A3.2 classification and cladistics

Question 1

need for classification of organisms

Answer 1

-there is immense diversity of species, after classification, a broader range is study is allowed
-we can discover ancestries and which species are more closely related

Question 2

difficulties of classifying organisms into traditional hierarchy of taxa

Answer 2

-it does not always correspond to the patterns of divergence generated by evolution
-classifying on morphology is subjective
-system is ranked, each category is placed in another, moving is difficulty
-hybridization common in plants and cloning plants can be considered new species
-biological systems are more complicated then saying species are the basic unit of classification

Question 3

steps of discovery of kingdoms

Answer 3

1- anamalia and plantae
2-anamailia, plantae and protista
3- anamalia plantae protista and monera
4-anamalia plantae protista monera and fungi

evidence due to rRNA showed diversity in prokaryotes and split into two kingdoms.

4- anamalia plantae protista, bacteria archea, fungi

Question 4

introgression

Answer 4

Is the transfer of genetic material between species following hybridization and backcrossing to the parental species

-process by which hybrids form over many generations but has an unequal contribution of genetic material from each specie due to the hybrid backcrossing and mating with an original parent species to form offspring.

-after generations of organisms resulting from introgression by backcrossing, may only have 5-10% of original species genus, accounts for variety of a species.

Question 5

the three domains and the features of each

Answer 5

ARCHEA
-no nuclear membrane
-ancient
-extremists
-RNA and and biochemistry distinct from bacteria
EUBACTERIA
-no nuclear membrane
EUKARYOTA
-domain which you find all life
-nuclear membrane
-membrane bound organelles

Question 6

phylogeny and how it is represented and how it is found

Answer 6

-phylogeny is the study of an evolutionary past of a specie
-shown by phylogenetic tree-which shows the relationship between many species and which common ancestor they developed from

use fossil, molecular, and genetic data systematics to infer evolutionary relationships

Question 7

structure of phylogenetic tree

Answer 7

-A phylogenetic tree represents a hypothesis about evolutionary relationships
-Each branch point represents the divergence of two species
-Sister taxa are groups that share an immediate common ancestor

Question 8

what we cant learn from phylogenetic trees

Answer 8

-Phylogenetic trees show patterns of descent, not phenotypic similarity
-do not indicate when species evolved or how much change occurred in a lineage
-It should not be assumed that a taxon evolved from the taxon next to it

Question 9

cladistics
clades
cladograms

Answer 9

-cladistics= system of classification, studying groups of organisms by common descent, based on characterizes that have evolved more recently
clades= a group of species that include a common ancestor and all its descents
-cladogram=show the probable sequence of divergence and revolutionary history

Question 10

structures of a cladogram

Answer 10

-root=base from which other species branch out
-node=branch points where speciation occurred, and the relative position of common ancestor
-sister group=group of closely related relatives
-Outgroup= group that is less closely related to others in a cladogram
-clade= a group of organisms that evolved from a common ancestor (adjacent after node)
-terminal branch= tips of the diagram representing most recently evolved organism

Question 11

primitive traits
derived traits

Answer 11

primitive traits= characteristics that has a similar structure and function and evolved in early history of organisms
derived traits= characteristics that have similar structure and function, but have evolved more recently, in the form of modification of previous traits

Question 12

homology
analogy

Answer 12

homology = similarity due to shared ancestry
analogy=similarity due to convergent evolution

Question 13

molecular clocks

Answer 13

-consistent rates at which mutations occur in DNA, this shows how much time has passed since species diverged from each other

-estimating evolutionary events due to the regions of DNA that appear to evolve at constant rates

-it is possible to count the number of differences between the same homologous molecules of related species using DNA HYBRIDIZATION

Question 14

dna hybridization

Answer 14

-way in counting number of differences

-taking one strand of DNA from species A, and a homologous strand from species B, which are fused together using enzymes
-where base pairs connect there is a match, where base pairs repel there is a difference

-the differences indicate the splits of characteristics and is an estimation of speciation events

Question 15

paraphyletic

Answer 15

term used to describe species on separate branches

Question 16

reasons for separation of prokaryotes

Answer 16

-differences in subunits of their ribosomes
-archaea carries out metabolic reactions no bacteria can perform
-archaea’s way of transcription and translation share more similar characteristics with eukaryotes then bacteria
-some physical features of archaea are different from bacteria
-difference in molecular cell wall and membrane