Published on May 8, 2014
Defining a species What defines two organisms as being two different species? A case study with black and pied stilts
Speciation of the black and pied stilts • Generally excepted that they are two distinct species • Black stilt - Himantopus novaezelandiae • Pied stilt – Himantopus himantopus http://basicbiology.net/gallery/animals/pied_stilt.jpghttp://www.mattjoneswildlifeimages.com/page40.htm
Background to their relationship • Believed to have originated from two separate colonisations from Australia pied stilts to New Zealand. • Black stilts - potentially 1 million years ago • Pied stilts – possilby as recent as 150 years ago • Differences – plumage (black vs black & white) – other morphological difference – behavioural differences.
Background to their relationship • IUCN red list status Black stilt – critically endangered Pied stilt – least concern • Black stilts mate for life • Due to a very low population size - between 58-78 adult birds - will sometimes mate and hybridize with pied stilts.
Definitions of species • Biological species concept – species defined as populations of individuals that can produce viable offspring. – Probably the most well-known definition of a species – Hybridisation? • Morphological species concept – classified as the same species if organisms fit into the same morphological criteria. – Classical definition going back to the days on Carl Linnaeus – the father of taxonomy
Definitions continued • Recognition species concept – species defined as organisms that recognise each other as potential mates. • Not well accepted due to hybridisation and phylogenetic • Phylogenetic species concept – species are a group of organisms that share a single common ancestor. • Concordance species concept – takes into account a range of diagnostic markers such as breeding, morphology, DNA markers. • Plus many more...
How do pied and black stilts fit in? • Morphological species concept: • The two species are similar in many ways. • Main difference in is the colour of plumage. • Black stilts - larger body size, longer beaks, shorter legs, longer wings. • But all are expected adaptations to a colder climate.
How do pied and black stilts fit in? • Phylogenetic species concept: • Pied stilt and black stilt have been shown to have two different haplotypes for mtDNA • i.e. two genetically different species • Mitochondrial genome <0.001% of the nuclear genome • Potentially not very representative • Concordance species concept: • The combination of morphological, mtDNA, isozyme and plumage markers indicate two distinct species
What does this all mean? • Firstly, as I said at the start – it is generally accepted that they are two distinct species. • It seems the phylogenetic and concordance species concepts hold more weight than other species definitions. • Illustrates how difficult it can be to classify a species. • Scratches the surface of the difficulties encountered by taxonomists.
How organisms adapt and survive in different environment.
Aplicación de ANOVA de una vía, modelo efectos fijos, en el problema de una empres...
Libros: Dra. Elisa Bertha Velázquez Rodríguez
In this talk we describe how the Fourth Paradigm for Data-Intensive Research is pr...
The inventor of modern scientific classification was Carolus Linnaeus (1707-1778) a Swedish botanist who classified and described more than 4,400 species ...
Theory and practice of grouping individuals into species, ... and naming and classifying our surroundings has ... Biological classification uses ...
A species is commonly defined as a population of organisms that can interbreed and reproduce under natural conditions. This definition has limitations ...
Biodiversity Recovery Unit Department of Conservation P. O. Box 10420 Wellington, New Zealand Classifying species according to threat of extinction
How many species are there? This is not an easy question to answer. About 1 ... When did scientists begin classifying living things?
Taxonomy: Classifying Life. At least 1.7 million species of living organisms have been discovered, and the list grows longer every year (especially of ...
Bacterial taxonomy is the taxonomy, i.e. the rank-based classification, of bacteria. ... If a species is published in a different peer review journal, ...
Classifying species. Biology Grade 11, lesson 2, Parkdale C.I. by Jelena Rakovac on 10 April 2012 Tweet. Comments (0) Please log in to add your ...
Assign: Unit 1: Preparation Activity page 4 - 7 Chapter 1: Classifying Life’s Diversity page 8 1.1: Identifying, Naming, and Classifying Species page 10
Kingdom to species Classification. You will remember from your Key Stage 3 studies that species with similar characteristics are put into groups, and that ...