7th Science Chapter 1

Section 1: Getting Started/What is Life? Types of Science 1. Earth science – atmosphere, solar system, geology (rock layers, volcanoes, etc.) 2. Life science – plants, animals, other living things 3. Physical science – matter and energy – chemistry and physics

Characteristics of Life All living things have cellular organization, contain similar chemicals, use energy, respond to their surroundings, grow and develop, and reproduce Living things arise from other living things through reproduction All living things must satisfy their basic needs for food, water, living space, and stable internal conditions(homeostasis).

Characterisitcs of Life Living things = organisms Cell= basic unit of structure and function in an organism Aall organisms are composed of at least one cell (unicellular) some are many cells (multicellular). Cells are made of chemicals and the most abundant chemical is water. Carbohydrates are a cell’s main source of energy

Proteins and Lipids are building materials for cells Nucleic Acids (DNA /RNA) are the genetic material of the cell Nucleic Acids are the chemical instructions that cells meed to carry out the functions of life Metabolism= combination of chemical reactions through which an organism builds up or breaks down materials

Stimulus= Achange in an organism’s environment that causes the organism to react Response= An action (reaction) or a change in behavior due to a stimulus Growth & Development Growth= process of becoming larger Development = is a process of change that occurs during an organism’s life

Reproduction Asexual= involves only one parent and produces offspring that are identical to the parent (cloning)(Budding) (Fragmentation)(Binary Fission) Sexual= involves two parents and combines their genetic material to produce a new organism that differs from both parents.

– Living Things An organism is any living thing, no matter how big or small Examples of nonliving things: water, air, sun, clouds Living things are organized Cell – smallest unit Tissues Organ Organ system (digestive, circulatory) Organism

Some organisms are made up of only one cell, some have many cells. Living things react to their surroundings. Anything that causes some change in an organism is called a stimulus. The reaction to a stimulus is called a response. Stimuli is more than one stimulus

Homeostasis – ability to keep a balance within the body no matter what conditions are outside the body. Living things use energy Plant – use the Sun’s energy to make their own food (photosynthesis) Humans – eating food

Living things grow and develop Increase in the number and size of their cells. Living things reproduce Without reproduction the species would become extinct. Living things need a proper place to live. Raw materials – food, drink, oxygen

Where Do Living Things Come From? Biogenesis = Current Belief. Living things arise from other living things through reproduction (asexual or sexual) Spontaneous Generation= Original belief. Mistaken idea that living things can arise from nonliving sources.

Support of Biogenesis Fransico Redi – still non believers Louis Pasteur- Finally disproved spontaneous generation

Fransico Redi’s Experiment Showed that maggots laid eggs that developed into flies Controlled experiment Series of tests that are identical in all ways except for ONE factor (experimental factor) Redi’s = Type of covering over the jars- (experimental factor) only change in his experiment

Pasteur’s Experiment Developed the Swan neck flask ( experimental factor) Pasteur = worked with bacteria This was the experiment that finally disproved spontaneous generation

Solving Problems Scientific Method -State the Problem -Gather Information 5 senses – taste, touch, smell, sight, hearing Make observations -Form a hypothesis A prediction about what you think will happen

-Test hypothesis with an experiment You can only change one variable at a time! -Analyze data Set up charts, graphs, tables -Draw Conclusions Logical answer based on observations, data, and analysis Report Results Communication with other scientists

Measuring with Scientific Units Scientists use the SI system and the Metric system (based on units of 10). Length – meter (m) Volume – liter (L), centimeter cubed (cm3) Mass – gram (g) – Kilogram (Kg- SI system Temperature = Kelvin (SI) Celsius (Metric) Mass and Weight are different b/c weight measures the force of gravity on an object

Safety Most important safety rule is ask your teacher before beginning anything.

What Do Things Need to Survive? Basic Needs: food, water, living space, and a stable internal condition (homeostasis) FOOD: Autotroph = Organisims that can make their own food (photosynthesis or chemosynthesis) Heterotroph= Organism that cannot make its own food

WATER All living things need water Ability to dissolve more chemicals than any other substance on Earth. Apx. 90% of the liquid part of our blood is water

Classification Section 2 Aristotle – was one of the first people to classify organisms Plant or Animal Linnaeus – simplified the system Still use Linnaeus’s system today Binomial Nomenclature – two-word name used to classify living things It minimizes confusion among scientists System provides information about the species Taxonomy= Scientific study of how living things are classified

Biologists find taxonomy useful b/c this scientific study gives them musch information about an organism based on its classification Each genus of organisms contains noe or more species

Classification Domains - Broadest Kingdoms Phylum Class Order Family Genus Species or specific epitaph – Most Specific

Classification Based in LATIN Two Words ( Genus + Species or specific name) Capitalize ONLY the FIRST word – Genus) Second word is the Species (Not Capitalized) Written in Italics or Underlined Scientific name for humans = Homo sapien Scientific name for wolf – Canus lupus

An advantage of our scientific naming system is that biologists can communicate regardless of their native languages. Minimizes confusion

Scientific names prevent confusion. Two different organisms can NOT have the same scientific name but they might have the same common name. The easiest and most efficient field guide to use to identify an organism would be a dichotomous key. The dichotomous key uses TWO paired descriptions at each step. Taxonmic Keys- help to determine the identity of organisms

The dichotomous key has three basic functions Avoids errors in communication It classifies organisms with similar evolutionary histories together. It gives descriptive information

Classification divisions with in the domains Kingdom Phylum ( Division- Plants) Class Order Family Genus Species - most inclusive / most similar

Each level of classification is based on SHARED characteristics Family is made up of similar Order Class is made up of similar Phylum Species is made up of similar Genus Etc.. Broadest group – Domain Most Inclusive – Species Species - Organisms that are similar in structure and form and successfully reproduce among themselves.

The DOMAINS and Six Kingdoms The classification system most commonly used today separates organisms into six (6) Kingdoms Each level of classification contains all organisms that share the same characteristics

3 Domains Domain Bacteria Domain Archae Domain Eukarya

Classification Characteristics used to place an organism into a specific Kingdom Autotroph or Heterotroph Prokaryote or Eukaryote Body Form Complex Tissues

6 - Kingdoms Archaebacteria- Domain Archae Eubacteria- Domain Bacteria Protista-Domain Eukarya Fungi-Domain Eukarya Plantae-Domain Eukarya Animalia-Domain Eukarya

Characteristics -Kingdoms Cell Type - Prokaryote or Eukaryote Body Form - Unicellular/ Multicellular /Both Food Getting - Heterotrophs / Autotrophs Complex organ systems - Yes / No

Cell Type Prokaryote – No internal membrane bound organelles - No Nucleus Eukaryote – Has internal membrane bound organelles Archaebacteria - Proraryote Eubacteria - Prokaryote Protista – Eukaryote Fungi - Eukaryote Plantae - Eukaryote Animalia - Eukaryote

Evolution and Classification Species with similar evolutionary histories are classified more closely together Classifies organisms by traits and evolutionary histories By comparing body structures a scientists can get information about the evolutionary history of a species Evolution- Process of change over time Darwin- Natural Selection Shared Derived Characteristic- a trait that a common ancestor of a group had and passed it on to its descendants Branching Tree or Cladogram- shows probable evolutionary relationships. Organisms are grouped according to shared derived characteristics.

MODERN SYSTEM of CLASSIFICATION Charles Darwin Theory of Natural Selection Commonly called survival of the fittest

Can an organisim belong to the same family but to different classes Can an organisim belong to the same family but to different classes? Explain No, A family is a sub group of one order, and an order is a sub group of one class. Therefore, any two organisms that belong to the same family MUST also belong to the same class Kindom-Phylum-Class-Order-Family-Genus-Species

Why is the Protista Kingdom sometimes called the “odds and ends” or ‘Junk” Kingdom? Its members differ so much from one another and they do not fit into any of the other kingdoms. Some are autotrops and also heterotrophs and some are unicellular and multicellular

Computers use energy and respond to stimuli, such as commands from the user, Why, then are computers not considered living? Computers do not have all the characteristics of living things. They are not composed of cells. They can not reproduce. They do not grow and develop.

What are Linnaeus’ two major contributions to taxonomy? 1. Binomial Nomenclature 2. Grouping organisims based on their observable or structural characteristics