The scientific name of organisms consist of two parts, wherein both parts use a Latin name. The first part identifies the genus, whereas the second part determines the species within the genus.

b. two

The Linnaean classification system, which is arranged from the most specific to most general, starts with the species, genus, family, order, class, phylum, and kingdom.

The Bactrian camel, dromedary, llama, and giraffe belong to the order Artiodactyla, while the platypus belongs to the order Monotremata. These animals belong to the class Mammalia. On the other hand, coral snakes belong to the class Reptilia. Both mammals and reptiles belong to the same phylum Chordata. On the contrary, a sea star is an invertebrate that belongs to class Asteroidea and phylum Echinodermata.

In this case, all of these animals belong to different phyla and the other succeeding taxonomic ranks. However, they all belong to the same kingdom, which is called Animalia.

d. kingdom

The Linnaean classification system identifies and organizes all the organisms based on their observable features, particularly the similarities and differences among them. On the other hand, the modern system of classification does not only study the observable features but it also traces the evolutionary line and relationships between organisms to classify them into larger categories or clades.

Biologists found out that the old Kingdom Monera consists of two different kinds of bacteria. As a result, they reclassified this kingdom into two new kingdoms, which are the Kingdom Eubacteria and Kingdom Archaebacteria.

In classifying living things, scientists grouped the organisms into three domains, which are the Bacteria, the Archaea, and the Eukarya. The first two domains contain single-celled prokaryotes. On the other hand, all eukaryotes are placed under the domain Eukarya.

All eukaryotes are placed under the domain Eukarya. These eukaryotes are found in four kingdoms, which include the kingdoms of Protista, Fungi, Plantae, and Animalia.

Picture A shows a flowering plant. It belongs to Kingdom Plantae.
Picture B shows a paramecium. It belongs to Kingdom Protista.
Picture C shows a mushroom. It belongs to Kingdom Fungi.
Picture D shows a fish. It belongs to Kingdom Animalia.

A clade is defined as the group of species that evolved from a single common ancestor and its descendants. A clade is usually illustrated in a cladogram, which is a drawing that shows all the evolutionary relationships among species. It also shows how evolutionary lineages split from common ancestors.

a. clade

Organisms that belong to domain Archaea are known to be extremophiles, which live in extreme or harsh environments. Archaea were usually seen in hot springs and salt lakes. Members of this domain include methanogens and halophiles.

a. Archaea

The domain Archaea and the domain Bacteria contain single-celled prokaryotes. On the other hand, all eukaryotes are placed under the domain Eukarya. In this case, the main difference between the prokaryotes and eukaryotes is the presence of membrane-bound organelles, such as the nucleus, in eukaryotes. Prokaryotes do not contain a nucleus.

d. nucleus

The lines in the diagram represent the evolutionary lines between the common ancestor and its descendants in numbers 1, 2, 3, and 4.

The point where the two lines intersect is called a node. It represents the last point in which two groups of organisms shared the same ancestor.

The derived character in organisms reveals the trait that was passed on from the common ancestor to its descendants. Scientists look for this trait in order to properly classify or group organisms into the right clade. An example of a derived character is the four limbs, which are seen in all the members of superclass Tetrapoda. This trait is inherited from a common ancestor that has four limbs.

Since mitochondrial DNA can be inherited from the parent into its offspring, it can be used as a derived character. This is the reason why scientists use DNA sequences in classification by comparing the genetic information between two species. If the DNA of two species are more similar or homologous, they recently shared a common ancestor; hence, they are more closely related.

The tree of life shows the connection that exists between living things. It illustrates the evolutionary relationships among the major groups of organisms that are included in the three domains of life. The concept of Charles Darwin regarding the descent with modification was the core of this classification. This structure does not only show hypotheses on how modern organisms have evolved over time but it is also a great reminder that life is a natural process that is always changing.

Aside from not being considered as a formal taxon, the Kingdom Protista is not a true clade because it does not form any monophyletic group. The unicellular eukaryotes in this group are not considered as animals, plants, or a fungi. In this case, they do not have a single common ancestor.

Aside from not being considered as a formal taxon, the Kingdom Protista is not a true clade because it does not form any monophyletic group. The unicellular eukaryotes in this group are not considered as animals, plants, or fungi. In this case, they do not have a single common ancestor.

The term phylogeny, which is also known as the tree of life, refers to the study of evolutionary relationships that exist among life-forms. It focuses on genetics and morphology to make evolutionary connections between organisms.

The derived character in organisms reveals the trait that was passed on from the most recent common ancestor to its descendants. Unlike the presence of a shared trait in several groups or lineages, the presence of a derived character sets the members of a clade apart from the older groups.

Members of domains Bacteria and Archaea are single-celled prokaryotes. These organisms obtain energy using photosynthesis, chemosynthesis, and consuming other organisms. However, the members of domain Bacteria have cell walls that contain peptidoglycan, whereas members of the domain Archaea do not have peptidoglycan on their cell walls. Moreover, they are known to live in extreme or harsh environments.

To determine if the tube-shaped and limbless bodies of snakes and worms are derived traits, their DNA can be compared. The similarities and differences in their genes can show if the two species are either closely or distantly related.

Linnaeus would probably ask and look for similarities and differences between organisms to determine whether they are related or not. On the other hand, a modern taxonomist would ask questions that would determine the evolutionary descent of organisms to trace their connection to a common ancestor. In this way, they can be grouped into larger categories or clades.

Classifying organisms according to their overall physical or behavioral similarities can be quite misleading. For example, a dolphin resembles a fish but it is not a fish. A dolphin belongs to the class Mammalia. Unlike dolphins, most fishes are not warmblooded and they do not produce milk.

In this case, studying the evolutionary relationships and patterns between organisms will not just allow us to understand how living and extinct species are related because of a common ancestor. It would also help overcome misconceptions and determine how species are closely related in order to group them properly.

The term domain refers to a larger taxonomic category than a kingdom. It was added by the scientists to reflect the differences between the two groups of bacteria that are single-celled prokaryotes: Bacteria and Archaea.

The wings of the birds and the bats are considered as analogous structures, which share the same function. However, their wings were not inherited from a common ancestor that has wings but they got it from an ancestor that has four limbs; hence, the limbs can represent the last point in which birds and bats shared a recent single common ancestor.

Moreover, the limbs of birds and bats are actually homologous to each other. Birds and bats usually have the same embryonic tissues during its development stage due to the same evolutionary origin. However, when these animals start to mature, their structures appeared differently due to some modifications. Bats have flaps of skin in their fingers and arms, whereas the birds contain feathers that extend in their arm.

The wings of the birds and the bats are considered as analogous structures, which share the same function. However, their wings were not inherited from a common ancestor that has wings but they got it from an ancestor that has four limbs; hence, the limbs can represent the last point in which birds and bats shared a recent single common ancestor. Therefore, the answer is yes. Birds and bats are related by a common ancestor that has limbs.

The Kingdom Protista is not a true clade because it does not form any monophyletic group. The unicellular eukaryotes in this group are not counted as animals, plants, or fungi. In this case, they do not have a single common ancestor.

Here are some questions which can help us classify corals into the proper kingdom:
1. Is it a prokaryote or a eukaryote?
2. Is there a cell wall and a nucleus in the organism?
3. Is there a peptidoglycan or chitin in its cell wall?
4. Is it a heterotroph or an autotroph?

Scientists discovered the fossils of a bird-like dinosaur called Archaeopteryx. This evidence shows us that birds evolved from an ancestor, which is a theropod that has hollow bones and three-toed limbs. In this case, its descendants were able to inherit these derived characteristics. Other inherited characteristics include bipedalism, shortened or reduced forelimbs, and brooding behaviors.

The term phylogeny, which is also known as the tree of life, refers to the study of evolutionary relationships that exist among life-forms. This is similar to how a family tree works because it also focuses on genetics and heredity to make evolutionary connections and patterns. The tree of life and the family tree both trace the relationships between individuals over many generations.

Fishes are considered paraphyletic, which means that they have evolved from a common ancestor but not including all the descendants. Due to this reason, fishes are grouped into several classes and subclasses to reflect the differences between the fish species, such as the structure of their mouths and the type of their skeletons.

According to the diagram, lizards and salamanders evolved from a common ancestor. They all share characteristics that include the presence of a backbone and four limbs.

The order of the five derived characters reflect the evolutionary relationship among vertebrates, wherein the oldest ancestor is situated at the bottom of the diagram, while the youngest ancestor is at the top of the diagram. This also reveals that such traits were passed on from the most recent common ancestor to its descendants.

Moreover, the presence of a derived character sets the members of a clade apart from the older groups. For example, the derived characteristic of a wallaby is the presence of mammary glands, which was inherited from the most recent common ancestor. This trait is what keeps the wallaby different from a lizard and a salamander.

A tuatara is a rare reptile that resembles a large lizard. The derived traits that set it apart from amphibians and fishes include the presence of backbone and four limbs and the absence of amniotic eggs. Therefore, it should fit after the node that says “four limbs.” It is situated between the clades of trout and salamander.

One way to understand the Linnaean classification system is to compare it to a person’s address. The levels of the taxonomic rank and the address go from broad to specific. For example, the kingdom, which is the broadest rank, is compared to a continent. The phylum is compared to a country, whereas the class is like the state. On the other hand, the order is compared to the zip code, the family is like the city. The street is compared to the genus and the house number is like the species.

A cladogram reveals the evolutionary relationship among organisms by showing how they are closely or distantly related to one another. It illustrates how the traits were passed on from the most recent common ancestor to its descendants. Oftentimes, the oldest ancestor is situated at the bottom of the diagram, while the youngest ancestor is at the top of the diagram.

Reptiles are not considered as a true clade because they do not constitute a monophyletic group. Instead, they are under a paraphyletic group that does not include all the descendants of their common ancestor. The common ancestor of reptiles are also the ancestors of mammals. However, mammals are not called reptiles.

According to the graph, the ray-finned fishes, which are members of the bony fishes, and sharks, which are members of the cartilaginous fishes, branched off from a common jawed vertebrate ancestor. Therefore, ray-finned fishes did not evolve from sharks, but they evolved from a jawed vertebrate.

The mammary glands are only found in the clade of mammals; hence, it is the derived character of mammals. This unique trait is what sets the mammals from other species or clades because no other vertebrate species have mammary glands.

According to the table, the characteristic that is shared by most organisms is the vertebrae. All turtles, lampreys, frogs, fishes, and cats have this trait. On the other hand, the characteristic that is shared by the fewest organisms is the hair. The cat is the only animal that possesses this trait.

Using the data from the table, the sequence in which organisms are arranged from the most recently evolved to the most ancient would look like this: cat, turtle, frog, fish, and lamprey.

Using the data from the table, the sequence in which the traits are arranged from the most recently evolved to the most ancient would look like this: hair, amniotic egg, four legs, jaw, and vertebrae.

In this case, the very first characteristic that has evolved first is the vertebrae. All the descendants of the vertebrate ancestor inherited this trait. On the other hand, the characteristic that evolved most recently is the hair. The cat is the only descendant of the ancestor that possessed this trait.

Species A and species C have the least number of differences. These species only have 3 base-pair differences. In addition, species B and species D also have 4 base-pair differences. Their relationships suggest that the organisms (A-C and B-D) with the least number of differences are closely related.

It is possible that the two most recent evolutionary events occurred when species C branched out from species A and when species B and species D branched out from a common ancestor.

The cladogram below shows the data that is shown in the table. It illustrates the evolutionary relationships between species A, B, C, D, and E.

The cladogram below shows the data that is shown in the table. It illustrates the evolutionary relationships between species A, B, C, D, and E. (Click to see the diagram)

The differences between the species are strongly supported by the data on the table. This aspect is helpful in determining how much has changed within the species and in comparing the relationship between them based on their differences. However, the data weakly supports the order of evolutionary events. It does not illustrate the similarities or the traits shared between the organisms and their ancestors.

Unlike the traditional classification that focuses on the physical traits of species, the modern taxonomy focuses on the evolutionary connection between species to classify them into clades. A clade is a term that is defined as the group of species that evolved from a single common ancestor and all of its descendants. A clade is usually illustrated in a cladogram, which is a drawing that shows all the evolutionary relationships among species. It also shows how evolutionary lineages split from common ancestors.

Classifying organisms according to their overall physical or behavioral similarities can be quite misleading. In this case, studying the evolutionary relationships and patterns between organisms is more useful because it will not just allow us to understand how life on Earth is connected and how living and extinct species are related because of a common ancestor. It would also help overcome misconceptions and determine how species are closely related in order to group them properly.

In order to determine the relationship between beetles A, B, and C, their DNA sequences can be compared. In this way, scientists can determine the similarities and the mutations in the genes in order to see how the species are closely related to one another. If there are only a few mutations in the genes of two species, this means that they are similar and related. It is likely that they shared a recent common ancestor. On the other hand, if there are many mutations observed in the genes, the species shared an ancestor a long time ago.