FINAL EXAM

Question 1

What is homeostasis?

Answer 1

Homeostasis is the body’s way of keeping internal conditions stable and balanced, like body temperature, blood sugar, and water levels, even when the environment changes.

Question 2

What is a negative feedback response and a positive feedback response? (homeostasis)

Answer 2

Negative feedback: The body responds by reversing a change to bring things back to normal.
Example: If your body gets too hot, you sweat to cool down.

Positive feedback: The body responds by increasing the change.
Example: During childbirth, contractions get stronger until the baby is born.

Question 3

What is the purpose of the Excretory system and the organ responsible for the most work?

Answer 3

The excretory system removes waste from the body. The kidneys do most of the work by filtering blood and making urine.

Question 4

What is the purpose of the Digestive System and some organs that are found in this system?

Answer 4

The digestive system breaks down food into nutrients the body can use.
Organs include: mouth, esophagus, stomach, small intestine, large intestine, liver, pancreas.

Question 5

What is the correct pathway for flow of air into the respiratory system?

Answer 5

Nose/Mouth → Pharynx → Larynx → Trachea → Bronchi → Lungs → Bronchioles → Alveoli (where gas exchange happens).

Question 6

What chambers would be found in the human heart, and the characteristics of blood vessels in the cardiovascular system?

Answer 6

Heart chambers: 4 total — right atrium, right ventricle, left atrium, left ventricle.

Blood vessels:
Arteries carry blood away from the heart (high pressure).
Veins carry blood to the heart (have valves, lower pressure).
Capillaries are tiny and allow exchange of gases and nutrients.

Question 7

What is the importance of the Endocrine system?

Answer 7

It controls body functions using hormones, like growth, metabolism, and mood. It helps keep everything balanced over time.

Question 8

What are the two divisions of the skeletal system?

Answer 8

Axial skeleton: skull, spine, and rib cage (center of the body).

Appendicular skeleton: arms, legs, pelvis, and shoulder bones (movement).

Question 9

What are the 3 different types of muscle tissue and their locations?

Answer 9

Skeletal muscle: attached to bones (voluntary movement).

Smooth muscle: found in organs like stomach and intestines (involuntary).

Cardiac muscle: found only in the heart (involuntary, pumps blood).

Question 10

What tissue is found in the nervous system?

Answer 10

Nervous tissue — made of neurons (nerve cells) and glial cells (support cells).

Question 11

How is the nervous system divided into smaller systems?

Answer 11

Central Nervous System (CNS): brain and spinal cord.
Peripheral Nervous System (PNS): all other nerves.
The PNS is further divided into:
Somatic system (controls voluntary actions)
Autonomic system (controls involuntary actions, like heartbeat)
Autonomic is further split into:
Sympathetic (fight or flight)
Parasympathetic (rest and digest)

Question 12

Define a pathogen

Answer 12

A pathogen is any microorganism—like a virus, bacteria, fungus, or parasite—that can cause disease.

Question 13

Explain parasitic and contagious

Answer 13

Parasitic: An organism that lives in or on another organism (host) and harms it while benefiting itself.
Contagious: A disease that can spread easily from one person to another.

Question 14

What are the 3 different shapes bacteria can form?

Answer 14

Coccus (round/spherical)
Bacillus (rod-shaped)
Spirillum (spiral-shaped)

Question 15

What do bacteria use to help protect them?

Answer 15

Bacteria have a cell wall and sometimes a capsule to protect them from the environment and immune system.

Question 16

What is binary fission?

Answer 16

Binary fission is how bacteria reproduce—one bacterial cell splits into two identical cells.

Question 17

How do antibiotics work?

Answer 17

Antibiotics kill or stop the growth of bacteria by targeting their cell walls or other vital processes—but they do not work on viruses.

Question 18

How are viruses structured?

Answer 18

Viruses have:

Genetic material (DNA or RNA)
A protein coat (capsid)
Some have an outer envelope made of lipids

Question 19

Explain how a virus infects a cell and uses a cell

Answer 19

A virus attaches to a host cell, injects its genetic material, and takes over the cell’s machinery to make more viruses. The cell often bursts, releasing the new viruses.

Question 20

What does latent mean when referencing a virus?

Answer 20

Latent means the virus is inside the body but inactive—it hides in cells and can reactivate later (like the herpes or chickenpox virus).

Question 21

Explain the first line defenses of the immune system?

Answer 21

Skin blocks entry
Sweat washes microbes away
Snot (mucus) traps germs in your nose/throat

Question 22

What would be classified as the second line of defense for the immune system?

Answer 22

Think: Non-specific attack

Phagocytes = “Pac-Man” cells eat germs
Inflammation = red, swollen, hot → more immune cells rush in
Fever = turns up heat to slow germs
Interferons = virus blockers

Question 23

What contributes to the third line of defense for the immune system?

Answer 23

B-cells make antibodies (tag invaders)
T-cells destroy infected cells
Memory cells remember the invader so your body can fight it faster in the future

Question 24

What do B-cells produce for the immune system and what do T-cells produce for the immune system?

Answer 24

B-cells → Antibodies
T-cells → Help, Kill, or Remember

Question 25

How does Active Immunity differ from Passive Immunity and give examples?

Answer 25

Active = You Make It From sickness or vaccine Long-lasting memory Passive = Borrowed Help From mom (breast milk) or injection Temporary protection

Question 26

What is an allergy?

Answer 26

An allergy happens when your immune system thinks something harmless is dangerous — like pollen, dust, or certain foods.

Question 27

What is the importance of T-helper cells?

Answer 27

Start the immune fight Tell B-cells + killer T-cells what to do Without them = weak immune response

Question 28

Define ecology and population ecology.

Answer 28

Ecology The study of how organisms interact with each other and their environment. Population Ecology The study of groups of the same species (populations), how they grow, and how they interact with the environment.

Question 29

Explain the three different types of population distribution patterns.

Answer 29

Clumped – group together (ex: fish in schools) Uniform – spaced evenly (ex: penguins nesting) Random – scattered randomly (ex: dandelions)

Question 30

How is the growth rate of a population calculated? When would the growth rate be positive and when would the growth rate be negative?

Answer 30

Births - Deaths + Immigration - Emigration Positive growth = more born/coming in than dying/leaving Negative growth = more dying/leaving than born/coming in

Question 31

What is carrying capacity of a population?

Answer 31

The maximum number of individuals an environment can support without running out of resources (like food, space, water).

Question 32

What factors that affect populations would be classified as density dependent factors and density independent factors?

Answer 32

Density-Dependent (depends on population size): Competition Predation Disease Food supply Density-Independent (affects no matter what size): Natural disasters Weather Pollution Human activity

Question 33

What happens if a population goes over carrying capacity?

Answer 33

Resources run out Death rate increases Population crashes or declines

Question 34

Define community ecology, habitat and niche.

Answer 34

Community Ecology Study of how different species in an area interact. Habitat The physical place where an organism lives. Niche An organism’s role or job in the environment (what it eats, where it lives, when it's active, etc.)

Question 35

What are some defenses that prey have adapted in response to predators?

Answer 35

Camouflage Mimicry (looking like something else) Poison Speed or hiding Warning colors (like bright red or yellow)

Question 36

What are the 3 different types of symbiosis?

Answer 36

Mutualism – both benefit (🐝 + 🌸) Commensalism – one benefits, other unaffected (barnacles on whales) Parasitism – one benefits, one is harmed (tick on a dog)

Question 37

What is the importance of a keystone species?

Answer 37

If removed, the ecosystem changes drastically or collapses. Example: sea otters, wolves, bees

Question 38

How does species richness and species diversity relate?

Answer 38

Species Richness = number of different species in an area Species Diversity = richness + evenness (how balanced those species are)

Question 39

What is an ecosystem?

Answer 39

All the living (plants, animals) and non-living (water, air, soil) things in an area, and how they interact.

Question 40

What is Climate?

Answer 40

Climate is the average weather (temperature, rain, wind, etc.) in a region over a long time (decades or more).

Question 41

What is Solar Irradiance and how does it affect biodiversity?

Answer 41

It's the amount of sunlight a place gets. More sunlight = more energy for plants, which supports more animals = more biodiversity Near the equator = high irradiance = high biodiversity (like rainforests)

Question 42

How does the water cycle affect climate?

Answer 42

The water cycle (evaporation, condensation, precipitation) moves heat and moisture around Earth. It influences rainfall, humidity, and temperature, which all shape the climate.

Question 43

Explain the nitrogen and phosphorus cycles?

Answer 43

NITRO- Nitrogen in air → fixed by bacteria → plants use it → animals eat plants → returns to soil when organisms die. Needed for proteins and DNA. PHO- Found in rocks → released into soil/water → taken by plants → eaten by animals → returns through waste/death. Needed for bones and ATP (energy).

Question 44

What are the different levels of the food chain?

Answer 44

Producers (plants) Primary consumers (herbivores) Secondary consumers (eat herbivores) Tertiary consumers (top predators) Decomposers (break down dead stuff)

Question 45

What is a trophic pyramid and how much energy is transferred from each level?

Answer 45

Shows energy flow in food chain Only 10% of energy is passed to the next level--90% is lost as heat

Question 46

What is a food web vs a food chain?

Answer 46

Food chain = straight line: who eats who Food web = many chains connected → more realistic

Question 47

How is energy cycled in an ecosystem?

Answer 47

Starts with the sun → moves through organisms → ends as heat Matter (like carbon, nitrogen) cycles, but energy flows one way

Question 48

What are the characteristics for a tundra and desert?

Answer 48

Tundra Cold, dry, frozen soil (permafrost) Small plants, few animals Desert Hot OR cold, always very dry Cacti, reptiles, animals active at night

Question 49

How does a tropical forest, temperate forest, boreal forest and chaparral compare?

Answer 49

Tropical forest – Hot, wet, and full of life all year. Tall trees, highest biodiversity. Temperate forest – 4 seasons. Trees lose leaves. Rich soil and common wildlife. Boreal forest (Taiga) – Cold, snowy. Evergreen trees. Animals like moose and wolves. Chaparral – Hot, dry summers. Shrubs, not trees. Fires are common.

Question 50

What are the characteristics of a savannah, prairie and steppe?

Answer 50

Savanna – Warm, grassy with few trees. Wet/dry seasons. Lions, elephants. Prairie – U.S. grasslands. Rich soil, few trees. Bison and prairie dogs. Steppe – Cold, dry grassland in Asia. Short grasses. Harsh winters.

Question 51

What are the characteristics of lake, river and wetland?

Answer 51

Lake – Still water. Fish, algae. Temperature layers. River – Flowing water. Moves nutrients. Lots of life. Wetland – Swampy areas. Filters water. Home to birds and amphibians.

Question 52

How does oceans, coral reefs and estuaries compare?

Answer 52

Ocean – Big, salty, and deep. Huge range of life. Coral reef – Warm, shallow ocean. Super biodiverse. Needs clean, warm water. Estuary – Where river meets ocean. Mix of salt + fresh water. Fish nurseries.

Question 53

What is an endangered species compared to a threatened species?

Answer 53

Endangered species are at high risk of extinction soon—they’re in serious danger. Threatened species aren’t in immediate danger, but they’re likely to become endangered if nothing changes.

Question 54

What is critical habitat of endangered species?

Answer 54

Critical habitat is the specific area an endangered species needs to survive—this includes places for shelter, breeding, and finding food. Protecting this space is key to saving the species.

Question 55

How many mass extinctions has Earth experienced?

Answer 55

Earth has had five mass extinctions in the past. Scientists warn we might be in the sixth now—this one caused mostly by human activity.

Question 56

What are the main reasons for extinction that are being caused by humans?

Answer 56

An easy way to remember is HIPPO: Habitat loss (cutting down forests, building cities) Invasive species (non-native species taking over) Pollution (air, water, soil contamination) Population growth (too many people using too many resources) Overharvesting (overfishing, hunting, poaching)