evolution and diveristy Flashcards
(90 cards)
1
Q
what is a cladogram
A
an evolutionary tree that shows the recency of common ancestry
2
Q
what is a dendrogram?
A
an evolutionary tree that adds times of divergence
3
Q
what is a phylogram?
A
an evolutionary tree that shows the amount of evolution
4
Q
what is autapomorphy?
A
distinctive feature / chracteristic found in a single group and not in others
5
Q
what is plesiomorphy?
A
primitive character shared by two or more species
6
Q
what is convergence?
A
unrelated organisms share the same feature
7
Q
what is synapomorphy?
A
- shared derived character
- can be evidence for a relationship
- needed to build trees
8
Q
ingroup
A
groups to which individuals belong / identify
9
Q
outgroup
A
groups to which individiduals do not belong or identify
10
Q
how to identify derived features?
A
if they are not shared = derived
11
Q
what is parsimony?
A
- occurs when there are two possible trees
- successful one is the one with the fewest number of steps / evolutionary changes
12
Q
classification of taxnomic groups
A
domain
kingdom
phylum
class
order
family
genus
species
13
Q
paraphyletic groups
A
- groups grouped by the absence of something
- or share something that is primitive
- originate from same ancestor but does not involve all descendents from that ancestor
14
Q
monophyly
A
- evolved just once
- descendent from a single ancestor
15
Q
paraphyly
A
- evolved more than once
- unrelated organisms decended from more than one ancestor
16
Q
what is the stem group?
A
set of extinct taxa
17
Q
what is the crown group?
A
all living members of the paraphyletic assemblage
18
Q
clades
A
- have real evolutionary gaps
- group of organsims with a single ancestor
- cladistic classification comprises only of monophyletic groups
19
Q
grades
A
- have artificial gaps
- united by a level of morphological or physiological complexity
- similar due to adaptation or convergence
20
Q
what is the molecular clock hypothesis?
A
the amont of evolutionary change in a given gene across different lineages is approximately constant over time
- depends on the gene: some evolve faster than others
21
Q
molecular clocks
A
- measure evolutionary change over time at a molecular level
- based on the theory that spontaneous mutations occur
22
Q
when does saturation occur?
A
when sequence divergence is not linear over time
23
Q
solutions to saturation
A
- try another gene
- try and model DNA sequence evolution
- use other kinds of molecular data
24
Q
types of genetic substitutions
A
- transitions e.g. A to G or C to T
- transversions (rare) e.g. A to C or G to T
25
evidence that we can infer phylogeny
- different genes for the same species (usually) produce the same tree
- compare inferred tree to "known" phylogeny
- computer simulations
26
long branch attraction theory
when 2 very different taxa or clades with long branch lengths are inferred as each others closest relative due to convergent evolution of a given character
27
altruism
when an individuals behaviour benefits other at a cost to itself
28
altruism in bees
- 50% chance of genes being passed onto next gen even if die due to siblings
- help colony at potential cost of itself
29
eusociality
tendency for inidividuals to reduce their own lifetime reproductive potential to raise the offspring of others
30
gradualism
evolution as a slow steady process where organisms change and develop slowly over time
31
punctuated equilibrium
- long periods of no evolutionary change followed by rapid periods of change
- intermediate forms rare
32
species richness
number of different species in a community
33
species diversity
- measures how two species differ
- relative abundance the two species
- identifies any patterns and functional importance
34
how can we measure / interpret genetic variation?
- allele / genotype frequency data -> how distributed in terms of abundance
- DNA sequence data via phylogenic trees
- DNA sequence data vie population genetics analyses
35
allozymes
used to identify genetic variation within a population or species by running protein through a charged matrix
- enzyme phenotypes rather than genotypes
36
gene flow
- movement of genes in / out of a population
- spread of alleles by interbreeding
37
population structure
can be a barrier to gene flow
38
allele frequencies
- homogenized across populations by gene flow
- differentiated by population structure
39
neutral variation
- multiple alleles present at a given genetic locus because those alleles are not distinguished by natural selection
40
genetic drift
change in frequency of an existing gene variant in pop due to random chance
41
microsatellites
short repeated sequeces of DNA in a genome
lots of genetic variation due to repeats frequently added or lost
42
haplotypes
individual alleles
set of DNA variants along a single chromosome that tend to be inherited together
43
polymorphism
presence of 2 or more variant forms of a specific DNA sequence
44
DNA barcoding
using DNA sequences from a certain region on the genome to identify species
45
operational taxonomic units
defining distinct lingeages based on arbitrary threshold of genetic distance
46
taxonomy
discovery, description and identification of species
47
systematics
relationships among species
48
what is needed for species descriptions?
- need to know which species already exist first
- unique name
- diagnosis for recognizing
- detailed anatomical description
- type specimen
49
how many species are there?
- birds & mammals: 2x as many tropic species as temperate species
- most species are insects (2/3 outside tropics)
- around 3-5 million species
50
what is a functional trait?
a phenotype or characteristic of an organism (defined by its niche) that defines its fitness and could affect its survival
- e.g. morphology, development, behaviour...
51
what do different morphological characteristics indicate?
that the species perform varied functions in the ecosystem with high functional diversity
52
functional diversity
surrounds the range of things that organisms do in ecosystems and communities
more functional diveristy = more stable ecosystem
53
functional redundancy
species loss by compensating with other species that have similar functions
54
energy flow of the foodchain
is an ecosystem function that sustains myriad animal consumers
55
ecosystem function
capacity of natural processes and components to provide goods and services that satisfy human needs, either directly or indirectly
56
ecosystem process
- the physical, chemical, and biological processes that link organisms and their environment
- primary production, respiration, energy, carbon and nutrient flow through food webs, reproduction, and decomposition
57
primary productivity
growth of plant species in the ecosystem level
a fundamental metric of ecosystem function
58
the complementarity hypothesis
- the more species in a community, the greater the probability that these will belong to different functional groups.
- this increases the complementary resource-use which leads to more productivity
59
the facilitation hypothesis
some species have a positive effect on the ecosystem role played by other species
60
why is ecosystem function enhanced when we have more species?
benefit from each other
61
sampling effect
result of increased probability that a productive species will be found in a community with many species
62
the selection effect hypothesis
the more species present in an assemblage, the higher the likelihood that a particular productive or efficient species will be present in the community
-> species rich communities more productive bc more likely to contain an essentially productive species
63
molecular diversity
connectivity and impacts of habitat fragmentation important to understand threats that decrease population size
64
taxonomic diversity
how things are names could affect conservation priorities
65
functional diversity
ecosystems vs single species management
- carnivores need herbivores to eat that need plants to eat.....
66
what are conservation priorities based on?
phylogenetic distinctiveness
- e.g. do certain endemic species lack close relatives?
67
what factors affect genetic variation?
- population structure and demography e.g barriers to gene flow & consequences to habitat fragmentation
- mating systems e.g. inbreeding
- selection e.g. adapt to changing conditions
68
inbreeding depression
reduction in fitness of inbred vs outbred individuals
69
deleterious recessive mutations
hidden with outbreeding but exposed after inbreeding due to increased homozygosity
70
taxonomy
the discovery and description of species
71
systematics
the inference of relationships among species
72
reproductive assurance
more potential mating partners if dont have to avoid relatives
73
purging
survivors have removed negative mutations
74
outbreeding depression
happens when crosses between two genetically distant groups or populations result in a reduction of fitness
- e.g. if you mix the northern and southern african wild dog populations -> due to large genetic differences
75
biological species concept
- defines a species taxon as a group of organisms that can successfully interbreed and produce fertile offspring.
- groups of actually or potentially inbreeding populations
76
ecological species concept
- set of organisms adapted to a certain set of resources (niche) in the environment
77
evolutionary significant units
number of genetically distinct populations deserving seperate protection
78
keystone species
an organism that helps hold the system together.
79
how to calculate the amount of evolution?
rate x time
(can be slow rate x long time or fast rate x short time)
80
types of evolutionary changes
- constituous change
- episodic change
81
how can we get evolutionary dates?
- fossils
- biogeogaphy
- hosts and parasites
82
fossils and evolutionary dates
- they provide an estimate of the minimum age only
- fossils from sister groups must be the same age
- fossils and molecular data can show the molecular divergence
83
cospeciation and evolutionary dates
- occurs when interacting groups, such as hosts and parasites, speciate in tandem, generating congruent phylogenies
- can help date things surrounding the host
- assume parasites have cospeciated not switched hosts
84
founder event speciation
acestral species -> small popularion founded by a few individuals -> small population becomes genetically isolated from ancestral species
85
advantage of molecular evolution
can compare rates using same units
86
speciational change evolution
if evolutionary changes happen over species
87
gradual change evolution
evolutionary changes scattered throughout the tree
88
biogeographical barriers
- rivers
- islands
- drowing (of land)
- disjunctions
- fault lines
- vicariance
89
disjunctions
when two or more groups that are related are considerably separated from each other geographically
90
vicariance
the study of repeated patterns of disjunct distributions within many members of a biota that may be explained by vicariance (or splitting) and other historical events
