Chapter 1- Principles of Life Part I (2023)

Introduction

Video

Alright, let's hop right to it.

Our first chapter is a general introduction into biology, appropriately, titled principles of life.

This PowerPoint will focus on one constitutes life I like the valves and organization among living things.

Biology did not already know is the study of life.

Biologists study all living things from single cell to multi cell organisms.

If it is alive, it falls under the biology umbrella.

All of you things are descended from a common ancestor that only had a single cell characteristic shared by all living.

Things leads to the logical conclusion that all life has a common ancestor.

We will discuss these common characteristics in the next few slides.

What are common characteristics that all living organisms share first all living things are composed of similar structures and similar chemical components, such as cells and proteins living organisms depend on these structures interact in order to maintain life.

These may be chemical pathways or organ systems working together to maintain homeostasis.

Third all living organisms contain genetic information that use a universal code for amino acids, we'll learn more about that later in the semester other common characteristics to all life share are that living organisms must be able to extract energy from the living environment in order to maintain life.

You must be able to replicate their genetic information in the form of DNA and RNA also all life shares structural similarities between genes, for instance, genes that code for pigments and animals also code for pigments in humans.

Also life tends to evolve through gradual changes.

The picture on the right is a picture of the bone Ilona.

You can see how it is different among this group of vertebrates has changed over time to give this organism distinct advantages in differences.

All right, this slide is what I like to call a progress check for in a course of my lectures.

I try to put some questions after the end of a topic.

These questions typically show up on my quizzes or exams in one form or another I tend to ask main ideas with these questions.

So, go ahead and try to answer these I'll give you about a minute or so before we continue to lecture.

Good luck.

All right hope, you're able to answer this progress checks like I said, we'll, see them throughout the course this semester in my lectures.

But before we continue into the history of the first living organisms, the next few slides I want to share this cartoon about viruses virus says to the two cells, you'll, never catch me alive.

First cell says to his buddy, you know, he's right, it's, not technically alive.

What a twist why aren't viruses technically alive think about what characteristics that all life share do viruses share all these characteristics feel free to do a little research on that question.

Also, there are some information your book that can be useful answer this because you'll probably see this question again.

Some later point in the semester, the next few slides are going to discuss the history of early life, how life was able to develop on earth the earth developed about four-and-a-half billion years ago, however, life didn't develop until 600 million years later.

So what change what made the earth? Habitable for life, it's thought that biological molecules rose from random association with chemicals in the environment.

This means that chemicals are able to bump into one another and for more complex chemicals based on their chemistry experiments that simulated conditions on early Earth showed that this was possible.

Nucleic acids were able to be produced in the oceans.

Nucleic acids are important because they can replicate and contain information for proteins.

These proteins are able to participate and facilitate chemical reactions.

This is believed to be the first critical step for life to develop next step that would have had to occur was the formation of a cell membrane biological molecules, such as nucleic acids would have become enclosed within a membrane.

So all membranes are composed of fatty acids, which were found in the early oceans.

These fatty acids would protect the nucleic acids from changes in the water.

The membrane would separate the nucleic acids from the environment.

These would have been the first cells for the next two billion years.

These single-celled organisms were what are called prokaryotes the oceans protected prokaryotes from damaging UV rays.

Since there is little oxygen and no ozone layer within the atmosphere.

So what are prokaryotes prokaryotes are single-cell organisms that do not have a nucleus or membrane-bound.

Organelles bacteria are prokaryotes.

Your DNA is not a nucleus.

We will learn a little bit more about the nucleus in another lecture.

This picture of a prokaryote is surrounded by a membrane, which is labeled inside is de DNA protein and ribosomes prokaryotic cells are less complex than cells that you and I have next next major step for life was the formation of photosynthesis.

Photosynthesis evolved around us.

2.7 billion years ago we will learn about photosynthesis in the later chapter.

However, the short definition of photosynthesis is the utilization of light energy to produce carbohydrates, such as glucose.

This is often done with chlorophyll in plants.

So in short, the energy of sunlight is used to produce biological molecules.

The earliest photosynthetic organisms were similar to cyanobacteria Ostia torria.

What you see in the bottom right here and that you will see in your bio 111 lab is an example of a cyanobacteria.

The reason that photosynthesis is important to early life is that a byproduct is oxygen, which we this is oxygen then began to accumulate within the atmosphere.

These two pictures here are more examples of cyanobacteria.

Same bacteria is in crust in these rocks.

The on these rocks are many, many tiny, single-celled prokaryotic cyanobacteria give these rocks their unique colors.

So why do we care about photos that the assistant history of early life? Well, as it turns out, oxygen was very poisonous to many early prokaryotic organisms.

Some organisms that could tolerate this increase in oxygen were able to evolve aerobic.

Metabolism, aerobic metabolism is more efficient than anaerobic metabolism.

This means that aerobic organisms could produce more energy.

These organisms were able to grow larger and be more successful.

Most organisms today use aerobic metabolism.

Not only did promote aerobic metabolism, but also help develop the ozone layer.

This help to shield UV light from reaching the Earth's surface has helped organisms to move from the oceans to the wind over time.

Some cells are able to develop special membrane, enclosed compartments within them using enclosed.

The compartments are called organelles and allow the cell to perform specialized functions.

One special membrane, closed organelles called the nucleus nucleus contains the cell's genetic information.

These cells that have membrane bound organelles all are called eukaryotes as we mentioned before prokaryotes, lack nuclei and other internal apartments picture on the bottom right is an example of eukaryotic cell with its membrane bound organelles.

So how did these organelles develop? Some researchers think that some organelles developed through endosymbiosis endosymbiosis is one a larger cell and gulf some smaller one for some reason, the cell does not eat the smaller cell because they get some advantage from keeping it.

This is what researchers think is how mitochondria came to be you think that a large you Carrick cell golfed, a small one mitochondria in turn improves energy for the cell.

Likewise, this is what is also believed I'll summon your character eukaryotic organisms are able to photosynthesize is believed that eukaryotic cell and Gulf 2 photosynthetic prokaryotic cell after eukaryotic cells developed multi-celled organisms came about 1 billion years ago for this all living organisms were single sound.

So what led to multicellular organisms failure? Specialization occurred.

This is where a cell becomes specialized perform a specific function.

This could be a cell that has specific enzymes for a particular chemical pathway or cell with a specific structure to aid in feeding, such as cilia or flagella multicellular eukaryotes become bigger and able to adapt to specific environments.

Here is our next progress.

Check.

These two questions are specific to last couple of slides from our PowerPoint.

Go ahead and give them a shot.

Take your time.

Next we're going to talk about how organisms are classified and how they are related.

Each species has a distinct scientific name, also referred to as a by known will name.

This means that there are two parts that are named binomial name is made of the organisms genus and species.

Scientific name must be italicized or underlined when writing or typing it.

The first letter of the genus name is capitalized.

And the species first letter is always lowercase.

Some examples would be Homo Sapien.

Look in the mirror for an example that species another example of vine animal name would be Bo campus erectus or also commonly referred to as the line seahorse and on the bottom right there.

Bottom.

We have what is called die, Toma Bulgari, which is a single-celled algae.

These scientific names show relationships between different species mutations, which is a change in a genome can occur when DNA is replicated.

Some mutations may give rise to structural and functional changes within an organism from this.

A new species may arise on the right are similar, but different species of the ancestor of the horse changes to their DNA have led to the hoof of the horse in a different species than what came before a species evolutionary relationship can be determined by comparing genomes genetic sequencing has also added a molecular evidence to the fossil record.

Thus molecular evidence have allowed scientists who create or called phylogenetic trees.

This type of diagram illustrates an evolutionary relationship among organisms.

This slide here illustrates a genetic tree organisms that are closer together on the tree share more similar DNA than with those that are further apart.

For instance, by looking at this tree, fungi and animals have more similar DNA with one another, and they do with plants.

You can see further way up on the tree here relationships within the tree are based on fossils molecular evidence structural tablet metabolic processes in behavior.

Researchers often look at all this to determine where an organism sits on a phylogenetic tree based on the tree, all organisms that are alive today came from one single common ancestor today.

All living organisms can be grouped into order called domains, neuro 3 of them.

The mains are bacteria, which are the prokaryotes archaea, which is another group of prokaryotes Eukarya, which are eukaryotes because all life is related stuber's discoveries based on one organism can extend to others.

Researchers can use what are called model organisms.

Let me use green algae chlorella to study photosynthesis are we to do this? It could be reason that photosynthesis is the same in plants as it is an algae chlorophyll and algae is same chlorophyll found in trees, flowers, ferns, etc.

These assumptions can be made because all plants and algae are closely related all right here's.

Another progress check, we have four questions this time, let the last few slides sink in.

And when you're ready you're best to answer these questions.

Next we are going to learn about the organization of living things in their need for energy.

Do the physics organize entities tend to lose their organization over time.

They become more disorganized living things require energy in order to combat.

This organization is common in living systems / molecules.

The ecosystems cells require energy to make complex molecules like carbohydrates, nucleic acids, proteins, this organization essential for cells to function within a multicellular organism.

Life is organized by the interactions of autumn's making molecules molecules making cells cells, making tissues tissues, making organs organs making organ systems and organ systems making an organism as you can see from this diagram there's a clear hierarchy of complexity within living organisms.

These organisms interact with their physical environment.

And with each other.

This is one the aspects of ecology.

This can result in a hierarchical structure within the biological world.

A group of similar organisms, make populations different interacting groups of populations, make communities indifferent interacting communities together form an ecosystem.

All these ecosystems interact to form the biosphere.

All these interactions form systems.

A system is a set of interacting parts in which neither the parts nor the whole can be understood without taking into account interactions systems are found at every level of biological organization.

Here's an example, general system.

You have components, a B and C.

You cannot truly understand the system without understanding the interactions of a and B or interactions between B and C.

This slide has three examples of biological systems.

We will look at the first one as an example.

The first component is the amount of free amino acids within a cell.

Second component is the amount of protein T in the cell.

This occurs due to the synthesis of protein T, which would be the interaction next interaction occurs between the amount of protein T in the cell and the amount and breakdown of cell products.

This interaction is to breakdown of T protein to increase the amount of broken down cell products.

Sometimes these concepts of biological systems can be a little confusing for students.

Sometimes it is best to think of these as steps, which they are.

So with a previous example, the first step is the amount of free amino acids, the second step being amount of T protein, this occurred due to this synthesis of T protein.

The third step is the breakdown of cell products to get to this step T protein needs to be breaking down.

One of the takeaway message is from the last few slides is that biological systems are dynamic.

This is due to the flow of energy through them.

They constantly exchange energy with their surroundings.

This can be due through food webs or due to the flow of matter, such as water or nutrients.

This is going to all depend on the amount of sunlight or food that is found within the system.

Alright progress check for this section answer.

These two questions, then head on to part, two of chapter one.

Congratulations on making it through the first of many lectures.

Thank you for listening.