Characteristics of Life - Video Tutorials & Practice Problems
On a tight schedule?
Get a 10 bullets summary of the topic
1
concept
Characteristics of Life
Video duration:
6m
Play a video:
Video transcript
In this video we're going to talk about the characteristics of life and so all living organisms regardless if they are unicellular or multicellular organisms share 8 characteristics that distinguish these living organisms from the non living things that surround them and so if we take a look at our table down below, notice we're listing the 8 characteristics that are shared by all living organisms and so we'll go through each one of these 8 characteristics 1 by 1. And so the first characteristic shared by all living organisms is that all living organisms are composed of cells or in other words, all living organisms are cellular. Now, recall from some of our previous lesson videos that we define cells as the smallest or the most basic fundamental unit of life. Meaning that nothing smaller than the cell displays all of the characteristics of life and so nothing smaller than the cell is considered alive. Now, notice over here we're showing you an image that is showing you cells. And once again as we move forward in our course we're going to talk a lot more about the structure and function of different types of cells. But for now, you should just know that all living organisms are composed of cells. Now, the second characteristic that all living organisms share is that all living organisms are organized and this organization allows all living organisms to use smaller structures in order to build larger, more complex structures. And, those larger, more complex structures allow these living, organisms to survive. And so, just like over here in this image, this large brick wall is being built by using smaller individual bricks that are organized in a very specific way. All living organisms are also going to be organized. Now, later in our course we're going to talk about the organizational hierarchy of life, which talks about how, living things are organized on our planet. And now, the third characteristic that's shared by all living organisms is that all living organisms are able to respond to environmental stimuli or in other words, all living organisms are able to respond to changes in the environment. And of course, the environment is constantly changing. And so, for example, over here on the right, we're showing you a plant that is growing on the windowsill and notice that the plant is growing towards the window where the sunlight is shining through. And so this plant is responding to the environmental stimuli which is the sunlight and it is growing towards the sunlight, and so all living organisms are able to respond to environmental stimuli in one way or another. Now the 4th characteristic that's shared by all living organisms is the ability to maintain what is known as homeostasis. And so this is referring to the ability for all living organisms to stabilize or maintain suitable living conditions. And so, not only are all living organisms capable of responding to the environmental stimuli, but they're capable of responding to the stimuli in such a way that it allows them to stabilize or maintain suitable living conditions. And so what's important to keep in mind here is that the environment that is surrounding living organisms is constantly changing. Think about it. Some days when we go outside it's super hot outside and other days when we go outside it's really really wet or really really cold And so, the environment is constantly changing and that environment that's changing may not be the best environment for living organisms. And so, living organisms have to be able to respond to the changing environments in such a way that it allows them to maintain suitable living conditions. And so a classic example of of maintaining homeostasis is when the human body sweats and so in really really hot environments like on a hot summer day, your body will start to sweat in order to cool off and maintain living conditions. Because if your body gets too hot then you will not be able to survive, and so sweating helps to cool off your body and allows your body to maintain more suitable living conditions, and once again all living organisms are capable of maintaining homeostasis. Now, the 5th characteristic that's shared by all living organisms is the ability to reproduce. And so, reproduce or reproduction refers to the capacity to produce life or the ability to produce more life, and reproduction can either occur sexually or it can occur asexually. Now, sexually of course means that there are going to be 2 parents involved in the reproduction and asexually means that there will only be 1 parent involved in the reproduction. And, we'll get to talk a lot more about the reproduction abilities of living organisms much later in our course when we're talking about mitosis and meiosis. But for now you should just know that all living organisms have the ability to reproduce and create more life. And so over here notice that we're showing you an image of a baby to remind you of this characteristic of reproduction. Now, the 6th characteristic that's shared by all living organisms is the ability for all organisms to acquire and utilize energy from the environment or from the surroundings. And so notice over here we're showing you this kid that is eating this carrot in order to obtain energy from its environment. And so all living organisms have the ability to do this, obtain energy from their environment. Now, the 7th characteristic that's shared by all living organisms is that all living organisms contain genetic information and really this is just hereditary information that can be passed down from 1 generation to the next. And the molecule that serves as the genetic material is going to be DNA. And so DNA is a molecule that we'll get to talk a lot more about later in our course, but it does function as the genetic material of life and it is found in all living organisms. And so, over here we're showing you an image that represents the structure of DNA and once again we'll get to talk a lot more about DNA and genetics as we move forward in our course. But for now note that all living organisms contain genetic information specifically DNA. Now the 8th characteristic and the final characteristic shared by all living organisms is the ability to evolve or evolution. And so, evolution refers to changes in the DNA of a population over really long periods of time and these changes in the DNA in the population over long periods of time allows the population to adapt and improve their survival in their environments. And so evolution is something that occurs in all living organisms and all populations of living organisms. And so we'll get to talk a lot more about evolution later in our course, but notice over here we're showing you a classic image that represents evolution, and how characteristics can be acquired and changed, over time to lead to new species. And so, these are really the eight characteristics of life that are shared by all living organisms. Now it is important to note that viruses such as the coronavirus, for example, are not considered alive and this is because viruses lack, some of the characteristics of life. They do not display all of these characteristics of life. Mainly, the ability to reproduce on their own without having to hijack other cells. Now, we'll get to talk a lot more about viruses later in our course, but for now you should note that viruses are generally not considered alive because they lack some of these characteristics of life. But again, this here concludes our brief lesson on the characteristic of life and all living organisms from single celled bacteria to you and I display these characteristics of life. So we'll be able to get some practice applying these concepts as we move forward so I'll see you all in our next video.
2
example
Characteristics of Life Example 1
Video duration:
2m
Play a video:
Video transcript
Alright. So here we're looking at an example problem that's asking which of the following is not a characteristic of life, And we've got these 4 potential answer options down below. Now because we're looking for the option that is not a characteristic of life, really we're looking for the false answer option because it's gonna be the one that is not a characteristic of life. And so option a says, structure of an organism based on hierarchy of organization. And of course, we know that one of the major characteristics of life is that they have organization, and so option a, to say that the structure of an organism is based on a hierarchy of organization, is actually a true statement, Again, because it's referring to the organization characteristic. And because it is true, it's not the false answer option that we're looking for, so we can eliminate answer option a. Now moving on to option b, it says the ability to establish a constant internal temperature, despite the fact that the temperatures of the environment are constantly changing. And so this is referring to the ability to maintain homeostasis. And we know that maintaining homeostasis is definitely a characteristic of life. So this is once again a true answer option, which means that we can eliminate answer option b because it's not the false answer option that we're looking for. So now we're between either option c or option d, and notice option c says, the ability to convert sunlight energy into chemical energy, whereas d says DNA molecule that stores genetic and hereditary information. Now recall that the hereditary information of using DNA, is a characteristic shared by all living organisms. All living organisms use a DNA molecule as the hereditary molecule for to store hereditary information. And so once again, we're saying that option d here is true, again, because it's referring to hereditary information and DNA. And so we can go ahead and eliminate answer option d because it's not the false answer option that we're looking for. And so this only leaves answer option c here as the false answer option that we're looking for. Now, the ability to convert sunlight into chemical energy is something that some living organisms have, but it is not a characteristic of life shared by all living organisms. And so for that reason, this is actually the false answer option that we were looking for. And so we can go ahead and mark c as the answer that we were looking for, and that concludes this practice or this example. So I'll see you guys in our next practice problem.
3
Problem
Problem
All of the following are characteristics of life EXCEPT:
A
Evolution
B
Multicellularity
C
Homeostasis
D
Reproduction
4
Problem
Problem
Salt concentration in blood remains relatively steady, regardless of a person's diet. This best illustrates: