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7.9 Phylogeny

2 min readjanuary 4, 2023

Samantha Himegarner

Samantha Himegarner

Jillian Holbrook

Jillian Holbrook

Samantha Himegarner

Samantha Himegarner

Jillian Holbrook

Jillian Holbrook

Phylogenetic Trees

offer a visual representation of , and can even offer a by showing the amount of change in organisms over time. This type of diagram shows through distance, as organisms more closely related are located near each other and less closely related organisms are further apart.

More than that, show the gained or lost by species over time. By doing this, are a fundamental tool in to understand the relationships between different species, examine linked , and study the evolution of different characteristics and . 🧬🌳

Cladograms

and both show relationships between , but show the amount of change over time, which is calibrated by or a . are present in more than one lineage. are inherited from common ancestors. Comparing these characteristics of species informs the construction of evolutionary diagrams.

typically focus on morphological (visible trait) similarities between species, such as beak type, meaning can be hypothesized with reasonable differences. However, molecular data, like DNA and/or , in often provide more accurate and reliable evidence than morphological . 🦜

https://firebasestorage.googleapis.com/v0/b/fiveable-92889.appspot.com/o/images%2FScreen%20Shot%202020-04-04%20at%206.21.10%20PM.png?alt=media&token=42476f58-fda7-43d6-91a6-2682bf9018ab

A cladogram is shown to the left, and a phylogenetic tree is pictured to the right. Image courtesy of WikiMedia Commons.

Speciation

Still, and both still illustrate common ancestry and .

is the process by which new species are formed. It occurs when a group of organisms becomes isolated from the rest of their population and evolves into a separate species over time through a variety of mechanisms, including , , or .

, or the points in which two species diverge/speciate, help point out the most recent of different species, which perhaps shows a trait that was shared, gained, or lost. The “” represents the lineage or species that is the least closely related to the rest of the organisms shown. 🐆

It is important to remember that and represent hypotheses, which means that they are constantly being revised based on new scientific evidence. This tool enables us to make predictions, but they do not perfectly model all .

Key Terms to Review (21)

Timeline of Evolution

: The timeline of evolution refers to the chronological sequence of events since life began on Earth, including when different groups of organisms evolved.

Phylogenetic Trees

: A phylogenetic tree is a diagram that represents the evolutionary relationships among various species or other entities that are believed to have a common ancestor.

Evolutionary Relationships

: Evolutionary relationships refer to how closely related different species are in terms of their evolution. This is often determined by comparing physical and genetic characteristics.

Evolutionary Biology

: Evolutionary biology is the study of the origin and descent of species over time, as well as their change over time.

Cladograms

: A cladogram is a diagram used in cladistics which shows relations among organisms based on shared derived characteristics that can be traced back to a group's most recent common ancestor.

Traits

: Traits are distinguishing characteristics or qualities that are inherited, such as eye color, height, and skin color in humans.

Lineages

: Lineages are sequences of species, each one giving rise to the next, that represent a line of evolutionary descent.

Fossils

: Fossils are preserved remains or traces of animals, plants, and other organisms from the past.

Molecular Clock

: A molecular clock uses mutation rates in DNA sequences to estimate when two types of organisms diverged in evolution.

Derived Traits

: Derived traits are newly evolved features that did not appear in the ancestors of a lineage.

Morphological Similarities

: Morphological similarities refer to physical traits that different organisms share due to either common ancestry (homology) or convergent evolution (analogy).

Shared Characteristics

: Shared characteristics are traits that two or more species have in common, often due to a shared ancestor.

Speciation

: Speciation is the process by which new distinct species evolve from pre-existing ones over time due to genetic divergence often caused by geographic isolation or different selection pressures.

Protein Sequence Similarities

: Protein sequence similarities refer to the degree of identity in the sequence of amino acids that make up proteins between different species. This can also indicate genetic relatedness and evolutionary relationships.

DNA Sequence Similarities

: DNA sequence similarities refer to the degree of identity in the sequence of nucleotides between different species. It is used as a measure of genetic relatedness and evolutionary relationships.

Reproductive Isolation

: Reproductive isolation is a mechanism that keeps species from mating with others. It can be caused by differences in mating seasons or mating rituals among different species.

Ecological Isolation

: Ecological isolation occurs when species do not mate because their habitats are different (even though those habitats may be close together).

Geographical Isolation

: Geographical isolation is a term that refers to a group of animals, plants, or other organisms that are separated from exchanging genetic material with others of the same species. This can be due to physical barriers such as mountains, rivers, or vast distances.

Common Ancestor

: A common ancestor refers to an individual organism or species from which two or more descendant species evolved.

Nodes

: In phylogenetics, nodes are points on a tree where a lineage splits into two or more separate lineages. They represent the most recent common ancestor of the lineages that branch from them.

Out-group

: In phylogenetics, an out-group is a species or group of species that is closely related to but not part of the group being studied. It serves as a reference point for determining evolutionary relationships within the group under study.

7.9 Phylogeny

2 min readjanuary 4, 2023

Samantha Himegarner

Samantha Himegarner

Jillian Holbrook

Jillian Holbrook

Samantha Himegarner

Samantha Himegarner

Jillian Holbrook

Jillian Holbrook

Phylogenetic Trees

offer a visual representation of , and can even offer a by showing the amount of change in organisms over time. This type of diagram shows through distance, as organisms more closely related are located near each other and less closely related organisms are further apart.

More than that, show the gained or lost by species over time. By doing this, are a fundamental tool in to understand the relationships between different species, examine linked , and study the evolution of different characteristics and . 🧬🌳

Cladograms

and both show relationships between , but show the amount of change over time, which is calibrated by or a . are present in more than one lineage. are inherited from common ancestors. Comparing these characteristics of species informs the construction of evolutionary diagrams.

typically focus on morphological (visible trait) similarities between species, such as beak type, meaning can be hypothesized with reasonable differences. However, molecular data, like DNA and/or , in often provide more accurate and reliable evidence than morphological . 🦜

https://firebasestorage.googleapis.com/v0/b/fiveable-92889.appspot.com/o/images%2FScreen%20Shot%202020-04-04%20at%206.21.10%20PM.png?alt=media&token=42476f58-fda7-43d6-91a6-2682bf9018ab

A cladogram is shown to the left, and a phylogenetic tree is pictured to the right. Image courtesy of WikiMedia Commons.

Speciation

Still, and both still illustrate common ancestry and .

is the process by which new species are formed. It occurs when a group of organisms becomes isolated from the rest of their population and evolves into a separate species over time through a variety of mechanisms, including , , or .

, or the points in which two species diverge/speciate, help point out the most recent of different species, which perhaps shows a trait that was shared, gained, or lost. The “” represents the lineage or species that is the least closely related to the rest of the organisms shown. 🐆

It is important to remember that and represent hypotheses, which means that they are constantly being revised based on new scientific evidence. This tool enables us to make predictions, but they do not perfectly model all .

Key Terms to Review (21)

Timeline of Evolution

: The timeline of evolution refers to the chronological sequence of events since life began on Earth, including when different groups of organisms evolved.

Phylogenetic Trees

: A phylogenetic tree is a diagram that represents the evolutionary relationships among various species or other entities that are believed to have a common ancestor.

Evolutionary Relationships

: Evolutionary relationships refer to how closely related different species are in terms of their evolution. This is often determined by comparing physical and genetic characteristics.

Evolutionary Biology

: Evolutionary biology is the study of the origin and descent of species over time, as well as their change over time.

Cladograms

: A cladogram is a diagram used in cladistics which shows relations among organisms based on shared derived characteristics that can be traced back to a group's most recent common ancestor.

Traits

: Traits are distinguishing characteristics or qualities that are inherited, such as eye color, height, and skin color in humans.

Lineages

: Lineages are sequences of species, each one giving rise to the next, that represent a line of evolutionary descent.

Fossils

: Fossils are preserved remains or traces of animals, plants, and other organisms from the past.

Molecular Clock

: A molecular clock uses mutation rates in DNA sequences to estimate when two types of organisms diverged in evolution.

Derived Traits

: Derived traits are newly evolved features that did not appear in the ancestors of a lineage.

Morphological Similarities

: Morphological similarities refer to physical traits that different organisms share due to either common ancestry (homology) or convergent evolution (analogy).

Shared Characteristics

: Shared characteristics are traits that two or more species have in common, often due to a shared ancestor.

Speciation

: Speciation is the process by which new distinct species evolve from pre-existing ones over time due to genetic divergence often caused by geographic isolation or different selection pressures.

Protein Sequence Similarities

: Protein sequence similarities refer to the degree of identity in the sequence of amino acids that make up proteins between different species. This can also indicate genetic relatedness and evolutionary relationships.

DNA Sequence Similarities

: DNA sequence similarities refer to the degree of identity in the sequence of nucleotides between different species. It is used as a measure of genetic relatedness and evolutionary relationships.

Reproductive Isolation

: Reproductive isolation is a mechanism that keeps species from mating with others. It can be caused by differences in mating seasons or mating rituals among different species.

Ecological Isolation

: Ecological isolation occurs when species do not mate because their habitats are different (even though those habitats may be close together).

Geographical Isolation

: Geographical isolation is a term that refers to a group of animals, plants, or other organisms that are separated from exchanging genetic material with others of the same species. This can be due to physical barriers such as mountains, rivers, or vast distances.

Common Ancestor

: A common ancestor refers to an individual organism or species from which two or more descendant species evolved.

Nodes

: In phylogenetics, nodes are points on a tree where a lineage splits into two or more separate lineages. They represent the most recent common ancestor of the lineages that branch from them.

Out-group

: In phylogenetics, an out-group is a species or group of species that is closely related to but not part of the group being studied. It serves as a reference point for determining evolutionary relationships within the group under study.