Cycle 8 Flashcards
Around _____ new species are discovered each year
18000
Sometimes we find evidence of new species that are already ______ (ex burrowing dinosaurs)
extinct
___ million describes species of eukaryotes that we know of
1.2
The fact that we keep discovering new species a year suggests that:
there are a lot of species out there that we don’t know about
Estimated that in terms of eukaryotic species globally is around ___ million (give or take 1.3 million)
8.7
_________ proposed universal common descent for all life on earth
Origins of Species
For every combination of species, there is a _____________ (MRCA)
most recent common ancestor
LUCA stands for
Last Universal Common Ancestor (LUCA)
LUCA was ____ the first living thing
NOT
Was or Was not the only thing living at the time
WAS NOT the only thing living at the same time but those individuals did not go off and split off
Would LUCA have ancestors of their own?
YES (Those individuals are also common ancestors but not the most recent)
Branching points on the Tree of Life -> rendezvous points (______)
speciations
If we go back far enough in time. Any ___ individuals will share a common ancestor
two
At some point, ________. Some of your ancestors on your mom’s side are also ancestors on your dad’s side.
pedigrees collapse
“Rendezvous Zero” _____ of all humans
MRCA
Rendezvous 4: Gibbons
MRCA of:
all apes
How long ago did the most recent common ancestor of all modern humans live?
Around 3000 years (100 generations)
T/F Almost every human on earth is your 50th cousin or closer
TRUE
Rendezvous 1: Chimps and bonobos
Are Chimps and bonobos more closely related to each other or us?
Chimps and bonobos are more closely related to each other than us
We as humans are _____ as closely related to chimps and bonobos
equally
Rendezvous 2: Gorillas
The next closest evolutionary cousins are gorillas
MRCA of:
African great apes
Rendezvous 3: Orang utangs
Great apes but, they don’t live in Africa, they live in Asia
MRCA of:
of all great apes
________ mass extinction, 65 mya
End-Cretaceous
“If we are descended from chimpanzees, why are there still chimpanzees around?”
FALSE: we are not descended from chimps, the most common ancestor that lived around 5-6 million years ago was not a chimpanzee, bonobos or humans
We all evolved
There are things that we call monkeys like old-world money that are more closely related to ________ compared to new-world monkeys
us (no monkeys like apes)
Rendezvous 7: Tarsiers (5 species)
Rendezvous 8: Lemurs and Lorises (50 species)
MRCA of: _______ (63 million years ago)
all primates
Rendezvous 5,6: Old World and New World monkeys
Around 25 million years ago we met up with 100 species of what we call old-world monkeys
The problem is:
The problem with the term monkey is that it is a term that does not reflect evolutionary relationships very well
Rendezvous 10: Rodents and rabbits
____ are famous for forming new species
Rodents
Rendezvous 11: Laurasiatheres
Bats, Insectivora, Carnivora, perrisodacltys
Spent most of their time on the northern subcontinent of _______
Laurasia
Rendezvous 18-22: Lungfish; Coeleacnath; Ray-finned fish; Sharks; Jawless fish
ISSUE: _______
MRCA of all vertebrates 530 mya
These ‘fish” are no more closely related to each other than they are to us
Other vertebrates
Rendezvous 17: Amphibians
MRCA of:
all tetrapod’s 340 mya
endezvous 14: Marsupials
Provide cool examples of ________
Not similar to moles because they’re close relatives, but instead we can see how features are similar due to their environment
convergent evolution
Some similarities reflect shared ancestors: other similarities reflect:
convergence
Rendezvous 15: Monotremes
Egg laying mammals
MRCA of:
all mammals
Rendezvous 16: Reptiles
Also, not the best name because:
There are things that we call reptiles like lizards or snakes that are more closely related to birds compared to other reptiles like turtles
Rendezvous 26: ______
Over 1 million described species
Great at forming species
Protosomes
Rendezvous 39: ______
Before Last one: back to LUCA
Bacteria
Rendezvous 38: _____
Adaptions to extreme environments
Archae
Rendezvous 34, 35, 36: Fungi, Amoebozans, Plants
________ has evolved separately in animals, plants, fungi, and ameoenpzpans
Multi-cellularity
We can trace our ancestry back to LUCA in just ___ steps
39
All life on earth related through:
common descent
T/F It matters what we call species
TRUE
Why is it important to define how we identify species in the sense of conservation?
ESA (in the USA) SARA (in Canada) and IUCN (global) provide stronger legal protection for conserving endangered species than for conserving endangered subspecies or populations
T/F It matters how we define and identify species
TRUE
Who said: “No one definition (of species) has as yet satisfied all naturalists; yet every naturalist knows vaguely what (they) mean when (they speak of a species.”
Darwin
____________
Species = a distinct cluster in phenotypic space. No intermediates or overlap with other clusters
Morphological Species Concept
Even though differences in skin color for humans, there are so many ________
intermediates
Flaws of biological species concept
Flaws:
Black bear, rare has white fur (mother and colour look different, but not true)
Sexual dimorphism (female and male look different, no intermediates)
Appearance varies through lifetime (like tadpoles to frogs)
Discrete/discontinuous variation in morphology presence problems for this concept
There can be groups of organisms that look similar but they can tell each other apart (makes more sense to consider them two different species)
Over __ species concepts have been proposed
50
T/F is a universal species concept
False: Still no universal species concept
_________ Species Concept: Reproocutvie isolation and shared gene pool
Biological
Two conditions for biological species concept
Freely interbreed under natural conditions
Produce viable, fertile offspring
For Biological Species Concept:
Species = an ______ or potentially _______ group of individuals, reproductively isolated from other such groups
interbreeding
Flaws of Biological species concept: (4)
-Cannot use the concept on organisms that reproduce entirely asexually
-We find potential new species, but they are not alive (cannot tell who mates with who with just fossils)
-Ring species
At most points along the ring, few populations are willing to mate with others, but at one point in the ring, individuals are not willing to mate with another group
Depending on where you go to study mating interactions, you will
get different conclusions
-Also, issue if two populations are fully allopatric
If their geographic range doesn’t overlap with each other
Geographically separated, so will never know if would naturally mate
Flaws: of ecological species concept
Ex: Frogs, grow up aquatic but later in life they live on land and breathe through lungs (very different ecology)
______ Species Concept
Species = a group of organisms that are adapted to a particular set of resources (niche) in the environment
Ecological
______ Species Concept
Species = group of population with a recent evolutionary history
Phylogenetic
The ____ group of populations that are all more closely related to each other than to anything else
smallest
Baltimore and Bullock’s orioles look different, and they are not each other’s closest relatives. They interbreed where their ranges overlap, and produce hybrid offspring of normal fitness. Which of the species concepts below would consider these birds as belonging to the same species?
Moprholcial
Biological
Phylogenetic
Biological
Flaws: of phylogenetic species concept
Have to work out evolutionary relationships/have to know the phylogeny of the organisms
Need a lot of previous knowledge
The outcome of secondary contact (depends on: )
when it happens
Allopatric speciation (4 steps)
1) Single population
2) Becomes separated (ex river, highway, mountain)
3) Populations diverge (ex difference in selection pressure or genetic drift)
The longer they are separated, the more they diverge
All that is needed for speciation to happen
4) SOMETIMES: Secondary contact
______ contact
Populations are back in contact
Secondary
Secondary contact is or is not needed for speciation
is not
May resume interbreeding (_____) - if secondary contact happens early in the speciation process
fusion
______ (reproductive barriers exist after fertilization, preventing hybrid offspring from surviving or reproducing)
Postzygotic
_______(the separation of different species to keep them from creating offspring by preventing the gates from forming a zygote)
Prezygotic
______: selection favors the evolution of prezygotic isolation
Reinforcement
Or, may become partly or fully reproductively isolated (if secondary contact happens ____)
later
If populations come back into contact, and if postzygotic isolation has already occurred, individuals who don’t _____ are favored
hybridize
Secondary contact can result in ___ (undoes isolation), OR ____ (accelerates isolation), depending on when it occurs
fusion
reinforcement
