Module 4: Classification and Evolution(Phylogeny & Evidence for Evolution) Flashcards
Phylogeny is the name given to …
Therefore , phylogenetics is the study of …
A phylogenetic tree is a diagram used to represent …
the evolutionary relationships between organisms
the evolutionary history of groups of organisms
the evolutionary relationships between organisms
What do phylogenetic trees show ?
In phylogenetic trees , state where the earliest species are found and where the most recent species are found
that different species have evolved from a common ancestor
Earliest-at the base of the tree
Most recent-at the tips of the branches
Advantages of phylogenetic classification …
Phylogeny can be done without reference to what?
the Linnean classification system
What does classification use knowledge of phylogeny for?
to confirm the classification groups are correct or causes them to be changed
State and explain 2 other advantages of phylogenetic classification
(HINT: point 2-more of a weakness of the Linnean system)
-it produces a continuous tree whereas classification requires discrete taxonomical groups
this means scientists aren’t forced to put organisms into groups they don’t fully belong/fit in
-the hierarchal nature of the Linnean classification system can be misleading as it implies that different groups within the same rank are equivalent when they aren’t
Make 4 initial points about evolution
(make a point defining what evolution is)
evolution-theory that describes the ways in which organisms change or evolve over many years as a result of natural selection
-organisms that are best suited to their environment are more likely to survive and reproduce , passing their characteristics onto their offspring
-over time a species gradually changes to have a more advantageous phenotype for the environment it lives in
-advantageous characteristics are passed from one generation to the next by genes in DNA molecules
Name another scientist who was working on their own theory of evolution
Make another point about the work of these two scientists
Alfred Wallace
-their theories were so similar that they proposed a theory of evolution through a joint presentation of two scientific papers to the Linnean Society of London on 1st July 1858
Make 3 points about how fossil records work and then provide evidence for evolution
How do fossils form?
fossils-form when animal and plant remains are preserved in rocks
over long periods of time , sediment is deposited on the earth to form layers (strata) of rock
these strata correspond to different geological eras , the most recent being on the top
the fossils found in the different rock strata are different , showing how organisms have gradually changed over time
Give the first 2 pieces of evidence provided by the fossil record
1)fossils of simplest organisms such as bacteria are found in the oldest rocks and fossils of more complex organisms are found in more recent rocks , supporting the evolutionary theory that simple forms gradually evolved over long periods of time into more complex organisms
2)the sequence in which organisms are found matches their ecological links to eachother (plants found before animal ones , animals need plants to survive)
Give the other 2 pieces of evidence provided by fossil record
3)by studying anatomical similarities between fossils of organisms , scientists can see how closely related organisms have evolved from the same ancestor
4) fossils allow relationships between extinct and living organisms to be investigated
Because fossil record is incomplete due to some organisms being soft bodied and therefore decomposing before fossilising , scientists use what other source of evidence to determine evolutionary relationships?
Explain what this is briefly
comparative anatomy
the study of similarities and differences in the anatomy of different living species
Define what a homologous structure is
The presence of homologous structures provides evidence for what type of evolution and why?
a structure that appears superficially different in different organisms but has the same underlying structure
divergent evolution , because it shows how from a common ancestor , different species have evolved each with a different set of adaptive features
Comparative biochemistry is the study of what?
What is a neutral substitution?
Do these substitutions happen regularly?
similarities and differences in the proteins/other molecules that control life processes in different organisms
a change in a molecules structure which occurs outside of the molecules functioning region , therefore the change has no effect on the molecules functioning
yes
How can scientists estimate the point at which two species shared a common ancestor?
Species that are closely related show more similarities in terms of what ? (2)
by plotting the number of differences in molecular sequences of a particular molecule against the rate at which the molecule undergoes neutral base pair substitutions
in terms of their DNA and proteins
