Organisms are classified into a hierarchical classification that groups closely related individuals.
The species is the basic biological unit around which classifications are based.
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
Organisms are classified into a hierarchical classification that groups closely related individuals.
The species is the basic biological unit around which classifications are based.
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
The process by which a new species develops from the existing species is known as speciation.
Charles Darwin was the first to describe the role of natural selection in speciation in his 1859 book On the Origin of Species. He also identified sexual selection as a likely mechanism, but found it problematic.
A species can be defined as one or more populations of interbreeding organisms that are reproductively isolated in nature from all other organisms.
When populations no longer interbreed, they are thought to be separate species.
There are four geographic modes of speciation in nature, based on the extent to which speciating populations are isolated from one another: allopatric, peripatric, Parapatric, and sympatric.
Speciation may also be induced artificially, through animal husbandry, agriculture, or laboratory experiments.
Allopatric speciation: It is regarded as the most common type of speciation. It involves the physical separation of a species into two groups. This may occur due to climatic changes, movement of tectonic plates leading to the fragmentation of a mass of land, or eruption of a land mass, formation of waterways, or due to the presence of an impassable mountain range.
Parapatric mode of speciation: It occurs due to partial spatial isolation of populations, and is characterized by a small overlap in their ranges as well as significant gene flow amongst the populations. However, the gene flow reduces due to changes in the local conditions, and the two populations become reproductively isolated.
Sympatric mode of speciation: It involves the formation of new species due to a genetic divergence among a few members of the species inhabiting a single geographic area. Unlike the other modes of speciation, here genetic divergence does not arise due to increase in geographic distance, but occurs within the same niche.
Peripatric speciation was Proposed by Ernst Mayr. In this type of speciation, a small group of members inhabiting a peripheral region of the range undergo reproductive isolation to form a new species. Many a time, it is considered to be a variation of allopatric speciation.
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.
Kinds of taxonomic publications,taxonomic review ,revision, monograph,atlas,s...Anand P P
kinds of taxonomic publication mainly deals with different types of taxonomic publications.the taxonomy deals with several types of publications mainly that help to over all exchange of taxonomic information,its is a world wide taxonomic communication.
This presentation file has these contents:
Evolution
Convergent Evolution
Analogous structures
Divergent Evolution
Homologous structures
Parallel Evolution
Coevolution
Types of Evolution
Macroevolution
Microevolution
Importance of pattern of evolution
1.Definition and basic concepts of Biosystematics, , Historical perspectives of Biosystematics and Taxonomy, Stages of taxonomic procedures-alpha taxonomy, Beta taxonomy and Gamma taxonomy,
Neo taxonomy.
The process by which a new species develops from the existing species is known as speciation.
Charles Darwin was the first to describe the role of natural selection in speciation in his 1859 book On the Origin of Species. He also identified sexual selection as a likely mechanism, but found it problematic.
A species can be defined as one or more populations of interbreeding organisms that are reproductively isolated in nature from all other organisms.
When populations no longer interbreed, they are thought to be separate species.
There are four geographic modes of speciation in nature, based on the extent to which speciating populations are isolated from one another: allopatric, peripatric, Parapatric, and sympatric.
Speciation may also be induced artificially, through animal husbandry, agriculture, or laboratory experiments.
Allopatric speciation: It is regarded as the most common type of speciation. It involves the physical separation of a species into two groups. This may occur due to climatic changes, movement of tectonic plates leading to the fragmentation of a mass of land, or eruption of a land mass, formation of waterways, or due to the presence of an impassable mountain range.
Parapatric mode of speciation: It occurs due to partial spatial isolation of populations, and is characterized by a small overlap in their ranges as well as significant gene flow amongst the populations. However, the gene flow reduces due to changes in the local conditions, and the two populations become reproductively isolated.
Sympatric mode of speciation: It involves the formation of new species due to a genetic divergence among a few members of the species inhabiting a single geographic area. Unlike the other modes of speciation, here genetic divergence does not arise due to increase in geographic distance, but occurs within the same niche.
Peripatric speciation was Proposed by Ernst Mayr. In this type of speciation, a small group of members inhabiting a peripheral region of the range undergo reproductive isolation to form a new species. Many a time, it is considered to be a variation of allopatric speciation.
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.
Kinds of taxonomic publications,taxonomic review ,revision, monograph,atlas,s...Anand P P
kinds of taxonomic publication mainly deals with different types of taxonomic publications.the taxonomy deals with several types of publications mainly that help to over all exchange of taxonomic information,its is a world wide taxonomic communication.
This presentation file has these contents:
Evolution
Convergent Evolution
Analogous structures
Divergent Evolution
Homologous structures
Parallel Evolution
Coevolution
Types of Evolution
Macroevolution
Microevolution
Importance of pattern of evolution
1.Definition and basic concepts of Biosystematics, , Historical perspectives of Biosystematics and Taxonomy, Stages of taxonomic procedures-alpha taxonomy, Beta taxonomy and Gamma taxonomy,
Neo taxonomy.
This presentation is uploaded by Mahar Tanvir ul Hassan Tibbi Tarhana Samandry Faisalabad Pakistan. I am enrolled in University of Sargodha in MSc Zoology.
Speciation is the evolutionary process by which reproductively isolated biological populations evolve to become distinct species.There are few mechanisms through which this process can be well understood.
This is the first work, which introduce a new look to the Yemeni Geology. My interest in the Yemeni geology
started in 1987, when I wrote my first geological and technical report on Al-Kharg well, drilled in Al-Jawf Marib
Shabwa basin (Moscow, 1987; (Unpublished)). And my work on the former South Yemen regional geology
(Moscow, 1990; (Unpublished)) as a result of my fieldwork visits to the above-mentioned area.
During my work in the Republic of Yemen, (the research study area), for 8 years (1992-1999), I collected variably
detailed information of hundreds publications references on the pervious and the present geological activities in
Yemen for the period from 1852 until Today. That work led to the first classification and division for what I called the
Geological Research History Work (G.R.H.W) of the Republic of Yemen.
At the same time, I was highly interested in the whole pervious and present stratigraphic research related to the
Yemeni Lithostratigraphic Units and Nomenclature, because stratigraphic research pursued by different organizations,
companies and groups on different and indipendent lines was on the point of leading to choas. Studing a huge material
and data related to the pervious and the present geological activities in Yemen; such as final reports on geological
survey, different kinds of geophisical works, wells data (for more than 210 wells drilled in different area of the
republic of Yemen, where most of those wells located in the north-northeastern, east and south-southeastern part of
the Republic of Yemen(~75% of Yemeni sedimentary cover located in this area)), dry and wet sample analysis, well
site geologist geological descriptions, background gas indicatores, drillig results, log interpretations, core analysis, well
completion reports, lithostratigraphic units history (first time publication of the unit, its current meaning and definition),
lithostratigraphic and biostratigraphic description and indication of age; This research study work led at the beginning
to my work done on diferent geological wells data tables, geological well sections, correlation between wells (local
and regional), different kind of geological maps for spesific areas (this happened during my work in the Adeni Branch
of the Ministry of Oil and Mineral Resources) and led also to the first table on the whole Yemen Lithostratigraphic
Units and Nomenclture; my mapping and modelling to the whole eastern part of Yemen with the adjacent areas (this
happened during my research study work in Jilin University). This work is an extent to the great work done by many
4
interested geologists, scientific expeditions, organizations, local and forieghn companies, variably detailed information
of hundreds publications and references on the Yemeni geology.
The Yemeni Lithostratigraphic Units and Nomenclature table is projected to be a kind of huge encyclopedia. The
new thing is that names of all Yemeni lithostratigraphic units are presented in the above mentioned table in
accordance to their proven and high checked geological age. It is the first electronic and attributed table. Just point
your Computer mouse on the red triangle located on the right-upper corner of an interested lithostratigraphic units and
you are going to receive a brief geological information about it, especially in which Yemeni basins penetrated (Basin
name, It’s lithology, description and age).
The most important thing that this table led to my new explanation to the anomaly in the Yemeni
Lithostratigraphic Units and Nomenclature, having the same geological time line (the same age), by relating such
anomaly to the geological history of the area, especially the anomaly in tectonic activities and the process of
sedimentation; this table also gave me the right to suggest a new subdivision to the Yemeni Paleozoic sediments, into
two new depositional sequences, i.e. from young to old:
b. UPPER PALEOZOIC (Devonian – Permian) / TRIASSIC (Lower T
PowerPoint presentation that highlights chapters 13 and 14 in Campbell's Essential Biology (3rd. edition). It can also be used for Miller & Levine's Biology (2006 Ed.) for chapters 15-18.
25. Modes of Speciation Review within the range of the ancestral population Sympatric (sym = same, patric = place) a continuously distributed population Parapatric (para = beside, patric = place) a small population isolated at the edge of a larger populatin Peripatric (peri = near, patric = place) geographically isolated populations Allopatric (allo = other, patric = place)
