Lecture 3 Flashcards
Advantageous Intermediates
Intermediate step in evolution that might be advantageous in itself
Exaptation
process by which features acquire functions for which they were not originally adapted or selected
basically structures originally evolved for one purpose and then evolve further for another
Adaptation vs Exaptation
Adaptation
• Trait that evolved by natural selection and improves an organism’s ability to survive
and leave descendants
Exaptation
A trait that has been co-opted for a use other than the one for which it originated through natural selection
• utility of a structure for a biological role that was not part of the structure’s original evolutionary history
Multiplication of Species
Evolution produces new species by splitting and transforming older ones
Two Types of Speciation
Allopatric and Sympatric
Allopatric Speciation
Ancestral population geographically divided
Isolated sub populations evolve reproductive barriers between them
How can allopatric Speciation occur
Vicariant speciation and Founder effect
Vicariant Speciation
- Climate or geology causes populations to fragment
- Fragments of the ancestral population are left intact
- Fragmentation can occur in several species simultaneously
Founder effect
Occurs when a small number of individuals disperse to a distant place and form new populations
Sympatric Speciation
Diverging lineages co-occupy a geographic area
Different individuals within a species become
specialized for occupying different components of the environment
Biological Species Concept:
Characterizes species by their ability to interbreed to produce fertile offspring
Morphological Species Concept:
Characterizes species by body shape and other morphological features
Ecological Species Concept:
Characterizes species in terms of its ecological niche
True of False: Not all hybrids are infertile
True, some are fertile :)
