Class 4.

DISCUSSION

In groups of two or three discuss the following points and report back to the class on your major conclusions.

1. Do you know how to read about science, not to learn about science?

2. Are you experienced in reading and interpreting graphs?

3. What does the geosciences subject area contain?

4. Are you familiar with a process of a scientific inquiry?

5. What subject areas do physical sciences include?

6. Do you think you need a quick or thorough science review?

SCIENCE: BIOLOGY, GEOSCIENCES, PHYSICAL SCIENCES

PRE-READING ACTIVITIES

Vocabulary enrichment

Biology Terms Review

Cellular Biology

Cells

organism ( higher, multicell)

cell (advanced, eukaryotes)/,( first, primitive, prokaryotes)

blood, cancer, germ, nerve = neurons, line, wall) cell

egg cell/sperm

(blue-green) algae

nuclear membrane

cytoplasm

mitochondria

ribosome

nucleus — nuclei

vacuole

chloroplast

Reproduction (animal, human, plant)

Mitosis — meiosis

carbon copy

duplicate Syn: double

zygote

Photosynthesis

carbohydrates

chlorophyll

hydrogen

Cell Activities

respire Syn: breathe// exhale

substances

equilibrium Syn: balance

oxidation

fermentation

Respiration (aerobic/anaerobic)

Ingestion

Digestion

Secretion

Excretion

Homeostasis

Genes (Dominant, Recessive) Dna, Rna

Biology of Organisms and Evolution

molecule

organism

mammals

insects

species

freed

vertebrate (backbone)

invertebrate Syn: spineless

natural selection

primate

Cell Classification

bacterium — bacteria Syn: virus

parasite

protein

Human Biology

chromosomes

hormone

neuron

enzyme Syn: ferment

contaminate

transmit

tissue

intestine

nutrient

artery

capillary

cartilage

Systems

Digestive

Circulatory

Skeletal

Muscular

Nervous

Excretory

Respiratory

Endocrine

Immune

Ecology

subdominant individuals

predation

predominant Syn: superior, ascendant, prevalent

biome

ecosystem

Life Cycles

evaporation

condensation

precipitation

carbon cycle

READING ACTIVITIES

Use the review material to learn how to read about science, not learn about science. There are about 12 science items on the LAST. Many of the items are reading comprehension items. Other items are about reading and interpreting charts and graphs.

I. Biology Review

CELLULAR BIOLOGY. CELL ACTIVITIES

The cell is the basic unit of all living things. A cell may be an organism by itself or the basic building block of a multicell living organism. Animal and plant cells are different. Most cells that make up living things are eukaryotes. The second type of cells are called prokaryotes. Most prokaryotes are bacteria or blue-green algae.

All cells have a cell membrane at the outer edge of the cell. A gel-like cytoplasm throughout the interior of the cell protects the different cell organs inside the cell. A nucleus, the cell’s brain, inside the cytoplasm is protected by a nuclear membrane. The nucleus contains chromosomes. The golgi apparatus make, store, and distribute hormone and enzyme materials. The mitochondria process food into energy. Plant cells have a thicker cell wall outside the membrane. Plant cells also contain chloroplasts where photosynthesis takes place.

Cells must reproduce to survive. There are two methods of cell reproduction — mitosis and meiosis. In mitosis, cells make a carbon copy of themselves and create duplicate chromosomes. The chromosomes migrate to opposite sides of the cell; then the cell splits, making an exact copy of itself.

Higher multicell organisms reproduce sexually. In these organisms, the sperm and egg cells combine in a process called meiosis. Meiosis begins with egg and sperm cells, each with half the number of chromosomes. When the sperm and egg cells combine, a single cell, zygote, is created with a complete (diploid) set of chromosomes. This single cell develops into the advanced organism, a human.

Photosynthesis occurs within plant cells to create carbohydrates, water, and oxygen needed by the plant. Photosynthesis occurs in two stages:

1) In the presence of light and chlorophyll, carbon dioxide and water are broken down;

2) Carbon combines with oxygen and hydrogen to form carbohydrates. Light is not needed for this stage.

Cells create energy through respiration. This process, which occurs in the mitochondria, can be either aerobic or anaerobic. Aerobic respiration is the oxidation of food, which takes place in the presence of oxygen. Anaerobic respiration is fermentation, which takes place without oxygen.

Ingestion Take in food.

Digestion Break down food to usable forms.

Secretion Create and release useful substances.

Excretion Eliminate waste material.

Homeostasis Maintain the cell’s equilibrium.

A chromosome is a rodlike structure located in the cell nucleus. Genes carry specific bits of genetic information. Each gene occupies a specific location on one of the chromosomes. Deoxyribonucleic acid (DNA) is the genetic material found tightly coiled in a gene. DNA provides the genetic codes that determine many traits of an organism. The gene also contains very large quantities of noncoding DNA, which does not affect the makeup of an organism. The DNA creates ribonucleic acid (RNA). The DNA cannot leave the nucleus; RNA serves as the messenger that carries the genetic code throughout the cell.

BIOLOGY OF ORGANISMS AND EVOLUTION. CELL CLASSIFICATION

There was very little oxygen in the earth’s atmosphere about 3. 5 billion years ago. Research has shown that atoms can combine spontaneously in this type of environment to form molecules. This is how life may have begun on earth about 3. 4 billion years ago.

Eventually these molecules linked together in complex groupings to form organisms. These earliest organisms must have been able to ingest and live on nonorganic material. Over a period of time, these organisms adapted and began using the sun’s energy. When photosynthesis released oxygen into the oceans and the atmosphere, the stage was set for more advanced life forms.

The first cells were prokaryotes (bacteria), which created energy (respired) without oxygen (anaerobic). The next cells to develop were blue-green algae prokaryotes, which were aerobic (created energy with oxygen) and used photosynthesis. Advanced eukaryotes developed from these primitive cells. It took about 2. 7 billion years for algae to develop. When this simple cell appeared 950 mil­lion years ago, it contained an enormous amount of DNA. This very slow process moved somewhat faster in the millennia that followed as animal and plant forms slowly emerged.

Animals developed into vertebrate (backbone) and invertebrate (no backbone) species. Mammals became the dominant vertebrate species, and insects became the dominant invertebrate species. As animals developed, they adapted to their environment. Those species that adapted best survived. This process is called natural selection. Entire species have vanished from the earth. Mammals and dinosaurs coexisted for over 100 million years. During that time, dinosaurs were the dominant species. When dinosaurs became extinct 65 million years ago, mammals survived. Freed of dinosaurian dominance, mammals evolved into the dominant creatures they are today. Despite many years of study, it is not known what caused the dinosaurs to become extinct or why mammals survived.

Humans are in the primate (upright) family of mammals. Very primitive primates, along with other mammals, were found on earth before the dinosaurs became extinct. Tools are a mark of the advanced adaptation of a species. Stone tools found in association with early humanoids date back about 2 million years. Sites dated 1 million years old show marks caused by humanlike use of tools. Scientists believe that early sapiens developed about 250,000 years ago and that modern Homo sapiens developed about 75,000 years ago. The ability to communicate is a sign of advanced development. Many forms of nonverbal communication have probably existed since the appearance of Homo sapiens. Scientists speculate that speech distinct from animal sounds probably occurred about 30,000 years ago. Writing first appeared about 6,500 years ago.

Living things are generally classified into five kingdoms. Two kingdoms are dedicated to one-celled living things (prokaryote or eukaryote). There are three kingdoms of multicelled eukaryotes based on whether nutrition is obtained through absorption, photosynthesis, or ingestion.

The Moneran kingdom includes all prokaryotes. The organisms include bacteria and algae. These microscopic organisms are limited to respiration and reproduction.

The Protistae kingdom includes all single-celled eukaryotes. These organisms include algae and protozoa. These cells have a fully functional organ system and get their through photosynthesis.

The Fungi kingdom includes multicelled eukaryotes that gain their nutrition through absorp­tion. These organisms include mushrooms and are rootlike with caps and filaments.

The Plantae kingdom includes multicelled eukaryotes that gain their nutrition through pho­tosynthesis. These organisms have thicker cellulose cell walls.

The Animalae kingdom includes multicelled eukaryotes that gain their nutrition through ingestion. Most of these organisms are mobile at some time in their existence.

Bacteria are small, single-celled organisms (prokaryotes) found everywhere in the environment. As noted already, bacteria were among the earliest organisms to develop. Bacteria are classified as bacilli (rod-shaped), cocci (circular or spherical), and spirilla (coiled). Bacteria that can move “swim” with flagella.

One type of bacteria live on dead animal and vegetable material. Without the decomposition these bacteria bring, the earth would quickly be covered with dead organic material. A second type of bacteria is a normal part of living tissues and is often needed for regular physiological processes. The third type, parasites, destroy the organisms in which they live. About 200 types of bacteria cause diseases in humans.

A virus is a bit of genetic material surrounded by a protective coat of protein. The virus itself is lifeless, lacks the ability to reproduce, and is not classified in one of the five kingdoms. Viruses cannot be seen in even the most powerful regular microscope. The smallest virus is about one millionth of a centimeter long. Viruses are parasitic and remain a major challenge in battling infectious diseases. Once in a living cell, a virus can send its own genetic material into the cell, reproduce, and do significant damage to the host cell and the host organism.

HUMAN BIOLOGY. HUMAN BODY SYSTEMS

Humans have 23 pairs of chromosomes. Females typically have 23 similar pairs including a pair of X chromosomes. Males typically have 22 similar pairs and one X and one Y chromosome. Genes carry specific bits of genetic information. Each gene occupies a specific location on one of the chromosomes. Researchers today have identified and mapped the exact location of more than 200 genes. Scientists can even identify whether or not a person has certain hereditary traits.

Diseases compromise the body’s defense system. Most diseases can be recognized by symp­toms that may include fever, aches and pains, fatigue, growths, changes in blood cell composi­tion, and high blood pressure. Many infectious diseases, including pneumonia and infections in cuts, are caused by bacteria. Other infectious diseases, including measles and influenza (flu), are caused by viruses. Envi­ronmental causes of disease include smoking, a high-fat diet, and pollution. Other diseases may result from genetic or occupational causes and abnormal cell growth. Many diseases are related to mental disorders or stress.

Acquired Immune Deficiency Syndrome (AIDS) is a disease caused by the HIV virus that attacks the body’s immune system. Current research indicates that all those with AIDS will die as a result of this virus. The HIV virus is transmitted through blood and bodily fluids, including those fluids associated with intimate sexual contact. Intravenous drug users who share needles may become infected with the virus by injecting small amounts of contaminated blood. Parts of the human body are made up of highly specialized cells. These cells combine to make tissue. Some tissues combine to form organs. Various organs combine in systems that enable the body to function: Cells >Tissue > Organ > Organ System >Body.

1. Digestive System. Food is usually taken in through the mouth. The teeth and tongue break the food down mechanically, and the saliva begins the digestive process. When food reaches the stomach, the stomach churns to mix the food while digestive enzymes break down the proteins. The semiliquid, digested food moves into the small intestine. Nutrients are absorbed through the small intestine into the bloodstream. Waste and undigested food move into the large intestine. The large intestine carries the; waste and undigested food to the rectum.

2. Circulatory System. The circulatory system carries oxygen and nutrients throughout the body. A four-chambered heart pumps blood through the circulatory system. Oxygenated blood is pumped through the left side of the heart, through arteries to capillaries and then to cells. The right side of the heart pumps oxygen-poor blood back to the lungs.

3. Skeletal System. The bones (about 200) and cartilage that make up the skeletal system provide form and rigidity to the human body. A series of joints throughout the skeleton provide flexibility. Bone is living, rigid tissue. Cartilage is found at bone joints, such as the knee, and makes up the nose and other rigid parts of the body.

4. Muscular System The muscular system consists of skeletal (striated), smooth, and cardiac muscles. Most skeletal muscles are attached to the skeleton by tendons. These muscles are called voluntary muscles because they can be controlled consciously and make up most of human flesh. Smooth muscle is involuntary and is found in large blood vessels, internal organs, and the skin. Cardiac muscles are an involuntary muscle found only in the heart.

5. Nervous System The nervous system receives stimuli, transmits electrochemical signals, and activates muscles. Receptors in the skin and elsewhere in the body receive stimuli. Nerve cells, called neurons, send signals to the central nervous system. Dendrites in the cell transmit signals, while axons receive stimuli. The central and peripheral nervous systems form a single operating system. The central nervous system includes the brain and spinal cord. The peripheral nervous system connects the central nervous system to the rest of the body. The autonomic nervous system is connected to the central nervous system and controls circulation, respiration, digestion, and elimination.

6. Excretory System The excretory system consists of the kidney, bladder, and connecting tubes. Nephrons in the kidney collect liquid wastes. The liquid wastes are transferred to the bladder and leave the body as urine through the urethra.

7. Respiratory System Respiration delivers oxygen to the bloodstream. Nasal passages clean and warm the air on its way to the lungs through the trachea and bronchi. Air is collected in the alveoli, which transfers oxygen and other gases to the bloodstream;

8. Endocrine System The endocrine system is a complex system that produces and distributes hormones through the bloodstream. The system consists of glands that secrete hormones and other substances;

9. Immune System The immune system resists the spread of disease by destroying disease-causing agents (antigens). This system is exceptionally complex and not fully understood. Normally, a combination of the following immune responses is needed to defeat an antigen. The lymphatic system produces lymphocytes in bean-sized lymph glands located throughout the body. The lymphocytes are transported throughout bodily tissue by lymphatic capillaries. Lymphocytes control the immune system and kill antigens directly. Granulocytes are very numerous. They ingest antigens already killed by cell enzymes. Monocytes exist in small numbers. They ingest and kill antigens and more importantly alter antigens in a way that makes it easier for lymphocytes to destroy them. Immunoglobins (antibodies) combine with antigens to remove them from the body. There are thousands of antibodies, each targeted for a specific antigen. Other proteins called cytokines complement proteins and aid the immune response.

ECOLOGY. LIFE CYCLES

Ecology refers to the relationship between organisms and their ecosystem (habitat). An ecosystem includes interdependent life forms and supports life through food, atmosphere, energy, and water. Organisms, including plants and animals, interact with and adapt to their ecosystem. Earth is surrounded by a thin layer of atmosphere. Within that atmosphere lies earth’s biosphere where life exists. The biosphere contains a number of biomes or living areas. Aquatic biomes include ocean, shallow water, and tidal marshes. Land biomes are classified by the predominant form of plant life and include forest, grassland, and desert. Each organism in a biome occupies a place in the food web. Each organism, at some point in its life or death, is food for some other organism, in this way; energy is transferred among organisms in the biome. A community refers to the interdependent populations of plants and animals. The dominance of one species in a community can affect the diversity (number of species and specie members). The community includes the habitat where a particular plant or animal lives and its niche (role).

Within a community, the primary interactions are predation (including parasitism) and cooperation. Predators and prey adapt and develop more effective ways of hunting or defense. Cooperation may develop due to the dependence of one organism on another. Organisms may compete within their species or with other species for resources. Successful competitors survive and become dominant. Subdominant individuals either accept poorer habitats, give up the resources, migrate, or perish. A number of essential life cycles take place on earth:

1. Water Cycle Most of the earth’s water is salty, but humans need fresh water to survive. Fresh water is renewed through the water cycle. The cycle consists of three phases: evaporation, condensation, and precipitation. Evaporation occurs when heat from the sun changes ocean water and some water from other sources, into water vapor. Condensation follows when water vapor turns into water droplets, which form clouds. Precipitation occurs when the droplets become too heavy and water falls as rain, snow, sleet, or hail.

2. Oxygen Cycle Humans and other animal organisms need oxygen to survive. Plants give off oxygen. An appropriate balance between plant photosynthesis and animal respiration ensures that enough oxygen is available.

3. Carbon Cycle Carbon is used by all living things. Plants need carbon dioxide for photosynthesis. Animals get the carbon from the plant tissues they eat and exhale carbon dioxide as a by product of respiration. Here again, the balance between animal respiration and plant photosynthesis ensures that enough carbon will be available. In recent times, however, industrialization has added extra carbon to the atmosphere, jeopardizing the balance of this cycle.

Air, water, and soil pollution are serious environmental problems. Some lakes, rivers, and streams are so polluted they can not be used by humans. Fish from many of these waters cannot be eaten. Air in some areas has been very polluted by factories and power plants, which use sulfur based fuels such as oil and coal. Land has been polluted by dumping hazardous wastes, including radioactive wastes. All forms of pollution lead to disease and premature death.

POST-READING ACTIVITIES