1 Species Concept Flashcards
Why do we need to know what a
species is?
- Utility
- Basic rank of classification
- Order and retrieve information on individual specimens in collections or data banks.
- Species are important in biodiversity issues
Delimit groups of organisms along natural fault lines, so that approximately the same groupings can be recovered by independent observers.
Utility
Species are important in biodiversity issues
- Conservation, ecology, legislation concerns focus on this level
- Something quantifiable
What is the study of life?
Biology
Species Concept:
- A species is a population or group of populations whose members have the potential to interbreed and produce fertile offspring.
- Reproductive barriers prevent gene flow
between 2 different species
Biological Species Concept
2 Types of Reproductive Barriers between Species
- Prezygotic Barriers
- Postzygotic Barriers
Reproductive Barriers between Species (Prezygotic):
different areas with physical barrier
Geographical Isolation
Reproductive Barriers between Species (Prezygotic):
same area but different habitats
Ecological Isolation
Reproductive Barriers between Species (Prezygotic):
different mating times
Temporal isolation
Reproductive Barriers between Species (Prezygotic):
no sexual attraction
Behavioral isolation
Reproductive Barriers between Species (Prezygotic):
incompatible mating organs
Mechanical isolation
incompatible gametes
Gametic isolation
Reproductive barriers between species (Postzygotic):
hybrids do not survive
Hybrid inviability
Reproductive barriers between species (Postzygotic):
hybrids do not produce
functional gametes
Hybrid sterility
Reproductive barriers between species (Postzygotic):
offspring of hybrids are
weak or infertile
Hybrid breakdown
Different definitions of the species concept:
- Difficult to apply on organisms which are not known to undergo sexual reproduction or where sexual barriers cannot be determined
Biological species concept
Different definitions of the species concept:
- Used gaps in morphology to delimit species
- Criterion can be extended to ecology, behaviour or genetics
Morphological species concept
Morphological Diagnosis Limitations.
- phenotypic plasticity and genetic variability.
- morphologically cryptic taxa overlooked.
- morphological keys are life stage and/or gender selective.
- demands high level of expertise.
Different definitions of the species concept:
- A species is a cluster of organisms
that represent a genealogy or a
lineage of descent.
Evolutionary species concept
It identifies unknown individuals through
DNA sequences
DNA barcoding
Methodology of DNA Barcoding
- DNA extraction
- PCR amplification
- DNA sequencing
Applications of DNA Barcoding
- discovery of new species
- biodiversity assessment
- phylogenetic studies of closely related taxa.
- regulation of export/import of endangered species.
Different definitions of the species concept:
- Proponents: van Valen, Mayr, George Evelyn Hutchinson
- It is where you are and what you are doing that matters.
- Occupancy of an ecological niche
Ecological species concept
the entirety of environmental factors that tend to suit and allow an animal or plant species to survive in its habitat; the way of life of a species.
Occupancy of an ecological niche
Objections to the species concept:
Species are not individual real objects but instead are _________.
manmade constructs.
________ are in the front line of species identification.
Taxonomists
Classification is not the basic biological concept, D___ o_ L___ is.
Diversity of Life
What is it important to study the similarities and differences of organisms?
So that they can be use to better understand the changes that occurred among organisms through time.
