Phylogenetic trees are graphical representations used to illustrate the evolutionary relationships among various biological species or other entities based on similarities and differences in their physical and/or genetic characteristics. These trees are constructed using phylogenetic inference methods that evaluate observed heritable traits, such as DNA sequences or morphology, among species. Here are some key aspects of phylogenetic trees:
Branches and Nodes: In a phylogenetic tree, branches represent evolutionary lineages, and nodes (where branches diverge) represent common ancestors. The length of the branches can indicate the amount of evolutionary change or time.
Root: Most phylogenetic trees are rooted, which means they have a single ancestral lineage (often at the bottom or left of the diagram) from which all organisms represented in the tree descended.
The root represents the most recent common ancestor of all entities on the tree.
Clades: A clade is a group of organisms that includes an ancestor and all its descendants. Clades are identified by finding the most recent common ancestor of the group and tracing all the lineage branches that descend from it.
Monophyletic, Paraphyletic, and Polyphyletic:
Monophyletic groups consist of a common ancestor and all its descendants (a clade).
Paraphyletic groups consist of a common ancestor and some, but not all, of its descendants.
Polyphyletic groups consist of organisms but do not include their most recent common ancestor.
Tree Construction Methods: Phylogenetic trees can be constructed using various methods, such as cladistics, maximum parsimony, maximum likelihood, and Bayesian inference, each of which has its approach to estimating the tree that best represents the evolutionary history among the species.
Molecular vs. Morphological Data: Trees can be built using molecular data (e.g., DNA, RNA, or protein sequences) or morphological data (physical characteristics). Molecular data is often preferred for its abundance and objectivity, but morphological data is crucial for studying fossils and organisms with limited genetic information.
Importance: Phylogenetic trees are fundamental to understanding biodiversity, the process of evolution, and the history of life on Earth. They help scientists classify organisms, trace the transmission of genes and diseases, and infer the evolutionary history of species.
Phylogenetic trees are powerful tools in evolutionary biology, providing insights into the relationships among species, the timing of evolutionary events, and the patterns of descent from common ancestors. Their construction and interpretation are central to studies in taxonomy, systematics, conservation biology, and comparative genomics.
Problem:
By reference to the tree above, which of the following is an accurate statement of relationships?
a) A green alga is more closely related to a red alga than to a moss
b) A green alga is more closely related to a moss than to a red alga
c) A green alga is equally related to a red alga and a moss
d) A green alga is related to a red alga, but is not related to a moss
https://www.youtube.com/watch?v=MhHRS_n_0z8
This is generally true in phylogenetic studies where birds and crocodilians share a more recent common ancestor with each other than either does with lizards. This relationship places birds and crocodiles together in a group known as Archosauria. This reflects the consensus view based on both morphological and genetic studies, indicating that crocodiles are more closely related to birds (both being part of the Archosaur group) than they are to lizards, which are part of a different reptilian lineage.
Problem:
By reference to the tree below, which of the following is an accurate statement of relationships?
A) A crocodile is more closely related to a lizard than to a bird
B) A crocodile is more closely related to a bird than to a lizard
C) A crocodile is equally related to a lizard and a bird
D) A crocodile is related to a lizard, but is not related to a bird
https://www.youtube.com/watch?v=FfU5ioYNN-0
The Most Recent Common Ancestor (MRCA) refers to the most recent individual from which all organisms in a group are directly descended. The concept is used in various fields, including genealogy, evolutionary biology, and phylogenetics, to identify the last common point of origin shared by different species, populations, or individuals within a lineage.
In human genealogy, the MRCA of all currently living humans is sometimes referred to as "Mitochondrial Eve" for matrilineal descent (traced through mitochondrial DNA) and "Y-chromosomal Adam" for patrilineal descent (traced through the Y chromosome). These are not thought to be the first humans, but rather the individuals whose lines of descent have not been broken by extinction or lack of offspring. Estimates suggest that "Mitochondrial Eve" lived roughly 100,000 to 200,000 years ago, while "Y-chromosomal Adam" is estimated to have lived around 200,000 to 300,000 years ago. However, these estimates are subject to change as new evidence emerges.
In evolutionary biology, the MRCA is used to describe the most recent shared ancestor of all members of two species or other taxa. This concept helps scientists understand how species have diverged and evolved from common points in the tree of life.
The search for MRCA involves analyzing genetic markers in present-day organisms to trace back through their evolutionary history. This process helps to reconstruct phylogenetic trees and understand the genetic relationships between species. The concept of MRCA highlights the interconnectedness of all life forms through shared ancestry.
Problem:
Based on the phylogenetic tree below, which two living species are most likely to have similar proteins?
A) B and C
B) A and F
C) F and G
D) E and F
https://www.youtube.com/watch?v=VKDg27lwMvQ
The Most Recent Common Ancestor (MRCA) refers to the most recent individual from which all organisms in a group are directly descended. The concept is used in various fields, including genealogy, evolutionary biology, and phylogenetics, to identify the last common point of origin shared by different species, populations, or individuals within a lineage.
In human genealogy, the MRCA of all currently living humans is sometimes referred to as "Mitochondrial Eve" for matrilineal descent (traced through mitochondrial DNA) and "Y-chromosomal Adam" for patrilineal descent (traced through the Y chromosome). These are not thought to be the first humans, but rather the individuals whose lines of descent have not been broken by extinction or lack of offspring. Estimates suggest that "Mitochondrial Eve" lived roughly 100,000 to 200,000 years ago, while "Y-chromosomal Adam" is estimated to have lived around 200,000 to 300,000 years ago. However, these estimates are subject to change as new evidence emerges.
In evolutionary biology, the MRCA is used to describe the most recent shared ancestor of all members of two species or other taxa. This concept helps scientists understand how species have diverged and evolved from common points in the tree of life.
The search for MRCA involves analyzing genetic markers in present-day organisms to trace back through their evolutionary history. This process helps to reconstruct phylogenetic trees and understand the genetic relationships between species. The concept of MRCA highlights the interconnectedness of all life forms through shared ancestry.
Problem:
What inference can be made from the phylogenetic tree?
A) Species A was probably much larger than any of the other organisms.
B) Species G is extinct.
C) Species C is the most recent common ancestor of species B and D.
D) Species F and G are more closely related than species B and E.
https://www.youtube.com/watch?v=GdcpZ_RVt6s
"Phylogenetic" refers to anything related to phylogenetics, which is the branch of biology that deals with the evolutionary development and diversification of a species or group of organisms. Phylogenetics aims to understand the evolutionary relationships among various species or genes, typically represented in a phylogenetic tree or diagram. A phylogenetic tree is a branching diagram or "tree" showing the inferred evolutionary relationships among various biological species based upon similarities and differences in their physical or genetic characteristics.
The fundamental goal of phylogenetic studies is to reconstruct the lineage of organisms or genes to determine how they are related to one another. This involves:
Identifying the ancestral relationships and descent among species or genes.
Classifying organisms based on their evolutionary history.
Tracing the evolution of specific traits or genes across species over time.
Phylogenetic analyses use various types of data, including morphological (physical characteristics) and molecular (DNA, RNA, or protein sequences), to infer evolutionary relationships. These analyses help scientists understand the biodiversity and the history of life on Earth, contributing to fields such as conservation biology, systematics, and evolutionary biology.
Problem:
The ancestral traits that a taxon retains throughout its evolution are known as what?
A) Homoplasy
B) Apomorphy
C) Plesiomorphy
D) Genetic mutation
Plesiomorphy refers to ancestral traits that a taxon retains throughout its evolution. It represents characteristics that are shared with the common ancestor of a group but may not be unique to that group.
Homoplasy refers to traits that are similar but not derived from a common ancestor.
Apomorphy refers to derived traits that are unique to a particular group.
Genetic mutation is a general term for any change in the DNA sequence.
https://www.youtube.com/watch?v=VLsDDN9Gv-Q
A cladogram's topology refers to the structure or arrangement of its branches that represent the relationships among various organisms based on their shared evolutionary characteristics. Unlike a phylogenetic tree, which often includes branch lengths proportional to genetic change or time, a cladogram primarily
focuses on the order of branching events without necessarily indicating the time scale or genetic distance.
In a cladogram, organisms are placed at the tips of the branches, and each branching point, or node, represents the last common ancestor shared by the organisms branching from that node. The topology of a cladogram illustrates the hypothesized evolutionary pathways between different species or groups, showing how they are related by descent from common ancestors. The arrangement is based on the principle of parsimony, aiming to minimize the number of evolutionary changes needed to explain the observed traits or genetic sequences among the organisms studied.
The topology is critical for understanding evolutionary relationships because it helps scientists infer which traits are ancestral (present in the last common ancestor) and which are derived (evolved in one lineage after it diverged from the common ancestor). Cladograms are used across various biological disciplines, including systematics and comparative biology, to classify organisms and investigate their evolutionary histories.
https://www.youtube.com/watch?v=yWptHgesANE
"Phylogenetic" refers to anything related to phylogenetics, which is the branch of biology that deals with the evolutionary development and diversification of a species or group of organisms. Phylogenetics aims to understand the evolutionary relationships among various species or genes, typically represented in a phylogenetic tree or diagram. A phylogenetic tree is a branching diagram or "tree" showing the inferred evolutionary relationships among various biological species based upon similarities and differences in their physical or genetic characteristics.
The fundamental goal of phylogenetic studies is to reconstruct the lineage of organisms or genes to determine how they are related to one another. This involves:
Identifying the ancestral relationships and descent among species or genes.
Classifying organisms based on their evolutionary history.
Tracing the evolution of specific traits or genes across species over time.
Phylogenetic analyses use various types of data, including morphological (physical characteristics) and molecular (DNA, RNA, or protein sequences), to infer evolutionary relationships. These analyses help scientists understand the biodiversity and the history of life on Earth, contributing to fields such as conservation biology, systematics, and evolutionary biology.
Problem:
The tree below is unrooted. Where could you place the root so that A and B are not each other's closest relatives?
A) At the node where A joins B
B) At the node where D joins E
C) At the midpoint of the tree
https://www.youtube.com/watch?v=i-lQYXOWvD8
A tree is a mathematical structure which is used to model the actual evolutionary history of a group of sequences or organisms. This actual pattern of historical relationships is the phylogeny or evolutionary tree which we try and estimate. A tree consists of nodes connected by branches (also called edges). Terminal nodes (also called leaves, OTUs [Operational Taxonomic Units], or terminal taxa) represent sequences or organisms for which we have data; they may be either extant or extinct. Internal nodes represent hypothetical ancestors; the ancestor of all the sequences that comprise the tree is the root of the tree.
The nodes and branches of a tree may have various kinds of information associated with them. For example some methods of phylogeny reconstruction (e.g., parsimony) endeavour to reconstruct the characters of each hypothetical ancestor; most methods also estimate the amount of evolution that takes place between each node on the tree, which can be represent as branch lengths (or edge lengths). Trees with branch lengths are sometimes called weighted trees.
Problem:
What is the genetic distance between human and chimp as shown in the tree above?
A) 0.02 substitutions per site
B) 0.06 substitutions per site
C) 0.04 substitutions per site
https://www.youtube.com/watch?v=zqzmvviucHw
"Phylogenetic" refers to anything related to phylogenetics, which is the branch of biology that deals with the evolutionary development and diversification of a species or group of organisms. Phylogenetics aims to understand the evolutionary relationships among various species or genes, typically represented in a phylogenetic tree or diagram. A phylogenetic tree is a branching diagram or "tree" showing the inferred evolutionary relationships among various biological species based upon similarities and differences in their physical or genetic characteristics.
The fundamental goal of phylogenetic studies is to reconstruct the lineage of organisms or genes to determine how they are related to one another. This involves:
Identifying the ancestral relationships and descent among species or genes.
Classifying organisms based on their evolutionary history.
Tracing the evolution of specific traits or genes across species over time.
Phylogenetic analyses use various types of data, including morphological (physical characteristics) and molecular (DNA, RNA, or protein sequences), to infer evolutionary relationships. These analyses help scientists understand the biodiversity and the history of life on Earth, contributing to fields such as conservation biology, systematics, and evolutionary biology.
Problem:
The tree shown above is rooted. Which of the common ancestors occurred most recently?
А) The ancestor of human and chimpanzee
В) The ancestor of human, chimpanzee, mouse and rat
С) The ancestor of mouse and rat
https://www.youtube.com/watch?v=FV72PRQXeXY
P is the brother of Q and R. S is R's mother. T is P's father. Which of the following statements can
Blood relations are of considerable part of CAT and other MBA entrance exams. Around 3-4 questions make up its logical reasoning section. This topic is a scoring one if you are smooth with the understanding of family relations and family tree otherwise it can prove to be messy, confusing and time consuming. In recent times, we are most likely been detached with our family members and most live in nuclear families unlike in past times when the concept of Joint Families was an apparent part of our lifestyle. Thus, most of us hardly possess the idea of how family relations are intertwined and mixed up and how the branches flow through the family.
Problem:
P is the brother of Q and R. S is R's mother. T is P's father. Which of the following statements cannot be definitely true?
A) T is Q's father
B) S is P's mother
C) P is S's son
D) Q is T's son
https://www.youtube.com/watch?v=CjLmj8aU1j4
Pointing to a person, a man said to a woman, "His mother is the only daughter of your father." How..
Blood relations are of considerable part of CAT and other MBA entrance exams. Around 3-4 questions make up its logical reasoning section. This topic is a scoring one if you are smooth with the understanding of family relations and family tree otherwise it can prove to be messy, confusing and time consuming. In recent times, we are most likely been detached with our family members and most live in nuclear families unlike in past times when the concept of Joint Families was an apparent part of our lifestyle. Thus, most of us hardly possess the idea of how family relations are intertwined and mixed up and how the branches flow through the family.
Problem:
Pointing to a person, a man said to a woman, "His mother is the only daughter of your father." How was the woman related to the person?
A) Aunt
B) Mother *
C) Sister
D) Daughter
https://www.youtube.com/watch?v=tUp7OEHZoXs
Blood relations are of considerable part of CAT and other MBA entrance exams. Around 3-4 questions make up its logical reasoning section. This topic is a scoring one if you are smooth with the understanding of family relations and family tree otherwise it can prove to be messy, confusing and time consuming. In recent times, we are most likely been detached with our family members and most live in nuclear families unlike in past times when the concept of Joint Families was an apparent part of our lifestyle. Thus, most of us hardly possess the idea of how family relations are intertwined and mixed up and how the branches flow through the family.
Problem:
A girl introduced a boy as the son of' the daughter of the father of her uncle. The boy is girl's
A) Brother
B) Son
C) Uncle
D) Son-in-law
https://www.youtube.com/watch?v=fp6UqJtIxmY
Pointing out to a lady, a girl said, "She is the daughter-in-law of the grandmother of my father's..
Blood relations are of considerable part of CAT and other MBA entrance exams. Around 3-4 questions make up its logical reasoning section. This topic is a scoring one if you are smooth with the understanding of family relations and family tree otherwise it can prove to be messy, confusing and time consuming. In recent times, we are most likely been detached with our family members and most live in nuclear families unlike in past times when the concept of Joint Families was an apparent part of our lifestyle. Thus, most of us hardly possess the idea of how family relations are intertwined and mixed up and how the branches flow through the family.
Pointing out to a lady, a girl said, "She is the daughter-in-law of the grandmother of my father's only son." How is the lady related to the girl?
A) Sister-in-law
B) Mother
C) Aunt
D) Can't be determined
https://www.youtube.com/watch?v=qSn3eNtRdZg
In puzzle based questions, a web of relations can be formed, so do not solve such questions in a haste.
These questions are scoring and easy to solve, so do not panic if the question seems lengthy
In case of coding-decoding blood relation, use a pictorial description to solve the question. This will make the symbols and relation more clear.
Family Tree
To solve the problems in blood relation, one should know how to draw a family tree.
A family tree is a pictorial representation of genealogical data.
The following points help in drawing a family tree.
All the female members of the family are represented by a circle. The name of the person is written inside the circle for convenience.
All the male members of the family are represented by a square. The name of the person is written inside the square for convenience.
The relation between two members of the family is shown by connecting a double-headed arrow.
The spouse relation is represented by the two ends of a double-headed arrow.
All the family members of the upper generation are represented above in the family tree. Ex: father, mother, uncle, aunt etc. The logic can be extended by representing the grandparents above the parents in the family tree. Ex: grandfather and grandmother.
All the family members of the same generation are represented in the middle of the family tree. Ex: brothers, Sisters, cousins, wife, husband, etc.
All the family members of the next generation are represented below in the family tree.
P × Q means P is the brother of Q;
P # Q means P is the mother of Q;
P∗Q means P is the daughter of Q.
In A # B × C ∗ D, who is the father ?
A) D
B) B
C) C
D) Data is inadequate
https://www.youtube.com/watch?v=seFOyCzwanc
Blood relations are of considerable part of CAT and other MBA entrance exams. Around 3-4 questions make up its logical reasoning section. This topic is a scoring one if you are smooth with the understanding of family relations and family tree otherwise it can prove to be messy, confusing and time consuming. In recent times, we are most likely been detached with our family members and most live in nuclear families unlike in past times when the concept of Joint Families was an apparent part of our lifestyle. Thus, most of us hardly possess the idea of how family relations are intertwined and mixed up and how the branches flow through the family.
Problem: Introducing a man, a woman said, 'He is the only son of my mother's mother." How is the woman related to the man?
A) Mother
B) Aunt
C) Sister
D) Niece
https://www.youtube.com/watch?v=UnY8clv_YRw
Blood relations are of considerable part of CAT and other MBA entrance exams. Around 3-4 questions make up its logical reasoning section. This topic is a scoring one if you are smooth with the understanding of family relations and family tree otherwise it can prove to be messy, confusing and time consuming. In recent times, we are most likely been detached with our family members and most live in nuclear families unlike in past times when the concept of Joint Families was an apparent part of our lifestyle. Thus, most of us hardly possess the idea of how family relations are intertwined and mixed up and how the branches flow through the family.
Problem:
In a family, there are six members A, B, C, D, E and F.
A and B are a married couple, A being the male member. D is the only son of C, who is the brother of A. E is the sister of D. B is the daughter-in-law of F, whose husband has died. How is E related to C ?
A) Sister
B) Daughter
C) Cousin
D) Mother
https://www.youtube.com/watch?v=2Zrik3kNqb8
Blood relations are of considerable part of CAT and other MBA entrance exams. Around 3-4 questions make up its logical reasoning section. This topic is a scoring one if you are smooth with the understanding of family relations and family tree otherwise it can prove to be messy, confusing and time consuming. In recent times, we are most likely been detached with our family members and most live in nuclear families unlike in past times when the concept of Joint Families was an apparent part of our lifestyle. Thus, most of us hardly possess the idea of how family relations are intertwined and mixed up and how the branches flow through the family.
Problem:
A woman introduces a man as the son of the brother of her mother.
How is the man, related to the woman?
A) Nephew
B) Son
C) Cousin
D) Uncle to Grandson
https://www.youtube.com/watch?v=dzqbC71m_XY
Blood relations are of considerable part of CAT and other MBA entrance exams. Around 3-4 questions make up its logical reasoning section. This topic is a scoring one if you are smooth with the understanding of family relations and family tree otherwise it can prove to be messy, confusing and time consuming. In recent times, we are most likely been detached with our family members and most live in nuclear families unlike in past times when the concept of Joint Families was an apparent part of our lifestyle. Thus, most of us hardly possess the idea of how family relations are intertwined and mixed up and how the branches flow through the family.
Problem:
Pointing to a lady, a man said, "The son of her only brother is the brother of my wife." How is the lady related to the man?
A) Mother's sister
B) Grandmother
C) Mother-in-law
D) Sister of father-in-law
https://www.youtube.com/watch?v=f2oTUWdf1cM
In this video I will discuss, How you should Approach Problems Based on Coded Blood Relations and Get Accurate answer in Minimum time Possible.
Blood Relation often comes in Every Competitive Exams like SBI & Bank PO, CAT, RRB, etc.
Problem:
Read the following instructions:
A+B means A is the brother of B
A−B means A is the sister of B
A×B means A is the father of B
Which of the following means that C is the son of M?
1) M−N×C+F
2) F−C+N×M
3) N+M−F×C
4) M×N−C+F
https://www.youtube.com/watch?v=EKNdNtrn1-k
In this video I will discuss, How you should Approach Problems Based on Coded Blood Relations and Get Accurate answer in Minimum time Possible.
Blood Relation often comes in Every Competitive Exams like SBI & Bank PO, CAT, RRB, etc.
Problem:
Pointing to a man, a woman said, “His mother is the only daughter of my mother.” How is the woman related to the man?
A) Mother *
B) Daughter
C) Sister
D) Grandmother
https://www.youtube.com/watch?v=rIwHvIhdTbM