Unit 1: Living Systems Biology is the study of life

Bio = life Logy = study of

The scientific study of all forms of life, or all types of organisms

Science means “to know”

Science is a body of knowledge about the natural world

In class Activity = lets propose an explanation for why it rains without including any scientific

thinking.

Clouds are raining

Invisible rivers are crying

Rain god pours water on earth when angry

Suppose someone doesn’t believe your explanation, could you supply evidence to

support your explanation? No…why not…can’t gather evidence

Several features of science

Science deals only with the natural world

Scientists collect and organize information in a careful orderly way looking for

patterns and connections between events

Scientists propose explanations that can be tested by examining evidence

Some explanations can be pseudoscience = fall outside the realm of scientific explanation, ex is

astrology

Section 1: Life in Earth Systems

EVIDENCE 1 – Make a claim about what defines a living system.

Humans have used technology since early times. Technology includes even simple things such

as a fork or a pen. Technology is any tool, process, or system that is designed to solve a problem.

If we are to compare a robot to a human we can say that they have a control center to guide

their actions. They are both systems that can perform many of the same tasks.

EVIDENCE 2 – Imagine a company that sells robots like the one shown in figure1 on page 4.

The company makes the claim “This living machine is the perfect companion.” Make a case to

either support or refute this claim. How similar are living and nonliving systems?

Systems and System Models

One approach to understanding natural phenomena is called systems thinking.

This way of thinking looks for links and interactions between the parts of a system to

understand how the overall system works.

Properties of Systems

System – a set of interacting components that work together.

1. Boundaries and Components

Boundaries define the space of the system to separate that system from the rest

of the universe.

Components are all the parts of the system that interact to help the system carry

out specific functions.

Any boundary can be assigned to a system. The boundary that is used for a model does not

necessarily have to correspond to a physical boundary. For example, the Earth. You could use

the Earth’s surface or Earth’s atmosphere as its boundary.

2. Inputs and Outputs

Outputs are generated when the inputs are processed in some ways.

EVIDENCE 3: what is the boundary of the human body? What is the boundary of a robot?

Compare the inputs and outputs of humans and robots in terms of matter and energy.

3. Open and Closed Systems

Systems can be categorized according to the flow of inputs and outputs.

In an open system, the inputs and outputs flow into and out of the system.

In a closed system, the flow of one or more inputs and outputs is limited in some

way.

An isolated system, all of the inputs and outputs are contained within the system.

EVIDENCE 4: Is the human body an open, closed, or isolated system? What about a robot?

Explain your answers.

4. Controls

These help keep the system working properly by monitoring and managing the

inputs and outputs.

Controls can be manual, automatic, or a combination

Feedback is information from one step of a cycle that acts to change the behavior

of a previous step of a cycle.

Feedback is output that becomes input

A feedback loop is formed when an output returns to become an input in the

same system that generated the output.

An example is a thermostat. You input a temperature into the

thermostat. The temperature starts to decrease and the thermostat senses

a changes so it switches on. The temperature will increase until the target

temperature is reached. Once reached it shuts off. It stays off until it

detects a decrease. This is an example of a feedback loop because it is all

within one system.

An example of something that you think a feedback loop would be is

a hummingbird taking the nectar from a flower. The nectar is the output of

a flower and input for the hummingbird. The energy given to the bird from

the nectar allows the bird to continue taking nectar. This however is NOT a

feedback loop because it is between two systems.

System Organization

Systems can range in size and in complexity. The more complex the system the more levels of

organization make it up.

EVIDENCE 5: How do your interactions with nonliving systems affect your environment?

System Models

Model – a pattern, plan, representation, or description designed to show the structure or

workings of an object, system, or concept.

Examples of models are computer simulations, conceptual diagrams such as flow

charts, mathematical equations, physical models

Systems Biology

Systems thinking applied to Biology allows scientists to consider biological phenomena at

different scales and examine how the components of a biological system.

Emergent property – a property that a system has but that its components do not have

Example is a cell. Cells are self-contained systems that can function

independently. When cells are combined with other similar cells they form tissues

and perform unique functions that the individual cell could not do.

The Earth System

The Earth System is all of the matter, energy and processes within Earth’s boundary.

Matter stays within the Earths system, but energy enters the system in the form of sunlight

and exits in the form of heat. Within the system, light energy is converted into other forms of

energy that drive transformations of matter from one form to another as it cycles through the

system.

EVIDENCE 6: Is Earth an open, closed, or isolated system?

Organization of the Earth System

The Earth System is divided into four interconnected systems, or spheres

1. Geosphere – all the solid features of Earth’s surface, such as mountains, continents, and

the sea floor. It also contains everything below the Earth’s surface

2. Hydrosphere – all of Earth’s water, including water in the form of liquid water, ice, and

water vapor.

3. Biosphere – the area of Earth where life exists.

4. Atmosphere – all of the air that envelops Earth’s solid and liquid surface.

EVIDENCE 7: The model shown in figure 9 on page 13 shows the biosphere in the middle of the

diagram with arrows connecting it to the other spheres. Why is the biosphere depicted this

way?

Organization of the Biosphere

All living things and all the places they are found on Earth make up the biosphere. Every part of

the biosphere is connected with every other part.

Hierarchy of Life

Across the biosphere, the variety of life is called biological diversity or biodiversity. It generally

increases from poles to the equator which means greater biodiversity is found in warmer

areas. This is because more living things can survive in warmer temperatures and less

temperature changes during the year.

Factors in an ecosystem

Biotic Factors - The living components in an ecosystem

Animals and plants

Abiotic Factors – the nonliving components in and ecosystem

Rocks and soil

The biotic and abiotic factors in an ecosystem interact and are interdependent

EVIDENCE 8: Using figure 11 on page 11 identify the biotic and abiotic factors. Made a model

to illustrate how these factors interact in this ecosystem.

Characteristics of Living Things

Remember that an Organism = ANY individual living thing

All living organisms must have all 7 of the above characteristics or they will not survive.

1. Cellular structure and function

All living things are made up of one or more cells

The cell is the smallest unit capable of life

Our bodies have 100 trillion cells, a paramecium has one cell

2. Reproduction

It is the a process by which organisms make more of their own kind from one

generation to the next

The rate of reproduction changes based on organism; some bacteria reproduce every

15 minutes but the bristle cone pine tree reproduces after every 5000 years.

Remember that just because an individual can’t reproduce it doesn’t mean a species

won’t survive. (species wouldn’t survive if all organisms couldn’t reproduce)

3. Metabolism

The sum of all chemical reactions carried out by an organism

4. Homeostasis

A constant stable internal condition despite the external environment.

If an organism is unable to balance the internal and external conditions then it will

die.

5. Heredity

The passing of traits to their offspring through genes from parent to offspring.

6. Evolution

A change in inherited characteristics of species over generations

7. Interdependence

Organisms are dependent on one another and their environment.

EVIDENCE 9: Describe at least two biological systems. Explain how these systems are

independent and interconnected with each other.

EVIDENCE 10: Record evidence for whether the robot at the beginning of this lesson meets the

criteria for a living system. Which criteria does it meet, and which does it not? Does a robot

have emergent properties? Explain your answer.