The document discusses taxonomy and systematics. It defines taxonomy as the original description and naming of species, while systematics is the arrangement of species into evolutionary groups. It describes the historical development of classification systems from Linnaeus' focus on morphology to the modern three domain system based on molecular evidence. The key approaches of evolutionary systematics, numerical taxonomy, and phylogenetic systematics are also summarized.
DENTITION IN MAMMALS
The study of arrangement structure and number of types of teeth collectively is called as dentition. Teeth are present in the foetal as well as in adults of mammals, based on the presence of teeth Mammals are two types.
Edentata : In some animals teeth are absent hence called as edentate. e.g., Echidna or spiny ant-eater (Tachyglossus) the teeth are absent in all stages of life.
Dentata : Teeth are present in all mammals though a secon¬dary toothless condition is found in some mammals. Modern turtles and birds lack teeth. The adult platypus (Ornithorhynchus) bears epidermal teeth but no true teeth are present. In platypus embryonic teeth are replaced by horny epidermal teeth in adult.
Classification According to the Shape and Size of the Teeth:
Homodont:
Homodont or Isodont type of teeth is a condition where the teeth are all alike in their shape and size in the toothed whales e.g., Pinnipedians. Fishes, amphibians, reptiles and in the extinct toothed birds.
Heterodont
Heterodont condition is the usual feature in mammals, i.e. the teeth are distinguished according to their shape, size and function. The function is also different at different parts of the tooth row.
According to the Mode of Attachment of Teeth:
Thecodont : The teeth are lodged in bony sockets or alveoli of the jaw bone and capillaries and nerves enter the pulp cavity through the open tips of the hollow roots e.g., mammals, crocodiles and in some fishes.
Acrodont: The teeth are fused to the surface of the underlying jawbone. They have no roots and are attached to the edge of the jawbone by fibrous membrane e.g., fishes, amphibians and some reptiles.
Pleurodont:
The teeth are attached to the inner-side of the jawbone. The tooth touches the bone only with the outer surface of its root. In acrodont and pleurodont types of dentition, there are no roots, and nerves and blood vessels do not enter the pulp cavity at the base, e.g., Necturus (Amphibia) and some reptiles.
According to the Succession or Replace¬ment of Teeth:
This document will help you and will clear your concepts about the terms of Orthogenesis, Allometry & Adaptive Radiations, which are usually studied in evolution.
DENTITION IN MAMMALS
The study of arrangement structure and number of types of teeth collectively is called as dentition. Teeth are present in the foetal as well as in adults of mammals, based on the presence of teeth Mammals are two types.
Edentata : In some animals teeth are absent hence called as edentate. e.g., Echidna or spiny ant-eater (Tachyglossus) the teeth are absent in all stages of life.
Dentata : Teeth are present in all mammals though a secon¬dary toothless condition is found in some mammals. Modern turtles and birds lack teeth. The adult platypus (Ornithorhynchus) bears epidermal teeth but no true teeth are present. In platypus embryonic teeth are replaced by horny epidermal teeth in adult.
Classification According to the Shape and Size of the Teeth:
Homodont:
Homodont or Isodont type of teeth is a condition where the teeth are all alike in their shape and size in the toothed whales e.g., Pinnipedians. Fishes, amphibians, reptiles and in the extinct toothed birds.
Heterodont
Heterodont condition is the usual feature in mammals, i.e. the teeth are distinguished according to their shape, size and function. The function is also different at different parts of the tooth row.
According to the Mode of Attachment of Teeth:
Thecodont : The teeth are lodged in bony sockets or alveoli of the jaw bone and capillaries and nerves enter the pulp cavity through the open tips of the hollow roots e.g., mammals, crocodiles and in some fishes.
Acrodont: The teeth are fused to the surface of the underlying jawbone. They have no roots and are attached to the edge of the jawbone by fibrous membrane e.g., fishes, amphibians and some reptiles.
Pleurodont:
The teeth are attached to the inner-side of the jawbone. The tooth touches the bone only with the outer surface of its root. In acrodont and pleurodont types of dentition, there are no roots, and nerves and blood vessels do not enter the pulp cavity at the base, e.g., Necturus (Amphibia) and some reptiles.
According to the Succession or Replace¬ment of Teeth:
This document will help you and will clear your concepts about the terms of Orthogenesis, Allometry & Adaptive Radiations, which are usually studied in evolution.
Iczn(The International Commission on Zoological Nomenclature )Al Nahian Avro
The International Commission on Zoological Nomenclature (ICZN) acts as adviser and arbiter for the zoological community by generating and disseminating information on the correct use of the scientific names of animals. The ICZN is responsible for producing the International Code of Zoological Nomenclature - a set of rules for the naming of animals and the resolution of nomenclatural problems.
To determine the variation and the limitation between species, many concepts have been proposed.
When a taxonomist study a particular taxa, he/she must adopted a species concept and provide a species limitation to define this taxa.
Plant kingdom as other living kingdoms has a hierarchy structure ends mostly with species rank.
Species are one of the basic units to compare in almost all fields of biology.
A species is defined as the largest group of organisms in which two individuals are capable of reproducing fertile offspring, typically using sexual reproduction.
Definition of a species as a group of interbreeding individuals cannot be easily applied to organisms that reproduce only or mainly asexually.
If two lineages of oak look quite different, but occasionally form hybrids with each other, should we count them as different species?
Idea of a species is something that we humans invented for our own convenience.
‘‘No matter what variations occur in the individuals or the species, if they spring from the seed of one and the same plant, they are accidental variations and not such as distinguish a species permanently; one species never springs from the seed of another nor vice versa” - JOHN RAY.
Used a sexual system ‘‘natural system” for defining species - LINNAEUS.
‘‘A species is a collection of all the individuals which resemble each other more than they resemble anything else, which can by natural fecundation produce fertile individuals, and which reproduce themselves by generation, in such a manner that we may from analogy suppose them all to have sprung from one single individual” - DE CANDOLLE.
These slides contain short definitions and history of systematic zoology and taxonomy. The information in slides is taken from 2-3 taxonomy books and lectures from university at master level.
Classical and molecular taxonomic parameters, species concept, systematic gradation of animals, nomenclature, modern scheme of animal classification into sub-Kingdom, division, section, phyla and minor phyla
Affinities of Dipnoi or lungfishes towards fishes and amphibians and their phylogenetic relationship and position with respect to Chordates diversification.
They are not the father of amphibians rather they are the uncle of amphibians.
They might have originated from Latimaria like ancestor.
Moreover it is now confirmed that Dipnoi, Crossopterygii and Labirynthodint amphibians are originated from the common ancestor.
When a perfectly harmless animal resembles in its colour and shape, with a well protected species, the phenomenon is called mimicry.
The concept of mimicry was first given by H. W. Bates in 1862.
Mimicry is an important feature of organism which protect the animals against enemies. Mimicry often used as self defense which increases the survival value of organisms.
Origin of the Lateral Line System
Lateral line is a canal along the side of a fish containing pores that open into tubes supplied with sense organs sensitive to low vibrations.
Robert H. Denison explained the origin of the lateral line system. He explained that early vertebrates had a pore-canal system in the dermis which functioned as a primitive sensory system in detecting water movement.
Through the evidences from fossils, embryology and comparative anatomy, Denison (1966) established that the inner ear is closely related to the lateral line system. He found a distinct relationship between the pore canal system and the lateral line in Osteotraci.
The inner ear and the lateral line are developed from ectodermal thickenings, called dorso-lateral placodes. These have a number of similarities, including receptors with sensory hairs, and are both innervated by fibers in the acoustico-lateral area of the brain.
The pore canal system is present and developed in Osteostraci (ostracoderm).
It is also present in Heterostraci which is another group of ostracoderms and includes early vertebrates such as lungfishes and crossopterygians.
As its presence is extensive, it is reasonable to suggest that the pore canal system was a primitive character in early vertebrates .
In transverse sections also , it is very difficult to differentiate the pore canal system from a lateral line canal.
Structure of the Lateral Line System
Epidermal structures called neuromasts form the peripheral area of the lateral line.
Neuromasts consist of two types of cells, hair cells and supporting cells.
Hair cells have an epidermal origin and each hair cell has one high kynocyle (5-10 μm) and 30 to 150 short stereocilia (2-3 μm).
The number of hair cells in each neuromast depends on its size, and they can range from dozens to thousands.
Hair cells can be oriented in two opposite directions with each hair cell surrounded by supporting cells.
At the basal part of each hair cell, there are synaptic contacts with afferent and efferent nerve fibers. Afferent fibers, transmit signals to the neural centres of the lateral line and expand at the neuromast base. The regulation of hair cells is achieved by the action of efferent fibers.
Stereocilia and kinocilium of hair cells are immersed into a cupula and are located above the surface of the sensory epithelium.
The cupula is created by a gel-like media, which is secreted by non-receptor cells of the neuromast.
Iczn(The International Commission on Zoological Nomenclature )Al Nahian Avro
The International Commission on Zoological Nomenclature (ICZN) acts as adviser and arbiter for the zoological community by generating and disseminating information on the correct use of the scientific names of animals. The ICZN is responsible for producing the International Code of Zoological Nomenclature - a set of rules for the naming of animals and the resolution of nomenclatural problems.
To determine the variation and the limitation between species, many concepts have been proposed.
When a taxonomist study a particular taxa, he/she must adopted a species concept and provide a species limitation to define this taxa.
Plant kingdom as other living kingdoms has a hierarchy structure ends mostly with species rank.
Species are one of the basic units to compare in almost all fields of biology.
A species is defined as the largest group of organisms in which two individuals are capable of reproducing fertile offspring, typically using sexual reproduction.
Definition of a species as a group of interbreeding individuals cannot be easily applied to organisms that reproduce only or mainly asexually.
If two lineages of oak look quite different, but occasionally form hybrids with each other, should we count them as different species?
Idea of a species is something that we humans invented for our own convenience.
‘‘No matter what variations occur in the individuals or the species, if they spring from the seed of one and the same plant, they are accidental variations and not such as distinguish a species permanently; one species never springs from the seed of another nor vice versa” - JOHN RAY.
Used a sexual system ‘‘natural system” for defining species - LINNAEUS.
‘‘A species is a collection of all the individuals which resemble each other more than they resemble anything else, which can by natural fecundation produce fertile individuals, and which reproduce themselves by generation, in such a manner that we may from analogy suppose them all to have sprung from one single individual” - DE CANDOLLE.
These slides contain short definitions and history of systematic zoology and taxonomy. The information in slides is taken from 2-3 taxonomy books and lectures from university at master level.
Classical and molecular taxonomic parameters, species concept, systematic gradation of animals, nomenclature, modern scheme of animal classification into sub-Kingdom, division, section, phyla and minor phyla
Affinities of Dipnoi or lungfishes towards fishes and amphibians and their phylogenetic relationship and position with respect to Chordates diversification.
They are not the father of amphibians rather they are the uncle of amphibians.
They might have originated from Latimaria like ancestor.
Moreover it is now confirmed that Dipnoi, Crossopterygii and Labirynthodint amphibians are originated from the common ancestor.
When a perfectly harmless animal resembles in its colour and shape, with a well protected species, the phenomenon is called mimicry.
The concept of mimicry was first given by H. W. Bates in 1862.
Mimicry is an important feature of organism which protect the animals against enemies. Mimicry often used as self defense which increases the survival value of organisms.
Origin of the Lateral Line System
Lateral line is a canal along the side of a fish containing pores that open into tubes supplied with sense organs sensitive to low vibrations.
Robert H. Denison explained the origin of the lateral line system. He explained that early vertebrates had a pore-canal system in the dermis which functioned as a primitive sensory system in detecting water movement.
Through the evidences from fossils, embryology and comparative anatomy, Denison (1966) established that the inner ear is closely related to the lateral line system. He found a distinct relationship between the pore canal system and the lateral line in Osteotraci.
The inner ear and the lateral line are developed from ectodermal thickenings, called dorso-lateral placodes. These have a number of similarities, including receptors with sensory hairs, and are both innervated by fibers in the acoustico-lateral area of the brain.
The pore canal system is present and developed in Osteostraci (ostracoderm).
It is also present in Heterostraci which is another group of ostracoderms and includes early vertebrates such as lungfishes and crossopterygians.
As its presence is extensive, it is reasonable to suggest that the pore canal system was a primitive character in early vertebrates .
In transverse sections also , it is very difficult to differentiate the pore canal system from a lateral line canal.
Structure of the Lateral Line System
Epidermal structures called neuromasts form the peripheral area of the lateral line.
Neuromasts consist of two types of cells, hair cells and supporting cells.
Hair cells have an epidermal origin and each hair cell has one high kynocyle (5-10 μm) and 30 to 150 short stereocilia (2-3 μm).
The number of hair cells in each neuromast depends on its size, and they can range from dozens to thousands.
Hair cells can be oriented in two opposite directions with each hair cell surrounded by supporting cells.
At the basal part of each hair cell, there are synaptic contacts with afferent and efferent nerve fibers. Afferent fibers, transmit signals to the neural centres of the lateral line and expand at the neuromast base. The regulation of hair cells is achieved by the action of efferent fibers.
Stereocilia and kinocilium of hair cells are immersed into a cupula and are located above the surface of the sensory epithelium.
The cupula is created by a gel-like media, which is secreted by non-receptor cells of the neuromast.
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
The use of Nauplii and metanauplii artemia in aquaculture (brine shrimp).pptxMAGOTI ERNEST
Although Artemia has been known to man for centuries, its use as a food for the culture of larval organisms apparently began only in the 1930s, when several investigators found that it made an excellent food for newly hatched fish larvae (Litvinenko et al., 2023). As aquaculture developed in the 1960s and ‘70s, the use of Artemia also became more widespread, due both to its convenience and to its nutritional value for larval organisms (Arenas-Pardo et al., 2024). The fact that Artemia dormant cysts can be stored for long periods in cans, and then used as an off-the-shelf food requiring only 24 h of incubation makes them the most convenient, least labor-intensive, live food available for aquaculture (Sorgeloos & Roubach, 2021). The nutritional value of Artemia, especially for marine organisms, is not constant, but varies both geographically and temporally. During the last decade, however, both the causes of Artemia nutritional variability and methods to improve poorquality Artemia have been identified (Loufi et al., 2024).
Brine shrimp (Artemia spp.) are used in marine aquaculture worldwide. Annually, more than 2,000 metric tons of dry cysts are used for cultivation of fish, crustacean, and shellfish larva. Brine shrimp are important to aquaculture because newly hatched brine shrimp nauplii (larvae) provide a food source for many fish fry (Mozanzadeh et al., 2021). Culture and harvesting of brine shrimp eggs represents another aspect of the aquaculture industry. Nauplii and metanauplii of Artemia, commonly known as brine shrimp, play a crucial role in aquaculture due to their nutritional value and suitability as live feed for many aquatic species, particularly in larval stages (Sorgeloos & Roubach, 2021).
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
Phenomics assisted breeding in crop improvementIshaGoswami9
As the population is increasing and will reach about 9 billion upto 2050. Also due to climate change, it is difficult to meet the food requirement of such a large population. Facing the challenges presented by resource shortages, climate
change, and increasing global population, crop yield and quality need to be improved in a sustainable way over the coming decades. Genetic improvement by breeding is the best way to increase crop productivity. With the rapid progression of functional
genomics, an increasing number of crop genomes have been sequenced and dozens of genes influencing key agronomic traits have been identified. However, current genome sequence information has not been adequately exploited for understanding
the complex characteristics of multiple gene, owing to a lack of crop phenotypic data. Efficient, automatic, and accurate technologies and platforms that can capture phenotypic data that can
be linked to genomics information for crop improvement at all growth stages have become as important as genotyping. Thus,
high-throughput phenotyping has become the major bottleneck restricting crop breeding. Plant phenomics has been defined as the high-throughput, accurate acquisition and analysis of multi-dimensional phenotypes
during crop growing stages at the organism level, including the cell, tissue, organ, individual plant, plot, and field levels. With the rapid development of novel sensors, imaging technology,
and analysis methods, numerous infrastructure platforms have been developed for phenotyping.
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
Nucleophilic Addition of carbonyl compounds.pptxSSR02
Nucleophilic addition is the most important reaction of carbonyls. Not just aldehydes and ketones, but also carboxylic acid derivatives in general.
Carbonyls undergo addition reactions with a large range of nucleophiles.
Comparing the relative basicity of the nucleophile and the product is extremely helpful in determining how reversible the addition reaction is. Reactions with Grignards and hydrides are irreversible. Reactions with weak bases like halides and carboxylates generally don’t happen.
Electronic effects (inductive effects, electron donation) have a large impact on reactivity.
Large groups adjacent to the carbonyl will slow the rate of reaction.
Neutral nucleophiles can also add to carbonyls, although their additions are generally slower and more reversible. Acid catalysis is sometimes employed to increase the rate of addition.
2. The study of kinds and diversity of organisms
and the evolutionary relationships among them is
called systematics or taxonomy.
The study of systematics gives the order and
relationship among the organisms. This
relationship arises from evolutionary processes.
The organisms are organizes into groups (taxa).
This grouping grouping is based on degree of
evolutionary relatedness.
KHAWAJA TAIMOR SHAHID
3. Taxonomy
The original description of
species is called taxonomy.
Systematics
The arrangement of species
into evolutionary groups is
called systematics.
KHAWAJA TAIMOR SHAHID
4. Taxonomic hierarchy based on
morphology Taxonomic hierarchy based on
evolution Karl von Linne gave the
modern classification
system.
He believed that different
species could be grouped
into same categories.
This grouping is based on
the similarities b/w them.
The group of animal with
similar characteristics forms
a e.g., house fly
similar with other flies.
Von Linne did not accept
evolution. But his many
grouping show evolutionary
relationship.
Morphological similarities
b/w two animals have a
genetic basis – it give rise to
common evolutionary
history.
The members of same taxonomic group are more closely related
to each other than to members of different taxa. KHAWAJA TAIMOR SHAHID
6. The assignment of a distinct name to each species is called
nomenclature.
There are two problems with common names.
First, common names vary
from country to country
even region to region.
So the there must be a
system of naming
organisms. So biologists
may communicate easily
with each other.
Second, a common name
often does not specify a
particular species.
E.g., different kinds of
pillbugs & crayfish cannot
be differentiated easily,
same class (Crustacea) but
diff. orders (Isopoda &
Decapoda, repectively).
KHAWAJA TAIMOR SHAHID
7. There are followings rules:
Genus of
an animal
begins with
a capital
letter.
The species
name
begins with
a small
letter.
These names
are derived
from Latin –
so italicized
or underlined,
human-
Homo
sapiens.
The
binomial
name can
be
abbreviated
i.e., H.
sapiens.
KHAWAJA TAIMOR SHAHID
10. Molecular approaches includes study of molecules
like proteins, DNA, RNA of different species.
These approaches provide information which is used
for taxonomic studies.
For example, gene products (proteins) are same in
certain animals i.e., show the closeness b/w animals.
So we easily compare the sequence of amino acids
and nucleotides of various organisms through this
techniques.
In this way the constant mutation rate is seen. The
constant mutation of organism is called molecular
clock.
KHAWAJA TAIMOR SHAHID
11. Sequencing nuclear DNA and mitochondrial
DNA (mDNA) helps taxonomists to study the
taxonomic relationships.
mDNA is useful in taxonomic studies because:
◦ Mitochondria have their own genetic system.
◦ They are inherited through cytoplasm, which means
it comes from mother. So we can check the
maternal lineages.
◦ mDNA is in small quantity so it changes at a
relatively constant rate.
KHAWAJA TAIMOR SHAHID
12. No doubt that molecular techniques are helps
taxonomists but traditional techniques have its own
importance. So they run complement to each other.
The molecular clocks used to determine rates of
evolutionary changes. This information helps us to
fill the time gaps in the fossil record.
Molecular clocks run at different rate and depends
on:
◦ Sequence if amino acids in proteins.
◦ Sequence of bases in mDNA.
◦ Sequence of bases in nuclear DNA.
◦ Data from different evolutionary lineages.
KHAWAJA TAIMOR SHAHID
15. In 1969, Robert H. Whittaker describes a system of
classification. The basis of classification of Whittaker
is:
◦ Cellular organization
◦ Mode of nutrition
There are following five kingdoms:
◦ Monera – prokaryotes (bacteria and cyano bacteria)
◦ Protista – eukaryotes (amoeba, paramecium etc.)
◦ Plantae – eukaryotic, multicellular & photosynthetic. Non-
motile. ( plants)
◦ Fungi – eukaryotic, multicellular & decomposers. Non-
motile. (absorb organic matter)
◦ Animalia – eukaryotic, multicellular & feed by ingestion .
Motile.
KHAWAJA TAIMOR SHAHID
16. The early five kingdom do not follow
the evolutionary lineages.
Importance of ribosomal RNA in
domain classification system.?
◦Problems of study of fossils
◦Ribosomal RNA & evolutionary
conservation
◦Basis of domain classification system
KHAWAJA TAIMOR SHAHID
17. There were very little fossil evidence
is present of 2 billion years ago.
Therefore, ribosomal RNA studies
were used.
It provides evidence about the
relationships among the organism of
this 2 billion year period.
KHAWAJA TAIMOR SHAHID
18. Ribosomal RNA is excellent for studying the
evolution of early life on earth. The following
properties makes it excellent:
◦ It is an ancient molecule.
◦ It is present in all organisms.
◦ It changes very slowly. This slowness of change is
called evolutionary conservation.
We can easily compare & study the link b/w
closely related organisms. There must be a
little difference but the relationship to some
ancestral molecule are still present.
KHAWAJA TAIMOR SHAHID
19. Molecular systematists compare the base
sequences of ribosomal RNA of different
organisms.
They enter these data into computer programs
and examine all possible relationship among
different organisms.
On the basis of studies of ribosomal, the
systematists concluded that all life shares a
common ancestor.
They find three major evolutionary lineages –
called the domain.
KHAWAJA TAIMOR SHAHID
20. Archaea
• These are prokaryotic
microbes. They live in
extreme environment i.e.,
high temperature, anaerobic
environment.
• The archaea are the most
primitive life form.
Eubacteria
• They include true bacteria.
• These are prokaryotic
microorganisms.
Eukarya
• The Eukarya include all
eukaryotic organisms.
The Eukarya arose about
1.5 billion years ago.
• The Eukarya diverged
more recently than the
Eubacteria from the
Archaea.
KHAWAJA TAIMOR SHAHID
23. There are certain classification
groups are made to classify them. As
follows:
◦Monophyletic groups
◦Polyphyletic groups
◦Paraphyletic groups
KHAWAJA TAIMOR SHAHID
24. The groups showing similarities due to single
ancestors are called monophyletic groups. & the
classification is monophyletic classification.
The species should have single ancestral species. All
the descendants should arise from this single
ancestral species.
The taxonomists look for characters, (indicate
relatedness), for searching out monophyletic groups.
A character is anything that has a genetic basis and
can be measured from an anatomical feature to a
sequence of nitrogenous bases in DNA or RNA.
KHAWAJA TAIMOR SHAHID
25. The group showing similarities but
have separate ancestors are called
polyphyletic groups.
Each group has a single ancestor.
Polyphyletic group indicate
insufficient knowledge of the group.
KHAWAJA TAIMOR SHAHID
26. A group formed temporarily for some
lineage is called Paraphyletic groups.
Paraphyletic groups are formed due to
insufficient knowledge of the group.
Simply, taxonomic grouping that is derived
from a single ancestor but does not include all
members of the family group is called a
Paraphyletic group.
KHAWAJA TAIMOR SHAHID
29. There are certain disagreements are present in
animal systematics & these are:
◦ In the methods of investigation.
◦ In the use of data in describing distant evolutionary
relationship.
So, on the basis of these differences three
contemporary schools of systematics exist:
◦ Evolutionary systematics (traditional approach)
◦ Numerical taxonomy
◦ Phylogenetic systematics (cladistics)
KHAWAJA TAIMOR SHAHID
30. The systematics in which evolutionary relationship are developed by study
of fossils of ancestors of closely related animals is called evolutionary
systematics.
Its basic assumption is that organisms closely are related to an
ancestor.
According to this there are two similarities b/w organism:
◦ Homologies: The resemblances that result from common ancestry are called
homology. It is called divergent evolution. E.g., wing of bird and arm of
human.
◦ Analogies: The resemblances that result from organisms adapting under
similar evolutionary pressures are called analogy. It is called convergent
evolution. E.g., wings of birds and insects.
Evolutionary systematics can be shown on phylogenetic trees. The
organisms are grouped according to their evolutionary
relationships in phylogenetic tree.
KHAWAJA TAIMOR SHAHID
32. The founder of numerical taxonomy believed that there
are no criteria for grouping taxa.
It is opposite to the evolutionary systematics.
Numerical taxonomists use mathematical models and computer-aided
techniques to group samples of organisms according to overall similarity.
There are two differences b/w evolutionary and numerical taxonomy:
1. Numerical taxonomists do not distinguish b/w homologies
and analogies. Numerical taxonomists admit that analogies
exist.
2. Numerical taxonomists limit discussion of evolutionary
relationships to closely related taxa.
Numerical taxonomy is the least popular of the three taxonomic schools.
However, all taxonomists use the computer programs that numerical
taxonomists developed.
KHAWAJA TAIMOR SHAHID
33. The development of evolutionary relationship among the
organism on the basis of study of fossil, analysis and tests
is called phylogenetic systematics.
The cladists are mainly check/study the genealogical
relationship among monophylretic groups of organisms and
use more testing and analysis. Therefore it is more scientific
than evolutionary systematics.
The cladists differentiate b/w homologies & analogies.
However, they believe that homologies of recent origin are
most useful in phylogenetic studies.
The cladists study two types of characters:
◦ Symplesiomorphies
◦ Synapomorphies
KHAWAJA TAIMOR SHAHID
35. Symplesiomorphies Synapomorphies
(Gr. sym, together plesio, near
morphe, form).
The characters that all
members of a group share are
called basic characters or
Symplesiomorphies.
These characters are homologies
that may indicate a shared
ancestry.
But they are useless in describing
relationships within the group.
To decide what character is
ancestral for a group of
organisms, cladists look for a
related group of organisms, called
an out-group.
(Gr. syn, together apo, away
morphe, form).
Characters that have arisen
since common ancestry with the
out-group are called derived
characters or synapomorphies.
Simply, A character that can be
used to distinguish an animal
from other animals within the
group is called a
Synapomorphies.
KHAWAJA TAIMOR SHAHID
36. Interpreting Cladograms. This hypothetical cladogram shows five
taxa (1–5) and the characters (A–H) used in deriving the taxonomic
relationships. Character A is symplesiomorphic for the entire group.
Taxon 5 is the outgroup because it shares only that ancestral character
with taxa 1–4. All other characters are more recently derived. What
single character is a synapomorphy for taxa 1 and 2, separating them
from all other taxa?
KHAWAJA TAIMOR SHAHID
39. The hypothetical lineage shown in diagram is called a
cladogram.
Cladograms give sequence in the origin of derived characters.
A cladogram is a family tree.
It follows a hypothesis of monophyletic lineages. New data is
formed in the form of newly investigated character. (or it gives
reinterpretation of old data.
This new data is used to test the hypothesis the cladogram.
KHAWAJA TAIMOR SHAHID
40. Cladogram of vertebrate phylogeny
This cladogram shows the evolutionary relationship among the vertebrates. KHAWAJA TAIMOR SHAHID
41. The character of extraembryonic membranes is a synapomorphy and it
is used to define the clade containing the reptiles, birds, and mammals.
But these characters are not present in any of the fish taxa or the
cladogram.
The
KHAWAJA TAIMOR SHAHID
45. Showing relationship above the species
Evolution at specie level
Showing modern representatives
Showing modern representatives at tip of branches
Ladder like progression
Problem of extinction
Representation as inverted cone
KHAWAJA TAIMOR SHAHID
46. The evolutionary-tree diagrams can help to clarify
evolutionary relationships and timescales. But these show
relationships among levels of classification above the species.
So they are often a source of misunderstanding.
2. Evolution at specie level
• Evolution occurs in species groups (populations), not at higher
taxonomic levels. Therefore, showing phyla or classes as
ancestral is misleading.
3. Showing modern representatives
• Some phyla or classes are shown as ancestral, modern
representatives of these “ancestral phyla” . These have just as
long an evolutionary history as animals in other taxonomic
groups. These groups may have descended from the common
ancestor.
KHAWAJA TAIMOR SHAHID
47. All the modern representatives are shown at tips of a
tree branch. They may be very different from
ancestral species. Zoologists use modern
representatives to help visualize general
characteristics of an ancestral species. But they never
specify details of the ancestor’s structure, function, or
ecology.
5. Ladder like progression
• The evolutionary trees often show a ladder like
progression of increasing complexity. But evolution is
resulted in reduced complexity. So this is misleading.
KHAWAJA TAIMOR SHAHID
48. In many cases, evolution does not lead to phenotypes that
permit survival under changing conditions. Therefore
extinction occurs. These are not shown in tree diagram.
7. Representation as inverted cone
• The common phylogeny as an inverted cone or a tree but with
a narrow trunk and many higher branches. It is also
misleading. It shows that evolution is a continuous process of
increasing diversification. The fossil records show that this is
often wrong.
• For example, 20 to 30 groups of echinoderms are in the fossil
record, but there are only five modern groups. This
evolutionary lineage underwent rapid initial evolutionary
diversification. After the initial diversification, extinction -not
further diversification- was the rule. Paleontologist Stephen J.
Gould uses the term contingency to refer to rapid evolutionary
explosion followed by a high likelihood of extinction.
KHAWAJA TAIMOR SHAHID
49. The common phylogeny as an inverted cone or a tree
but with a narrow trunk and many higher branches. It
is also misleading. It shows that evolution is a
continuous process of increasing diversification. The
fossil records show that this is often wrong.
For example, 20 to 30 groups of echinoderms are in
the fossil record, but there are only five modern
groups. This evolutionary lineage underwent rapid
initial evolutionary diversification. After the initial
diversification, extinction -not further diversification-
was the rule. Paleontologist Stephen J. Gould uses
the term contingency to refer to rapid evolutionary
explosion followed by a high likelihood of extinction.
KHAWAJA TAIMOR SHAHID