival and reproduction of the individuals in a population that exhibit the traits that best enable them to survive in their environment
If a species does not include traits that enable them to survive in its environment, or to survive changes in the environment, then the species may become extinct
Each environment has a population that is biodiversified
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