a3.2 (classification & cladistics)

Question 1

what does taxonomy focus on?

Answer 1

the classification of living things

Question 2

benefits of taxonomy x3

Answer 2

communication of biological info between scientists

predictions of characteristics - if characteristics of a taxonomic group are known, then information about individual species in the group is also known

species in the same group probably share a common ancestor, indicating info about how species evolved

Question 3

research difficulties using a hierarchical structure!!!!!!
e.g. cladistics and paradigm shift

Answer 3

-

Question 4

define introgession

Answer 4

the process of hybrid formation over many generations

Question 5

molecular systematics classified organisms using what?

Answer 5

molecular differences in their protein sequences and DNA

Question 6

phylogeny is the study of what?

Answer 6

the evolutionary history and relationships among species or groups of species

Question 7

what do phylogenetic trees/cladograms visually represent?

Answer 7

how different organisms are related to each other through common ancestry, showing how species diverged from common ancestors over time

Question 8

define clades. in phylogenetics what are they used to describe?

Answer 8

a group of organisms that includes a single common ancestor and all of its descendants

in phylogenetics, clades are used to describe evolutionary relationships and to organize species based on their shared ancestry

Question 9

define monophyletic group

Answer 9

it consists of an ancestor and all of its descendants

Question 10

define paraphyletic groups

Answer 10

includes some but not all descendants of a common ancestor

Question 11

define polyphyletic groups

Answer 11

defined by characteristics not present in a common ancestor

Question 12

how is a cladogram stuctured

Answer 12

each branch point, or node, on the cladogram represents a common ancestor, and the branches represent the evolutionary lineages that have diverged from that ancestor

Question 13

how does cladistics organize taxa (kingdom, phylum, class, etc.)?

Answer 13

based on their evolutionary relationships (instead of grouping organisms solely by shared traits or overall similarities, cladistics focuses on common ancestry)

Question 14

define primitive traits

Answer 14

characteristics that evolved early in the history of the organisms being studied

Question 15

define derived traits

Answer 15

characteristics that have similar structure/function but evolved more recently

Question 16

watch a video on molecular clocks!!!!!

Answer 16

-

Question 17

define molecular clock

Answer 17

a method used to estimate the timing of evolutionary events and the rate of genetic change over time

Question 18

watch a video on cladograms!!!!

Answer 18

-

Question 19

6 features of a cladogram (& definition)

Answer 19

Branches: Represent evolutionary lineages or taxa. Each branch illustrates the path of evolution from a common ancestor.

Nodes: Points where branches diverge. Each node represents a common ancestor from which the taxa or lineages originated.

Root: The base of the cladogram, representing the most recent common ancestor of all the taxa included in the diagram.

Terminal Taxa (or Leaves): The endpoints of the branches, representing the taxa or species being analyzed. They are found at the outer edges of the cladogram.

Branching Order: The sequence in which branches split, indicating the relative timing of evolutionary divergences. Closer branches indicate more recent common ancestry.

Clade: A group of taxa that includes an ancestor and all its descendants. Each clade is represented by a branch or a set of branches stemming from a single node.

Question 20

define parismony

Answer 20

a principle used to determine the simplest cladogram with the fewest changes or evolutionary steps, assuming that the least complex explanation is the most likely

Question 21

4 steps to analyzing cladistics to generate a phylogeny tree

Answer 21

1:select a gene or protein common to a range of selected organisms

2:copy the molecular sequence (DNA or amino acid) for each of the selected organisms. use online databases such to identify relevant DNA or amino acid sequences. before each sequence, designate a species name preceded by a forward arrow

3:run a multiple alignments to compare molecular sequences (DNA or amino acid). closely related species are expected to have a higher degree of similarity in their molecular sequence

4:generate a phylogeny tree (cladogram) from multiple alignment data

Question 22

3 domains of life

Answer 22

eukarya– eukaryotic organisms that contain a membrane-bound nucleus

archaea– prokaryotic cells lacking a nucleus and consist of the extremophiles

bacteria– prokaryotic cells lacking a nucleus and consist of the common pathogenic forms

Question 23

what is the evidence that supports archaea being a domain of life? x4

Answer 23

16s rRNA differs when compared to bacterial 16s rRNA

archaea carry out metabolic reactions that bacteria can’t perform (these metabolic reactions allow archaea to often live in extreme environments)

archaea transcription and translation are more similar to eukaryotes than bacteria

archaea cell membrane and cell wall materials are different than bacteria

Question 24

linnaeus’s system of classification x8

Answer 24

domain
kingdom
phylum
class
order
family
genus
species

Question 25

what animal protein is used in molecular clocks?

Answer 25

cytochrome c

Question 26

example of forming of new families based on DNA evidence, x2 things that happened

Answer 26

figwort being split into 5 different clades

several genera were moved to 3 other families