Exam 2 Flashcards
Co-discoverer of natural selection?
Alfred Wallace
Wallace Effect?
natural selection contributes to speciation by promoting hybridization barrierss
Disjunct distributions?
when a taxon has 2 or more closely related groups that considerable separated from each other graphically
Allopatric speciation?
speciation by geographic isolation rivers, deserts or great distances
- often isolated in different environments
How does allopatric speciation occur?
occurs due to both adaption and genetic drift
Peripatric speciation?
- Special case of allopatric speciation
- small fraction of population isolated
- few isolated individuals carry rare alleles
How does peripatric speciation occur?
Genetic drift
Parapatric speciation?
- along environmental gradient
- individuals at ends adapted to fringe environments
- typically among species with limited dispersal
How does parapatric speciation occur?
mostly by adaptation to gradient
Sympatric Speciation?
-individuals occupy same geographic area, but still become reproductively isolated
How does sympatric speciation occur?
strong selection–> Adaptation
Dispersal?
taxa migrate from one region to another and establish new populations
- peripatric or allopatric
Vicariance?
Distribution becomes disjunct by the development of geographic barriers
Continental drift
- Proposed by Alfred Wegener
- Land masses seem to fit together, continental part of lithospheric plates float on basaltic crust on top of mountains
the likely principle direct or indirect source of vicariate events?
Contiental drift
Most important factor regulating fish distributions?
temperature
4 Major marine zoogeographic regions?
- Indo-West Pacific
- Western Atlantic
- Eastern Pacific
- Eastern Atlantic
Geminate species?
sister species from common ancestors whose distributions interrupted by rise of Panamanian isthmus
Primary Freshwater fishes?
confined to fresh water, evolutionary history in FW, no tolerance to high salinities
How many families of primary FW fishes?
85 families
Secondary FW fishes?
restricted to FW, may occasionally enter saltier waters
How many families of secondary FW fishes?
11 families
Peripheral FW fishes?
marine species with residence, that spend portion of life cycle in FW (i.e..e diadromous)
How many families of peripheral FW fishes?
30 families
Freshwater Zoogeographic regions? (6)
Nearctic Neotropical African Palearctic Oriental Australian
Nearctic?
- contains 14 families of primary FW fishes (950 species)
- 5 families of cyprinids, catostomids, percoids, centrarchids and ictalurics (350 species)
- Centrarchids-NA family only
10 Provinces of Nearctic?
Pacific Coastal Great Basin Colorado Rio Grande Mississippi Atlantic Coast Great Lakes/StLawrence Hudson Bay Arctic Mexican Transition
Pacific Coastal Province (Nearctic)
Yukon to mexico
- 132 species with 32 being endemic
Great Basin province (Nearctic)
150 internal drainages, very arid and salty (old Pleistocene lake)
- 50 species with 40 endemic
Colorado province (Nearctic)
32 species with 24 endemic
- many threatened by water diversions/extractions
Rio Grande Province (Nearctic)
along Rio Grande between US and Mexico
-154 species with 80 endemic species
Mississippi Province (Nearctic)
largest area drained by Missouri and Mississippi rivers
- contains the most species of Nearctic region
- 375 species with 130 endemic
- important during glacial refugee during glacial extent
Atlantic coast Province (nearctic)
rivers draining to Atlantic ocean
- high anadromy in north
- in south, high 2nd FW fishes
great Lakes/st Lawrence province (Nearctic)
largely developed from Mississippi drainage
- of glacial origin–> young species
- Depauperate, but high endemism
Hudson Bay Province (Nearctic)
Central canada
- 100 species
- Similar to Mississippi province
- high endemic minnows, trout, sculpins, pickerels and suckers
Arctic Province (Nearctic)
- northern rivers draining to Arctic Ocean
- 66 FW species with 33 diadromous, 14 primary FW and 7 secondary FW fishes
- share some species with Siberia
Mexican Transition
- Mosaic assemblage in several isolated xeric ponds, rivers, streams and lakes
- crater lakes and sink holes and wetlands
- up to 200 endemic species
Neotropical Region?
- has 10 defined provinces
- largest FW fish fauna worldwide
-32 families of Primary FW fishes
4475 described, 1550 undescribed species - many 2nd FW endemic fishes
Provinces of Neotropical Region? (10)
South Patagonia North Patagonia Trans Andean (south) Lake Titicaca Paranean South-East Brazilian East Brazilian Guianean-Amazonian North Venezuelan Trans Andean
South Patagonia Province (Neotropical)
12 species with 1 endemic
North Patagonia Province (neotropical)
23 species with 5 endemic
Trans Andean (south) Province (Neotropical)
19 species with 13 endemic
Lake Titicaca Province (Neotropical region)
32 species with 32 endemic
Paranean Province (Neotropical)
Argentine coastal river drainages
- 847 species with 517 being endemic
South-East Brazilian Province (Neotropical)
194 species with 90 being endemic
East Brazil Province (neotropical region)
131 species with 50 endemic
Guianean-Amazonian Province (Neotropical)
has most species of Neotropical region
- 2400 species with more than 2000 endemic
- many fishes here still undescribed
North Venezuelan Province (neotropical)
61 species with 9 endemic
Trans-Andean Province (neotropical region)
423 species with 326 endemic
Archaic freshwater fish distributions
6 primitive primary FW fishes
- Dipnoi (lungfishes)
- Potypteriforms (Bichirs)
- Polyondontidae (Paddlefishes)
- Lepisostidae (Gars)
- Amiidae(bowfins)
- Osteoglossomorpha (arapaima)
Dipnoi (lungfishes)
- on all 3 southern continents
- South American and African more derived than Australian (Australian is likely ancestor)
Potypteriforms (Bichirs)
in Africa, 2 genera and 10 species
- fossils found in Bolivia
Polyondontidae (Paddlefishes)
in Mississippi river, closest relatives in Yangtze River
Lepisostidae (Gars)
- found currently in NA, Central America and Cuba
- fossils in India and Europe
Amiidae(Bowfins)
- found only in NA but worldwide fossils except Australia
Osteoglossomorpha (Arapaima)
- found in North African, Amazon lowlands, Guianas, central America and in Queensland
Archaic freshwater fish dirstibutions evidence of long term ________?
Vicariance
Evolutionary history of recent freshwater fish distributions show tremendous ability for ____?___ and invading new open post glacial habitats.
Dispersal
Esocids (Pickerels and Pike)
- 2 families in NA and Eurasia
- Northern Pike on of most widely distributed fish
Percidae Perches and darters)
- included 175 species, 15 in Europe and 160 in NA
- wide distributions
Cichlids
-replace percids and centrarchid (confined to eastern NA) in southern continents FW habitats
Cyprinids (carp and goldfish)
large families
- 3200 species in NA, Africa, Europe, highest in Asia
Characids (tetras and piranhas)
- 10 to 15 families, 200 genera and 1000 species in South America
- 23 genera and 150 species in Africa
Siluriformes (catfishes)
- 34 families with 2000 species worldwide
- 1 FW family in NA, but 14 endemic families with more than 1200 species in SA
- 6 FW families with 400 species in Africa
- Several families in Asia
Palearctic Region
- Includes Europe and Asia
- 14 families of primary FW species
- 406 different hydrological basins
- 546 endemic species
Provinces of Palearctic region? (7)
1) Ponto-Caspian 2)Northern Europe
3) Western Europe
4) Central Europe
5) Central Peri-Mediterranean
6) Eastern Peri-Mediterranean
7) Iberian Peninsula
Ponto-Caspian Province (palearctic Region)
98 species with 26 endemic
Northern Europe (Palearctic region)
42 species, 4 endemic
Western Europe (Palearctic)
47 species, 3 endemic
Central Europe (Palearctic)
57 species, 1 endemic
Central Peri-Mediterranean Province (Palearctic region)
93 species, 60 endemic
Eastern Peri-Mediterranean Province (Palearctic)
62 species, 20 endemic
Iberian Peninsula (Palearctic)
50 species, 30 endemic
African region of FW fishes
- diverse fauna, 27 families of primary FW fishes and archaic species
- 3000 species, 280 genera
- home to many adapt radiations
- 300 species of minnows, 190 characins, 360 catfishes from 6 families
African FW provinces (10)
Maghreb Nilo-Sudan Upper Guinea Lower Guinea Congo East Coast Quanza Zambezi Southern Madagascar
Oriental Regio of FW fishes
- has 10 provinces
- India, Southern China, Southeast Asia, Philippines, East India, Borneo, Bali,…etc.
- 28 families of primary FW fishes, only 2 east of Wallace’s line
- endemic catfishes cypriniforms and many algae eaters
Genomics
concerned with the entire genomes of organisms, both nuclear (nDNA) and mitochondrial (mtDNA) DNA
Polyploidization-genome duplication (GD)
unequal exchange during recombination- chromosomes separation failure during meiosis
gonochoristic
genetically fated sex determined by chromosomes
populations
groups of interbreeding individuals that rarely exchange individuals with other such groups of the same species
F statistics
designed to asses departures from random mating among groups
Fst?
allele frequency difference among different populations assessed through population level heterozygosities
Gst
modification to account for haploid data
ϕst
incorporates allele frequency shifts and DNA sequence divergence between haplotype
Rst
more appropriate for micro satellites
Djost
more accurate and capable of reaching 1 most in situations where other indices cannot (maximum differentiation)
Nucleotide diversity ( π or Θπ )
measures average DNA sequence divergence
π=0 means?
all members are genetically identical at all nuceotides
π=1 means?
all members are genetically different at all nucleotides
Census Population Size (Nc)
total number of individuals regardless of age, sex or condition (no survival)
Effective Population Size (Ne)
number of individuals contribution to next generation- depends implicitly on age, sex or condition (implies fitness)
Levels of population structures?
Marine
Genetic diversity trends?
Marine>Anadromous>FW
Migratory Overlap
Where populations mix or during migrations at sea or offshore
Sex-biased Dispersal
gene flow disparity between genders
