A 3.1 SL Diversity of organism Flashcards
Who observed variation between species? And why is it important?
Charles Darwin observed that typical populations vary in many respects, and that this variation is an important factor for evolution. If all individuals in a population were identical, there would be no way of some individuals being favoured more than others.
What was originally the term species used for? And what did Carl Linneaeus discorver?
Originally biologists used the term “species” for a group of organisms with shared traits. Carl Linneaeus, a biologist working on classifying organism, described the outer form and inner structure of typical members of a species according to its morphology.
How did Carl Linneaeus classify plants?
Carl Linnaeus classified plants based on the number, arrangement and fusion of sexual parts. Or, grouping organisms according to the presence of shells would put snails & turtles in the same group….
What is the morphological species concept?
The morphological species concept describes species based on how they look (morphology). This is the traditional way of classification, but it can be very misleading for identifying species. Often two species look similar, but in reality they have evolved differently for a very long time.
Why do biologists group organisms?
Biologists group organisms to represent similarities and proposed relationships. Classification systems change with expanding knowledge about new and well-known organisms. The science of classification is referred to as taxonomy.
What is binomial system for naming organisms?
Categorising organism is easier if a universal and internationally accepted system for naming is used. This two-part name consists of the genus name and the species name.
What is smallest taxonomic group? And how do you incorporate it in the naming system?
How can you recognise subspecies?
three names
What is a species?
A group of individuals of common ancestry that closely resemble each other & that are normally capable of interbreeding to produce fertile offspring.
What is variation?
Variation = Differences in any aspect of an organism.
What is a defining feature of life?
All living organisms show variation. No two individuals are identical in all of their traits. This variation is one of defining features of life.
What has been developed due to variation between organisms?
Bc of large amount of variation between organisms, we have developed systems of classification to group & organise our knowledge about them. These systems structure our understanding & allow for clearer communication between ppl studying organisms around world. ‘Modern’ system for classifying living organisms was published in 1735 by Carl Linnaeus, a Swedish naturalist.
What is a classification of organisms?
A system of organising knowledge on all living things based upon their characteristics & more recently their DNA.
How did Linnaeus classify organisms into species?
Linnaeus classified organisms into species based on shared morphological characteristics. Individuals of same species tend to look more similar to each other than to members of other species. This is original morphological concept of a species.
Define morphological species concept
The morphological species concept relies on morphological data & emphasizes groups of physical trait that are unique to each species.
What is the original morphological concept of a species?
Classification of organisms into species based upon shared morphological (physical) characteristics.
How dos the morphological concept work from lions and tigers?
Take lions (Panthera leo) & tigers (Panthera tigris), these two species of large cats are closely related but separate species, with recognisable, distinct characteristics. Once you recognise what those characteristics are, you wouldn’t confuse a tiger and a lion.
What naming convention did Linnaeus developed for naming species?
Today, this is known as binomial nomenclature. Species are named using both their genus and species names. Genus name comes 1st & 1st letter is capitalised, followed by species name in lowercase. This is put in italics within text or underlined when handwritten. E.g. Homo sapiens, Homo neanderthalensis, Panthera leo & Panthera tigris.
Define binomial nomenclature
Binomial nomenclature: Naming system for living organisms using 2 names for each species; genus followed by species.
Define genus
Genus: Taxonomic group below family & above species. It’s used in binomial nomenclature along with species, as 1st of 2 names.
What do species with the same genus share in common?
Species sharing a genus share common characteristics.
How are species binomial names created?
Names themselves are based on Latin & have varying origins, from descriptions of specific defining features to names of ppl who 1st discovered or described the species. E.g. humpback whale = Megaptera novaeangliae, meaning big-winged New Englander referring to their extremely long pectoral fins & 1 of locations in which they were 1st encountered by whalers. Dall’s porpoise, Phocoenoides dalli, is named after American naturalist William Healey Dall, who collected 1st specimen of species.
Define sexual dysmorphisms
When the male and female of a species look significantly different. Often having completely different features and appearance.
How do we define species that look so similar they can’t be easily distinguished from each other? How do we classify when there is sexual dimorphism within a species and males and females have very different characteristics?
To deal with these issues, among others, the biological species concept was developed.
