A3.2 Unity and diversity

Question 1

what is introgression and how is it achieved?

Answer 1

a process in which hybrids form over many generations with unequally distributed genetic information from each species.

It’s achieved through backcrossing: when a hybrid offspring breeds with a species of the original parents to produce offspring

Question 2

what is molecular systematics?

Answer 2

classifying organisms using molecular differences through protein and DNA sequences.

Question 3

what is phylogeny/ phylogenic tree and how does it differ from cladograms?

Answer 3

the study of the evolutionary past of a species. A phylogenetic tree indicates passage of time and the difference between species branching points, unlike cladograms.

Question 4

what do the x/y axes represent on a cladogram

Answer 4

the x axis is time from past to present
the y axis is quality from primitive traits to complex traits

Question 5

what is cladistics

Answer 5

cladistics is a system of classifying taxa based on characteristics that have evolved more recently (derived traits)

they research how close a common ancestor is through shared similarities between species, or gene sequencing.

Question 6

what are primitive and derived traits (on a cladogram)

Answer 6

• primitive traits are characteristics with more simple similar structure and function, and it means that they evolved early in traced history.
• derived traits are new and more recently evolved traits

Question 7

What is DNA hybridization?

Answer 7

measures the extent of similarities between dna sequences, more specifically, how far back a species split from a common anscestor

Question 8

DNA hybridization process

puzzle

Answer 8

One strand of DNA of one species and another of another species are fused together during enzymes. If the base pairs connect, there is a match, if they repell, there is not.

Question 9

what is a molecular clock?

Answer 9

uses quantitative biochemical data to to estimate and trace back the time of a speciation event.

Question 10

what is a node

Answer 10

place where speciation happened- shows common ancestor

Question 11

what is a sister group

Answer 11

group of closest relatives to the common ancestor

Question 12

what is an outgroup

Answer 12

less closely related to the others

Question 13

what is a root

Answer 13

the base in which the other species branch out

Question 14

what is the analysis of zones of DNA markers. E. g the nuclear ribosomal internal transcribed spacer?

Question 15

what are terminal branches?

Answer 15

tips of the branches

Question 16

what do the terms monophyletic and paraphyletic mean?

Answer 16

monophyletic
- a taxa defined by shared but unique characteristics of that group of species

paraphyletic
- taxa group defined by shared characteristics of common ancestor

Question 17

what is circumscription?

Answer 17

the process of placing taxa where they all show monophyletic groups, indicating that they all share a recent common ancestor

ALL GROUPS ARE MONOPHYLETIC

Question 18

what are DNA markers?what do they track?

Answer 18

used to track the inheritance of a nearby gene that has not yet been identified, but whose approximate location is known.

Question 19

what are the three domains

Answer 19

1. archaea (found in hydrothermal vents)
2. eukarya (all life other than archaea and bacteria)
3. eubacteria

Question 20

what separates archaea from the other domains specifically bacteria?

Answer 20

1. differences in their subunits of ribosomes
2. synthesising **methane **and hydrogen gas as a source of energy, which bacteria cant do
3. archaeas production of transcription and protein production from translation share more characteristics with what eukarya can do
4. physical features such as types of molecules that build its cell wall and membrane