Phylogeny and modern taxonomy (03)

Question 1

How does evolution connect with phylogeny?

Answer 1

Phylogeny refers to the study of evolutionary relationships between and among specieies, (how similar are specific species, depending on the trait/time we are observing an organism)

for evolutionary relationships to happen, you must have evolution, where species change overtime into new spcieies, however continue to share ancestory. (All living things are descends from a common ancestor)

Question 2

How is phylogeny repersented?

Answer 2

Phylogenetic tree:
* Diagram that shows the evolutionary relationships
between different species
(How are different speicies related to each other through a common ancestory)

• Represents a hypothesis based on evidence (fossil
  record, morphology, embryological patterns of
  development, chromosomes, and macromolecules)
  Not 100% because based on physical and genetic charactersitics
• Allows us to see how organisms are related to each other

Question 3

Cladistics (How was phylogentic tree related to cladistics)

Answer 3

-> System of taxonomy
-> Classification of organisms

A system of taxonomy that reconstructs
phylogenies by inferring relationships based on
similarities

• Determines the sequence in which different groups
  of organisms evolved
• Focuses on a set of unique characteristics (derived
  traits or derived characters) found in a particular
  group of organisms.
• Based on the presence or absence of recently
  evolved traits

Question 4

What is a clade?
What is an outgroup?

Answer 4

Clade is a taxonomic group that includes a single common ancestor and all its descendants (living or extinct)

-> How species are divided up! (One cute in a lineage or a common ancestore should include all of tits decesndents or else it is not a clade)
-> A clatogram/phylogenic tree can have muliple clades (overlapping) (over many sizes)

Outgroup: a more distantly related group of organisms that
serves as a reference group when determining the
evolutionary relationships of the ingroup

Question 5

How to read a phylogenic tree?

Answer 5

Tips of the branches
represent the descendants of
that ancestor

As you move from the
root to the tips, you are
moving forward in time (down to up is from past to recent)

The root of the tree represents the ancestral lineage
* When a lineage splits (speciation), it is represented
as branching
* A single ancestral lineage gives rise to two or more
daughter lineages.

Question 6

There are differences between traditional taxonomy and modern taxonmy, what are differences?

Answer 6

Traditional: Based on morphology

Modern: Based on phylogeny (Evolution)

Question 7

Pros and cons of traditional taxonmy

Answer 7

Advantage:
- is simple and convenient

Disadvantages:
- Groups species primarily by morphological
characteristics. These groups are then arranged into a
set number of taxonomic ranks.
- Does not accurately estimate the degree of relatedness
between species.
- Mutations may lead to incorrect classification
- Different genetic materials may lead to similar physical
structures

Question 8

Pros and cons of modern taxonomy.

Answer 8

Advantages:
* Can uncover the evolutionary relatedness (phylogeny)
of organisms .
* The organisms are grouped into different-sized clades
that are not limited to a set number of taxonomic ranks.

Disadvantage:
* Uncovering evolutionary relatedness that may go back
millions of years—a task that may require detailed
analysis of both fossil and genetic evidence.