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Balancing human needs with the needs of the biosphere
- Restricted use of ozone-depleting chemicals
What is the difference between the Greenhouse Effect and Global Warming?
- Greenhouse Effect - A natural, beneficial process that raises the Earth's temperature 50-75 degrees F - a good thing.
- Global Warming - The average temperature rose about 1.1 degrees F during the 20th century.
Evidence that supports the hypothesis that humans are adding greenhouse gases to the atmosphere and thus contributing to climate change.
- Amount of CO2 in the atmosphere has been rising
- Temperature has been rising
- Adding "new" CO2 into the atmosphere by burning fossil fuels, increasing the amount of CO2 in the atmosphere
What are some of the predictions and impacts of climate change?
- Sea Level Rise
- Floods and droughts
- Decrease in water resources
- Pestilence and death
What is the cause of the depletion of the ozone layer? How are we reversing this problem?
- Cause - Compounds called chlorofluorocarbons (CFCs)
- Reversing - Montreal Protocol - restricting the use of ozone-delpeting chemicals
Why is there concern about the current rate of extinction? What are dams a concern?
- Concern - 7th mass extinction is underway, by 2100 over half of the animal and plant species could be extinct
- Dams - Change a river ecosystem to a lake ecosystem and block fish that are migrating to spawning grounds
Why is sustainable development important for our future?
We need to realize that we need healthy ecosystems for our survival
What is HIPPO?
- H - Habitat destruction
- I - Invasive species
- P - Pollution
- P - Population
- O - Over-harvesting
Descent with Modification
- All organisms are related through descent from some unknown species that lived in the remote past
- Organisms have adapted and have been modified over time
Those individuals with inherited characteristics best suited fro the local environment, generally, will leave the greatest number of surviving, fertile offspring.
"Survival of the Fittest"
The ability of an organism to: Survive the reproductive age, produce viable offspring, and only need to be "strong" enough or "fit" enough to pass on their genes to the next generation.
Carbon-12 and Carbon-14 are used to date rocks
What 2 observations lead him to come to the conclusion of his theory of natural selection?
- 1) Overproduction of offspring, resulting in a struggle for existence
- 2) Individual variation (individuals within a species vary in many inheritable traits)
Why is HIV able to adapt around (become resistant) to medicines and a person's immune system?
Reverse Transcriptase (RT) - The enzyme that does this makes lots of errors in making DNA
5 Evidences given for evolution
- 1) Fossil Record - The younger fossils are on top of older ones
- 2) Biogeography - The study of geographic distribution of a specie. (Continental Drift)
- 3) Comparative Anatomy - Homologous structures - Structures that are similar in different species of common ancestry
- 4) Comparative Embryology - Different species look similar in embryo development
- 5) Molecular Biology - Closer species share a greater proportion of their DNA and protein sequences than more ones. (Identical twins = 100%)
What makes up a prokaryote?
- Nucleoid region
- Bacterial cell wall
What are the 3 shapes of bacteria?
- Bacilli = Rods
- Cocci = Round
- Spirochetes = Spiral
According to the fossil record, how long have bacteria been around?
3.5 billion years ago
What is the role of cyanobacteria and other photosynthetic bacteria for life on Earth?
They helped to change the atmosphere of the Earth from one with little oxygen to one with 22% oxygen.
Microorganisms that cause disease
- Factors that intensify the effect of a pathogen:
- Producing toxins
- Producing endospores
- Attacking cells of the immune system
- Having a capsule
- Molecules that biological processes or attack key systems
Poisons produced and secreted by the bacteria
Toxic materials that are part of the cell walls of certain bacteria
- An inner cell within the bacterial cell
- Has a thick, protective coat that allows them to survive in very harsh environments for long periods of time
Using prokaryotes to decompose harmful materials to harmless materials
- Anthrax - Inhaling spores is the most deadly
- The Plague - Produces endotoxins and sometimes exotoxins / able to evade the immune system
- Small Pox - Able to evade the immune system / virus
Why is bacteria beneficial to us most of the time? 4 examples.
- We depend upon bacterial for a lot of things:
- In our intestines - Proper functioning of intestines, help break down food, provide vitamins
- Chemical decomposing and recycling
- They help provide the oxygen we need
What is the role of bacteria in chemical decomposing and recycling?
- They return vital chemical elements to the environment in the forms used by plants
- They break down waste into harmless smaller molecules and elements
What causes some bacteria to be harmful?
- Pathogens with virulence factors
- Bacteria produce toxins
The ability to protect against disease-causing agents
A substance that triggers an immune response such as pollen, bacteria, virus, or fungi
An antigen capable of causing disease such as bacteria, virus, or fungi
The mixture of microbes regularly found on or in may sites of our bodies
Mucous membranes in our nose and throat
Form a protective covering that resists penetration and traps many microbes
What is the role of the first line of defense?
Keep anything foreign out
What are the first line of defense components?
- Intact skin
- Normal Flora
- Mucus Membranes
- Protective Membranes
- Anti-microbial Factors
- Acid in stomach
- Low pH in parts of intestine and urine
What are the physical barriers that protect us in the first line of defense?
- Intact Skin
- Normal Flora
- Mucus Membranes
- Protective Membranes
What is the role of intact skin in the first line of defense?
Bacteria and viruses cannot penetrate intact skin, but they can enter through cuts
What is the role of normal flora in the first line of defense?
- Skin, mouth, nose, eyes, ears, intestines
- Act as protection by keeping more harmful bacteria and fungi from growing on these surfaces
What is the role of mucous membranes in the first line of defense?
Membranes of the eyes, respiratory, digestive, and urogenital systems form a protective covering that resists penetration and traps many microbes.
What is the role of coughing and sneezing in the first line of defense?
They expel the microbes
What is the role of peristalsis in the first line of defense?
Keeps food and microbes moving along within our digestive system
What are modes of transmission?
- Bacteria and viruses have a variety of ways to get from one person to another in order to reproduce
- Food, coughing and sneezing, feces, blood, insects, and sexual activity
What are some of the chemical barriers?
- Anti-microbial Factors
- Acid in stomach
- Low pH in parts of intestines and urine
Rhythmic waves of contractions by muscles in the intestines keep things (food and microbes) moving along within our digestive system
Wander through body fluids and engulf and destroy foreign cells
- White blood cells
- Most prevalent and very effective at destroying extracellular antigens
System of veins that parallels the circulatory (blood) system
- A response to an infection
- Red, warm, swollen area of skin
Circulate in blood plasma and have several roles
What is the role of the 2nd line of defense?
General, non-specific response to infection
What are the components of the 2nd line of defense?
- Immune Cells
- Lymphatic System
- Anti-microbial Proteins
What is the function of phagocytic cells? How do they operate?
- Wander through body fluids and engulf and destroy foreign cells
- Macrophages are most prevalent and very effective at destroying extracellular antigens
What is the lymphatic system? What is its role in the immune system? What do lymph nodes do?
- A system of veins that parallels the circulatory (blood) system
- Functions - Returns the fluid between cells (interstitial fluid) to the circulatory system; Monitor the fluids for pathogens and cancer cells
- Lymph Nodes - Found throughout the body which filter the lymphatic fluid, filled with immune cells
What is inflammation? What is the role of fever in fighting infections?
- Inflammation - A response to an infection
- Fever - Systemic (whole body) response to infection, thought to help immune cells perform more efficiently and hinder the growth of bacteria
How does complement protein help protect us?
- Circulate in blood plasma and have several roles
- Coat the surfaces of microbes marking them for destruction by macrophages
- Others join together to make lethal holes in microbial membranes, causing them to die
- We acquire immunity
- It develops over our lifetime as we get sick or vaccinated
This system protects primarily against extracellular bacteria and viruses present in body fluids
These cells attack viral-infected body cells (intracellular) and cancerous cells
- "Y" shaped protein molecule that bind to different antigenic determinants
- They counteract antigens
- Make antibodies
- Make about 2,000 antibodies a second, which is how our immune system attempts to catch up with bacteria
Helper T Cells
When they are stimulated, they released chemicals to direct the entire immune response
Cytotoxic T Cells
- Bind to and attack virus-infected or cancer cells
- After binding, they release protein molecules that make holes in the membrane of the infected cell
"Trick" the immune system into a primary immune response - making memory cells, which protect you for life
Antigens that cause allergies
Release histamines in allergic reactions
When released, it causes allergic reactions
Mast cells release their histamines very suddenly, in great amounts, causing blood vessels to dilate rapidly and the blood pressure drops severely
What is the role of the 3rd Line of Defense?
Specific response with memory
What are the components in the 3rd Line of Defense?
- B Cells (Plasma cells and memory cells)
- T Cells (Helper T cells and Cytotoxic T cells)
What are the 2 characteristics of acquired immunity?
- Acquired - Develops over our lifetime
- Passive - Comes from outside (Breast feeding)
Why are specificity and memory so important?
3rd Line of Defense protects us against specific pathogens and develop and retain memory, so we don't get the same sickness again
What happens on the first exposure to an antigen? Second exposure? Why are we protected for life after the first exposure?
- 1st - When an antigen comes along and binds to the antibody, the B cell is stimulated to divide into plasma cells and memory cells
- 2nd - Many memory cells that are looking for that pathogen for the rest of your life with little or no sickness
Once these cells encounter this antigen the cells mount an attack and create numerous memory cells that will be looking for this antigen in the future
From what types of microorganisms do B cells protect us?
Extracellular bacteria and viruses
How do vaccines work?
- "Trick" the immune system into primary immune response - making memory cells, which protect you for life
- The secondary response provides the same protection as encountering the live bacteria or virus, but you don't have to get sick.
What causes allergic reactions? What chemical do Mast Cells released causing inflammation?
- Mast Cells - Histamine and other chemicals that trigger the inflammatory response
What are antibiotics? How do they differ from antibodies?
- Antibiotics - Prevent bacteria from building their cell walls and are useless against viruses
- Antibodies are produced by your body to attack any foreign substance that invades your body.
- Antibiotics are external chemicals that kill germs or help your body fight them.
What makes HIV so dangerous? Why does the immune system have trouble fighting HIV?
- Dangerous - It attacks the Helper T cell, which directs immune response and it becomes less effective when it is infected. Cytotoxic T cells will attack and destroy infected Helper T cells
- Trouble - It mutates so quickly that it can change the parts that the immune system "recognizes"