GESCI 101 Section 4.23

Explore 4.23 The Unity & Diversity of Life

Learning Objectives

By the time you have completed the 4.23. Introduction & Exploration Activities, you should be able to:

Understand the meaning of the following terms/concepts and be able to identify examples of each: diversity of life, unity of life, descendancy, homologous trait, analogous trait, anatomical homology, biochemical homology, embryonic homology, vestigial homology, fossil record. Also, identify characteristics that distinguish living organisms from nonliving things.
Identify characteristics that make humans 1) similar to (unified with) the rest of life (including embryonic, biochemical, anatomical, and vestigial homologies) and 2) different (diverse) from the rest of life. Also, describe the causes of life’s unity (descendancy) and diversity (adaptation/innovation).
Identify characteristics of humans that classify them as animals (kingdom Animalia), vertebrates (subphylum Vertebrata), mammals (class Mammalia), primates (order Primate), hominids, hominins, and Homo sapiens (genus & species)?

Scientific Terms/Concepts

Terms: Diversity of Life, Unity of Life, Descendancy, Homologous Trait, Analogous Trait, Anatomical Homology, Biochemical Homology, Embryonic Homology, Vestigial Homology, Fossil Record.

Define and give an example of each term:

Term:

Diversity of Life

Definition:

Example:

Term:

Unity of Life

Definition:

Example:

Term:

Descendancy

Definition:

Example:

Term:

Homologous Trait

Definition:

Example:

Term:

Analogous Trait

Definition:

Example:

Term:

Anatomical Homology

Definition:

Example:

Term:

Biochemical Homology

Definition:

Example:

Term:

Embryonic Homology

Definition:

Example:

Term:

Vestigial Homology

Definition:

Example:

Term:

Fossil Record

Definition:

Example:

Identify characteristics that distinguish living organisms from nonliving things. Define and give a function of each characteristic:

Term:

DNA

Definition:

Example:

Term:

Cells

Definition:

Example:

Term:

Growth and Development

Definition:

Example:

Term:

Homeostasis

Definition:

Example:

Term:

Environmental Sensitivity

Definition:

Example:

Term:

Metabolism

Definition:

Example:

Term:

Reproduction and Heritability

Definition:

Example:

Term:

Evolution

Definition:

Example:

Human Similarities & Difference from Other Life

Identify characteristics that make humans 1) similar to (unified with) the rest of life (including embryonic, biochemical, anatomical, and vestigial homologies) and 2) different (diverse) from the rest of life. Also, describe the causes of life’s unity (descendancy) and diversity (adaptation/innovation).

What characteristics set you apart from other life forms? Make a list of notable differences below.

Did your list include any of the following: Large powerful brains and associated features like complex emotions, personality, thoughts, beliefs, empathy, culture, & social systems; Fully upright posture; Dexterity of opposable digits & complex tool use; Complex communication including speech, blushing, & immortalized communications; Lack of thick hair & use of clothing; and big babies and associated traits like prolonged postnatal brain growth, long childhoods, & life after children? Some these unique human attributes are illustrated by the images below—of a human brain, nonverbal communication, dexterous use of hands and tools, and person walking.

Large Powerful Brains. Humans have the largest relative brain size of any organism on Earth—by far. And our brains are costly organs: ~30% of the energy your body produces is consumed by your brain! With all this expenditure, it makes sense to use it productively. Good for you for being dedicated to lifelong learning!

Complex Emotions. Although other animals display emotion (particularly in their behavior), the breadth and depth of human emotion is unique. For example, humans are the only known animals to communicate through blushing.

Fully Upright Posture. Although other animals can walk on two legs (briefly), humans are currently the only living species that can walk efficiently on two legs for long periods.

Dexterous Opposable Digits. Although other primates such as apes and chimps have opposable thumbs and can grip item with tremendous power, humans are the only existing species that possesses a ‘precision grip’. These fine motor skills allow humans to hold and manipulate small objects with great precision. For example, we can use a wrench, write with a pen, or type on a keyboard.

Complex Tool Use. Although other animals—such as apes and birds—use tools, only humans plan, design, and build complex tools for specialized purposes. Human tool use is a direct consequence of large, able brains, precision grips, and complex communication.

Complex Communication. All organism—even bacteria—communicate, but human communications are distinctly complex. Humans can communicate incredibly complex ideas, thoughts, and feelings. In addition, humans can use writing and other durable media to communicate across many generations.

Lack of Thick Hair & Use of Clothing. Humans have about as much hair as other mammals, but most of our hair is very fine. In addition to other functions, humans use clothing to provide warmth and protection.

Big Babies with Prolonged Postnatal Brain Growth & Long Childhoods. Humans are born with relatively large heads and take two decades or more—~25% of their lifetimes—to reach maturity. As such, they have abnormally long developmental periods and require tremendous investments from their parents.

Life after Children. Although many males remain fertile throughout their lives, human females spend an unusually long time—again, ~25% of their lives—living after they are fertile. This seems to indicate the importance of social networks—in particular, the importance of females—in helping parents with the duties of unusually prolonged human development. In addition, compared to other animals, it is unusually common for humans to die of old age.

Clearly, humans—like all living organisms—have attributes that make them different from all other living things. Have you ever wondered what causes the diversity exhibited by life? We discuss this below, after exploring the unity of life.

List some features that humans share with chimpanzees?

List some features that humans share with cats, dogs, and horses?

OK, let’s do one more of these. List some features that humans share with snails, insects, starfish, worms, etc.?

Identify the embryo of the mouse, bat, bird (quail), human, dolphin, and cat in the image above.

Living Classifications

Identify characteristics of humans that classify them as animals (kingdom Animalia), vertebrates (subphylum Vertebrata), mammals (class Mammalia), primates (order Primate), hominids, hominins, and Homo sapiens (genus & species)?

List the classification (taxons) to which humans belong, give the characteristic of each taxon, and an example of other organisms in that taxon:

Taxon:

Domain

Characteristics:

Example:

Taxon:

Kingdom

Characteristics:

Example:

Taxon:

Phylum

Characteristics:

Example:

Taxon:

Subphylum

Characteristics:

Example:

Taxon:

Class

Characteristics:

Example:

Taxon:

Order

Characteristics:

Example:

Taxon:

Family

Characteristics:

Example:

Taxon:

Genus

Characteristics:

Example:

Taxon:

Species

Characteristics:

Example:

Is descent through modification the only place we came from?

Though this is a science class, let’s take a step back and consider what we know about the origins of the physical human body from revealed truth. As we consider this topic, it is important to keep in mind what Elder D. Todd Christofferson taught in April 2012 General Conference. He said:

“It should be remembered that not every statement made by a Church leader, past or present, necessarily constitutes doctrine. It is commonly understood in the Church that a statement made by one leader on a single occasion often represents a personal, though well-considered, opinion, not meant to be official or binding for the whole Church.”

And, what Elder Neil L. Andersen taught in October 2012 General Conference as quoted by President Dallin H. Oaks in October 2019 General Conference:

“The doctrine is taught by all 15 members of the First Presidency and Quorum of the Twelve. It is not hidden in an obscure paragraph of one talk.”

Over the years, many Church leaders have shared their personal views or opinions on the question of the origins of the physical human body, but let’s apply what Elders Christofferson, Andersen, & Oaks have taught and apply it to the question of the origins of the physical human body specifically, not the origins of our spirits – which we actually know a lot more about via revelation than we know about the origins of the physical body via revelation.

We know that the creation of the human body was part of the process of the creation of the Earth (Genesis 1: 26-27) and that our bodies are created in God’s image, but the scriptures do not indicate the process by which human bodies were created. The closest description is this: humans were made “from the dust of the Earth” (Genesis 3:19). We also receive information about the origin of humans in the temple. During our temple worship, we review the plan of salvation and the role of the creation. It is interesting to note that during that presentation we are taught that man is first organized and then his spirit is put into his body, thus the body and the spirit are the soul of man. Of course, the body must exist before the spirit can inhabit it, but again, there is no information provided regarding the process by which the physical human body, or the body of any living thing, was formed. The bottom line here is that revelation presents no doctrine regarding the origin of the physical body of humans that requires conflict with what we have discovered by investigating the modern human body and the fossil record. This should not surprise us, because God is the source of truth in scripture and the source of truth in nature. So, we are free to consider what we learn scientifically and how it supplements what we know from revelation. This is one of the great blessings of being a member of a church in which people are encouraged and expected to learn all they can. As President Brigham Young once said, “We should be a people of profound learning pertaining to the things of the world.” (Journal of Discourses 8: 40, 8 April 1860).