BIOL 1111 Lecture Notes - Lecture 3: Species Problem, Binomial Nomenclature, Carl Linnaeus
13 Jun 2018
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Chapter 19- Species
-Species are name specific; behavioural and genetic features are used for identification
Linnaean System of Classification
Linnaeus- developed binomial nomenclature (1700s)
Taxonomy- organizes large amounts of data used to identify, describe, classify and name organisms
based on evolutionary relationships, as well as give us the ability to link them to other species
Binomial Nomenclature- composed of Genus and specific epithet
-prevents confusion of common names
Taxonomic Hierarchy- arranges organisms into increasingly inclusive categories
Taxon- organisms within a particular hierarchy (an organism found in taxonomic hierarchy)
Species
-a group of organisms that can interbreed and produce fertile offspring
-the exceptions to this general definition is asexual organisms and species that hybridize
-under this concept, bacteria, androdioecious species, gynogenetic species
Morphological Species Concept
-all individuals of a species share measurable traits that distinguish them from individuals of other
species (diagnostic characters)
-some phenotypes difference is not due to genetics
Phylogenetics Species Concept
-a species is a group of organisms bound by a unique ancestry
-no indication of reproductive barriers
***species is difficult to define because definition is static but environment is changing, therefore
evolution is dynamic and the definition is always changing
Biological Species Concept
1. Interbreeding- gene flow mixes their genetic material, keeps the species together
2. Produce Fertile Offspring- genetic distinctiveness of each species; this produces viable species when
breeding with own species occurs but not favourable with other species
**Cohesiveness and Distinction**
Reproductive Isolation
-prevent gene pools mixing; reproductively isolated
Pre-zygotic: prevent successful mating
1. Ecological Isolation: to speies do’t iterat ofte eause they lie i differet haitats
2. Temporal Isolation: species breed at different times (season, year)
3. Behavioural Isolation: differences in behaviour (ex. Flight paths and lighting patterns in bugs)
4. Mechanical Isolation: morphological differences can prevent successful mating, reproductive
structures may be physically different (ex. Snail shells curled diff)
5. Gametic Isolation: sperm of one species may not be able to fertilize egg of another species (ex. Sea
urchins, all sperm and egg will come together but proteins on sperm will determine which egg and
sperm will come together)
-Post-zygotic: prevent zygote development (and/or fertility)
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Species are name specific; behavioural and genetic features are used for identification. Taxonomy- organizes large amounts of data used to identify, describe, classify and name organisms based on evolutionary relationships, as well as give us the ability to link them to other species. Binomial nomenclature- composed of genus and specific epithet. Taxonomic hierarchy- arranges organisms into increasingly inclusive categories. Taxon- organisms within a particular hierarchy (an organism found in taxonomic hierarchy) A group of organisms that can interbreed and produce fertile offspring. The exceptions to this general definition is asexual organisms and species that hybridize. Under this concept, bacteria, androdioecious species, gynogenetic species. All individuals of a species share measurable traits that distinguish them from individuals of other species (diagnostic characters) Some phenotypes difference is not due to genetics. A species is a group of organisms bound by a unique ancestry.
