Biology Honors Unit 1 - Nature of Science and Homeostasis

What are the 7 characteristics of life?

Organization, Regulation, Reproduction, Metabolism, Response to Stimuli, Growth and Development, and Evolution

Organization

organization of one or more cells into complex structures that carry out life functions. Made out of cells.

Regulation/Homeostasis

the ability of an organism to control inner conditions despite the environment around them.

Reproduction

the biological process by which new individual organisms are produced, ensuring the continuation of a species, by passing down genes.

Energy Processing/ Metabolism

The ability to obtain and use energy.

Response to Environment/Stimuli

the ability of an organism to detect and react to changes in its environment to maintain homeostasis.

Growth and Development

the process by which organisms increase in size and undergo changes throughout their life cycle, using their DNA and genetic material.

Adaptation/Evolution

the process by which organisms change over time through variations and natural selection, allowing them to better survive and reproduce in their environment.

How many of the 7 characteristics do organisms need to be considered alive?

All 7

True or false? The 7 characteristics are based off of individuals, not their general species.

False. it is based off the species and it isn’t personal. Because some individuals could have defects or diseases that make them different.

What are the 3 types of living things?

1. Thriving - they are currently alive, like a human.

2. Dormant - Things that are “dead” right now but if nourished properly they can come alive again. For example, seeds, and yeast.

3. Dead (once living) - This means that the thing is dead right now, but before it died it was alive. For example, a steak. This used to be an animal that was alive.

What is the 1 type of dead things?

Was never and will never be alive. It doesn’t show all 7 characteristics of life.

What is a prediction?

guessing what the outcome of something is, without a because statement

What is a hypothesis?

A proposed explanation for a set of observations (or an observed phenomenon). This leads to predictions that can be tested through experimentation.

What is a fact?

Observations of the world around us

What is a law?

A statement that DESCRIBES a phenomenon of nature (the “what”)

What is a theory?

A well substantiated (support) explanation acquired through the scientific method and repeatedly tested and confirmed through observation and experimentation. (the “why” of a natural phenomenon). It is broader than a hypothesis but its an attempt to explain the law. Yet to be refuted.

What is data?

recorded observations

Qualitative data

recorded descriptions. Use adjectives.

Quantitative data

Numerical measurements, statistics

Experiment

a scientific test often carried out under controlled conditions

Independent variable

the factor that is manipulated by the researchers to observe its affects on the dependent variable

Dependent variable

The measure used to judge the outcome of the experiment. This depends on or is affected by the manipulated variable

Controlled experiment

an experiment group is compared with a control group. These groups differ in only one variable the experiment is designed to test.

Constants

variables in an experiment that need to stay the same in order for the experiment to be done properly and they are kept the same to make sure you are only testing the independent variable.

What are the 10 levels of organization?

cell, tissue, organ, Organ system, organism, population, community, ecosystem, biome, biosphere

What are the small 3 levels of organization before cell?

atom, molecule, organelle

1st level - Cell

Is the basic unit of life and living. Anything alive has to have one or more cells.

2nd level - Tissue

When there are a lot of cells working together for a combined function.

3rd level - Organ

a structure made up of many tissues that perform a specific function

4th level - Organ System

Multiple organs working together in a body to perform complex functions necessary for the organism's survival.

5th level - Organism

an individual (like a human)

6th level - Population

When there are multiple organisms of the same species that can breed with each other.

7th level - Community

When you have populations of different species together (doesn't include abiotic factors)

Abiotic

non living

Biotic

living

8th level - Ecosystem

When abiotic factors are considered in the community with the biotic factors. Refers to interaction with the environment, which is why they can be found in different regions of the world.

9th level - Biome

ecosystems in regions collectively (ex. desert, rainforest)

10th level - Biosphere

all of the biomes put together. Global sum of ecosystems

What is a single celled organism or unicellular organism?

An “organism” that is made up of one cell. This is not technically an organism because to be an organism you need multiple cells, to make tissues, then organs, and then organs systems. But you can;t do that with only one cell.

What is the highest level of organization of a single celled organism?

Cell

What is a multicellular organism?

An organism with more than one cells. The highest level can’t be determined because it depends on the organism. It can be tissue, or organs, or organs system. But technically it is an organism.

What are the 4 types of tissues?

Nervous, Muscle, Connective (bone), and Epithelial (skin)

Single celled organisms

1 cell in total, can do ALL tasks to survive (7 characteristics of life), can live on their own, but they can only be so big. They are limited in size because they are only one cell. Examples: Paramecium, Chalmondomes, Bacteria

Colony

Are single celled, BUT they live in groups. Each cell can do all the tasks it needs to survive. They have the advantage of protection, strength, and stability. They can grow in size/unit. Examples: Dental plaque

Multi celled organisms

many cells, 2 or more. Each cell is specialized to have a specific function which makes it more efficient, and allows more complex and larger sizes. This is also called Division of labor. BUT it relies on other cells, and 1 cell can’t live on its own, because it can only perform its specialized task. Example: Volvox, Hydra, Plants, Animals

Division of Labor

A biological concept where cells or organisms specialize in specific functions, increasing efficiency and allowing for more complex structures. This specialization is essential in multi-celled organisms, as each cell relies on others to maintain overall function.

Homeostasis

state of balance in body. Ability to regulate internal conditions despite external environment and factors.

Endotherm

“warm blooded” body keeps the same temperature despite outside conditions. (example of negative feedback)

Ectotherm

“cold blooded” body temperatures that fluctuate with the environment. These organisms rely on external sources for temperature regulation.

Negative Feedback

When a variable triggers a counteracting response to come back to a set point (homeostasis) (ex. hot = sweating and vasodilation, cold = shivering and vasoconstriction)

Positive Feedback

instead of counteracting the variable you intensify it until the end goal is reached or the outcome is achieved. (ex. Birth of baby)

What are the 4 parts of a feedback loop?

Stimulus, Sensor, Control, Effector

Stimulus

external factors that trigger the response of the body

Sensors

when nerve cells send signals to the control center (brain)

Control Center

Your brain or other body part processing info given by the sensors.

Effector

the response triggered by a stimulus. It either intensifies or opposes the stimulus.

Thermoregulation

The process by which the body maintains its internal temperature within a certain range despite external temperature changes.

Describe thermoregulation when the temperature is too high

The blood in the body is higher than the set point, so this activates the heat loss center in the hypothalamus (brain). This ten triggers the effectors. Some of the responses are sweating: sweat glands activate secrete perspiration, which then evaporates and cools the body. Vasodilation: blood vessels dilate and allows more blood to the skin’s surface (making your skin red) with helps the heat escape.

Describe thermoregulation when the temperature is too low

The blood temperature is lower than the set point which activates the heat generating center in the hypothalamus (brain). This triggers the control center to start the effectors which are shivering: when skeletal muscles activate and contract creating kinetic energy, which produces heat. Vasoconstriction: blood vessels constrict and the blood is moved closer to the core and deep tissue, (most important parts) and this gets it farther from the skin surface, preventing heat loss. Goosebumps: small muscle contractions at the hair follicles that create an insulating layer of air. They trap heat with them and help maintain body temperature.

Glucoregulation

The process by which the body regulates blood glucose levels to maintain energy homeostasis, involving hormones like insulin and glucagon.

Hyperglycemia

when there is too much glucose in the bloodstream

Hypoglycemia

when there is too little glucose in the bloodstream

Explain glucoregulation when there is too much glucose

The stimulus is usually eating a meal, but when the blood sugar levels increase the pancreas senses it and activates the effectors which is insulin. Insulin is released into the bloodstream to bring the glucose into the cells.

Explain glucoregulation when there is not enough glucose

The stimulus is usually being hungry. Then the pancreas senses the lack of glucose and low blood sugar levels, and triggers the effector. The effector is glucagon. This hormone breaks the stored glycogen chains and brings them back into the cells and bloodstream to raise the blood sugar levels.

Glycogen

a bunch of glucose put together in a chain. It is usually the extra glucose that isn’t needed, and is stored in the liver for later.

What 2 hormones does the pancreas secrete?

Insulin and Glucagon

Insulin

when there is too much glucose it brings it into cells

Glucagon

When the body needs more glucose, it breaks the glycogen chain down into glucose and releases it into the bloodstream and cells

Respiration Regulation

The body monitoring CO2, pH of blood, and regulating breathing.

What happens when the CO2 increases?

The blood pH decreases, making it more acidic. The brain senses the high levels of CO2 when you inhale/hold breath (specifically the medulla), and it tells you to exhale which releases all of the CO2 and restores normal pH levels.

what happens when the CO2 decreases?

the blood pH increases making it less acidic. The brain (medulla) senses the low levels of CO2 when you are breathing quickly (hyperventilating) and it tells you to breathe slower and deeper. so you can inhale more. This allows for the CO2 levels to build back up and restores the pH levels.

What is physiology?

study of organisms