Patterns of evolution? Flashcards
What divergence or divergent evolution is?
Divergent evolution is when two or more species are formed from a common ancestor.
What kind of speciation leads to divergent evolution?
Allopatric Speciation leads to divergent evolution as populations are exposed to different environments and therefore different selection pressures. Overtime the populations will be so different that they will be considered distinct species.
What is the definition of homologous structures?
Homologous structures are features which are similar in structure and origin but have different functions.
How are homologous structures related to divergent evolution?
Homologous structures are identifiers that the species have a common ancestor and therefore experienced divergent evolution.
What is convergent evolution?
Convergent evolution involves two totally different species forming similar traits.
What is the definition of analogous structures?
Analogous structures are features in a species which have different evolutionary origins but similar functions.
How are analogous structures related to convergent evolution?
Analogous structures are identifiers that the species may be experiencing convergent evolution.
What is co-evolution?
Co-evolution is where the evolutionary changes in one species acts as a selection pressure for another resulting in evolutionary changes in another species.
What are the types of relationships that may Involve co-evolution?
Mutualism, Paratism, Predation, Competition.
What is it meant by the rate of evolution?
The rate at which evolution occurs.
What is gradualism?
The idea of gradualism says that the accumulation of continuous small changes in the gene pool over long periods of time results in gradual transitions.
What is punctuated equilibrium?
Speciation where there have been long periods of little or no change followed by a sudden burst of rapid speciation.
What is the difference between gradualism and punctuated equilibrium in terms of the rate of evolution?
Gradualism occurs at a slow rate of evolution and punctuated equilibrium occurs at a fast rate of evolution.
What is adaptive radiation?
Adaptive radiation involves the rapid evolution of a number of species from a single common ancestor.
(Divergent evolution but sped up)
What does the term “Anagenesis” mean?
The evolution within a lineage. A result of rapid evolution of the ancestral form without speciation taking place. (Changes within a species)
What does the term “Biogeography” mean?
A branch of biology which investigates the geographical distribution of of plant and animals as evidence of evolution.
What does the term “Cladogenesis” mean?
Evolution that results in the splitting of a lineage. This is where the parent species splits into at least two distinct species.
What is convergence?
Unrelated species evolve similar characteristics under similar environmental selection pressures.
What is the Fossil Record?
The preserved remains of long dead organisms that can be studied to show how evolution has changed over time.
What is the “Mitochondrial DNA (mtDNA)” ?
Unaffected by recombination, it is inherited from mother to offspring largely unchanged.
What are molecular clocks?
It is the estimation of the timing of evolutionary events based on the known (Contant) rate of mutations in certain genes.
What does “Stratigraphy” mean?
The order and relative position of strata and their relationship to the geological timescale.
What are Vestigial Structures?
An unused feature that is a historical remnant of a structure that served a purpose in the organisms ancestor. (For example we have teeth which are used to consume grass and the intestine to absorb this although we do not eat grass anymore)
What is the Y chromosome and its purpose?
It’s passed on from father to son (Like the mtDNA) relatively unchanged and can be used to determine the relativeness of populations.
