Origin of Species Flashcards
Module 1 (Leture 3)
True or False
Survival of the fittest’ means survival of the strongest.
False
Genes from the individuals that leave the most offspring will survive
Survival of the most reproductively fit (not strongest)
True or False
Evolution is not random.
True
Genetic variability in populations has a random aspect to it
because it is created by mutations. Mutations are random. The force
that drives evolution is natural selection and it is not random.
True or False
Are mutations favourable and unfavourable.
True
Most mutations are unfavourable or neutral. But some
mutations confer favourable phenotypes. Genetic variability within a population is also favourable because it allows a population to respond
to environmental change.
True or False
Every feature can be explained as an adaptation.
False
Features can be 1) the result of history (e.g. the amino acid code),
2) just a by-product (e.g. the colour of blood), or 3) an outdated
adaptation (e.g. relationship with extinct organism)
How do complex traits evolve? (2)
- Advantageous Intermediates
- Exaptation
Intermediate step might be advantageous in
itself
Advantageous Intermediates
Process by which features acquire
functions for which they were not originally adapted or selected
Structure originally evolves for one purpose and
then evolve further for another
Exaptation
Bird feathers are considered an exaptation ______ adaptation _______
- for flight
- for thermoregulation
Trait that evolved by natural selection and improves an organism’s ability to survive and leave descendants
Adaptation
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
Exaptation
Modern Synthesis = _____________ + _____________
- Microevolution
- Macroevolution
Pertains to evolutionary changes in frequencies of variant forms of genes within populations
Microevolution
Pertains to evolution on a long timescale.
Origins of new structures, species, mass extinctions etc…
Macroevolution
Patterns in macroevolution (3)
- Stasis
- Lineage splitting
- Extinction
How does evolution produces new species?
Splitting and transforming older ones
Two Types of Speciation
Allopatric and Sympatric
Ancestral population geographically divided
Isolated subpopulations evolve reproductive barriers between them
Allopatric Speciation
Two types of allopatric speciation
Vacariant Speciation and Founder effect
Climate or geology causes populations to fragment
Fragments of the ancestral population are left intact
Fragmentation can occur in several species simultaneously
Vacariant Speciation
Occurs when a small number of individuals disperse to a distant place and form
new populations
Founder effect
Diverging lineages co-occupy a geographic area
Different individuals within a species become specialized for occupying different components of the
environment
Sympatric speciation
Less common type of speciation between Sympatric and Allopatric Speciation?
Sympatric speciation
What type of speciation is this?
Founder Effect
What type of speciation is this?
Sympatric Speciation
What is a species?
No consensus, but most biologists would agree…
* Individuals descend from a common ancestral population
* Reproductive compatibility
* Genotypic and phenotypic cohesion
Three types of Biological Species Concept
Biological Species Concept
Morphological Species Concept
Ecological Species Concept
Characterizes species by their ability to interbreed to produce fertile offspring
Biological Species Concept
Characterizes species
by body shape and other morphological features
Morphological Species Concept
Characterizes species in terms of its ecological niche
Ecological Species Concept
True or False:
Horse, Donkey and Mule are disctinct species
False
Mule is not a species but a hybrid
True or False
Not all hybrids are infertile
True
Offspring produced by mating of individuals from two different species
Interspecific hybrid
True or False
Interspecific hybrids can sometimes be fertile and mate
with another hybrid or either of their parental species
True
