chapter 20: the history of life Flashcards

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1
Q

How do biologists group organisms

A

they based them on shared/like characteristics

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2
Q

what are the characteristics that biologists group organisms by

A
  • fossil records
  • morphology
  • physiology
  • behaviour
  • embryological development
  • DNA or RNA sequences
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3
Q

what is systematics

A

reconstruction and study of evolutionary relationships

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4
Q

what is an important thing to note about tree of life diagrams

A

they are subjective as they are based on the authors beliefs

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5
Q

what is phylogeny

A

the hypothesis about relationships among taxonomic groups (is displayed through phylogenetic trees or cladograms)

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6
Q

what are the types of phylogenetic trees

A
  • rooted
  • unrooted
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7
Q

what is a rooted phylogenetic tree

A

uses single linage and represents a common ancestor at the base

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8
Q

what is a unrooted phylogenetic tree

A

a diagram that is used to show the relationship between species but does not display a common ancestor

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9
Q

what is the assumption that can be made when examining a rooted phylogenetic tree

A

in the common ancestor is not stated at the base then it is assumed to be Luka

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10
Q

what are the are the parts of a phylogenetic tree

A
  • taxon
  • clade
  • branch point (node)
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11
Q

in regards to phylogenetic tree what is a taxon

A

the group of organisms

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12
Q

in regards to phylogentic tree what is a claude

A

any branch or lineage that links taxons and branch points to the common ancestor

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13
Q

in regards to phylogenetic trees what is a branch point / node

A

any point where a single lineage splits into two seperate clades (any branch point / node is where the most recent common ancestor (MRCA) is found)

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14
Q

what are sister taxas

A

when two species are linked to the same closet branch points / nodes

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15
Q

what is taxnomy

A

a science of classifying organisms into taxas

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16
Q

what is the procedure of provided the name of a species through taxonomy

A

Genus (capitalozed) species name (lowercased)

17
Q

what determines a new species in the eyes of evolution

A

a singular shift in a nucleotide sequence

18
Q

How do systematists organize evolutionary relationship

A

they use diversity of evidence to determine between organisms in higher taxas

19
Q

what diversity evidence do systematists use to determine relationships between organisms

A
  • Form and function
  • behavioural
  • genetic characters
20
Q

what are the two options for similarities with different organisms

A
  • homologous character
  • analogous characters
21
Q

what are homologous characters

A

structures or characteristics that are similiarly structured with in different organisms but potentially have different uses

22
Q

what are analogous characters

A

structure or characterisitics that are similar in apperance due to functions or ecological constraints

23
Q

what is convergence

A

when characterisitics are shaped by similar ecological or evolutionary constraints (selection pressures)

  • this evolution is not a common ancestral trait
24
Q

What is evolutionary reversal

A

analogous characters that nay cause taxa to appear related when they are not related or distaintly related

  • ancestral traits are sometimes lost in descendants in one group
25
Q

what are molecular comparisons

A

when nucleotide sequences DNA and RNA provide use information on the relationships between organisms

26
Q

what are the limitations to molecular comparisons

A
  • when there are a smaller number of different nucleotides it can give the sense that it is a homologous characterisitc when they are not
  • certain mutations can cause sequencing to look unrelated when that is not the case
27
Q

Why do phylogenies matter

A

helps use understand the evolutionary relationships

28
Q

what is cladistics

A

the process of arganging taxas by homologous characters into clades (want to produce a cladogram where all clades are monophyletic)

29
Q

what are four things to remember about evolution

A
  • mutations are random
  • it takes multiple mutations to lead to a new trait
  • a trait may be benifical, harmful, or neutral
  • evolution changes a population over time ( indivduals do not evole)
30
Q

what is the rule of parsimony

A

choose the simplest cladogram with the fewest steps or event

31
Q

what is horizontal gene transfer

A

the transfer of genetic material between unrelated species

32
Q

what are two major points to remember about HGT

A
  • are more present in prokaryotes
  • mutations and HGT are the 2 main contributors to genetic variation `
33
Q

What are the methods of HGT

A
  • Transformation
  • transduction
  • conjugation
34
Q

What is transformation in regards to HGT

A

when naked DNA is taken up by bacteria

35
Q

what is transduction in regards to HGT

A

when genes are transferred by virus (attaches to the cell and transfers information to it)

36
Q

What is conjugation in regards to HGT

A

when genes transferred between two virus cells

37
Q

what is meant by the endosymbiotic theory in eukaryotes

A
  • mitochondria was engulfed by a different cell that was aerobic and was able to convert extra pyrvates in the cells into energy and the house cells would provide sugar from this mitochondrian process to occur (happened because of the access too oxygen within the host cell)
  • chloroplasts were also engulfed in this process