Find study materials for any course. Check these out:
Browse by school
Make your own
To login with Google, please enable popups
To login with Google, please enable popups
Don’t have an account?
To signup with Google, please enable popups
To signup with Google, please enable popups
Sign up withor
Ecological/ Habitat Isolation
– Temporal Isolation
– Ethological / BehavioralIsolation
– Mechanical Isolation
– Gametic Mortality orIncompatibility
– F1 Inviability:
– F1 Sterility:
– Hybrid Breakdown:
Ex. TigerX Lion = Liger/Tigon (reduced fertility/infertile)
• GreyWolf X Coyote = Red Wolf (not sterile/variable fertility)
• Hamadryas and Anubis baboonsare “sub-species”
• Rangesoverlap around Awash River in Ethiopia
• Society is patriarchal(dominated by males) and patrilineal
• Males stay in natal group andfemales move around
• Males herd females creatingharems of unrelated individuals
• Dominantmales tend to be related
Societyis matriarchal (dominated by females)
• Females stay in natal group,and males move around.
• Groups of related femalessupport each other
• Matingis promiscuous (female choice)
Hamadryasmales born to Anubis females
• Anubis females born toHamadryas females
• Reducedfitness because of behavior
Oftenform in small populations
– Why? Genetic drift
• Effectof new mutations in a small population vs. large population
• Mutation will increasevariation between species, as it occurs independently in isolated populations(with no gene flow)
• Genetic drift will alterallele frequencies after isolation
• Naturalselection will change allele frequencies after isolation, and may be differentfor the two populations (if inhabit different environments).
TEMPO ANDMODE OF EVOLUTION
There issome debate surrounding how quickly macroevolution occurs, and whether the rateof evolution is steady or irregular.
Slow andsteady accumulation of variation. Predicts smooth transition.
• Mostly“stasis,” with short rapid changes
1) Bigger is not always better
2) Newer is not always better
– Age of the structure has nobearing on its usefulness. – Example: upright walkingdeveloped >, 5 digits developed several hundred mya, but both areequally imperative to the success of humans.
3)Natural selection does not always work. (We are more likely to go extinct thanto adapt.)
4) NoOrthogenesis. (Evolution is not headed in a specific direction)
5)Natural selection does not always produce perfect structures. Just has to be “good enough.”
6) Notall structures are adaptive. Some are by-product of other biological processes(the chin), and others may have once had a function but no longer do(appendix).
7)Current structures do not always reflect initial adaptations. – Structures with givenfunctions now may not have evolved specifically for that function.
STUDYINGTHE FOSSIL RECORD
Mustfirst determine the age of different fossil specimens
• Thiscan be done in two ways –Relative Dating –Chronometric Dating
The studyof what happens to plants and animals after they die
• Helps us understand thefossil record
– Which bones are most likelyto fossilize
– Which bones are most likelyto be left by a predator
– Which bones are most likelyto be washed away by water – How far does pollen travelfrom its source
Reconstructingthe prehistoric environment
– What animals, plants, watersources were present? – What was the temperature?
– Was there a lot ofseasonality?
• Palynology: a tool ofpaleoecology, looks at fossil pollen
– Particular plants typifyparticular environments (e.g., pine trees verses palm trees)
how do weuse shared traits to construct this?
Traits intwo species that have similar structures because they were derived from acommon ancestor. May or may not have similar function.
• Parallelevolution Oftendifficult to distinguish from a homology because this occurs in closely relatedspecies that have recently diverged
• ConvergentEvolution Independent evolution of similaradaptations in rather distinct evolutionary lines
Countsonly shared derived traits, ignores shared primitive traits to form biologicalclassifications.
Focuseson overall physical similarities to group organisms. Counts both primitive andderived traits that are shared, doesn’t distinguish betweenhomologous and convergent/parallel traits
Possess aspinal cord. Also gill slits at some point during development. These traits arewidespread and evolved ~600 million years ago.
Possessbilateral symmetry, and bones covering the spinal cord. Most have similar limbstructure. these traits arose ~520-435 mya
We haveplacentas and give birth to a ‘mature’ fetus. This subclass designation distinguishes us fromProtherians, which are “primitive” mammals:
• monotremeslay eggs (only ones left:
• platypusand two species of spiny anteater).
Wemaintain an internal body temperature. Allows us to live in a wide variety ofenvironments, but is costly.
We havespecialized teeth, which allow us to process a wide variety of foods. But, weonly have two sets.
refers torelatively high amount of parental care (as opposed to r-selected animals likefrogs or fish with little to no parental care). We prefer quality overquantity!
Brains ofall vertebrates have similar structure (hindbrain, midbrain, and forebrain),but differ in size, relative proportions, and functions
:area ofthe forebrain that consists of the outermost layer of brain cells, associatedwith memory, learning and intelligence. Mammals have larger, more convolutedcerebrum, which means more brain cells and more neural connections betweenthem.
Primatesevolved to be arboreal, but several groups later descended from the trees andare adapted to terrestrial life.
overlappingfields of vision (binocular) with both sides of the brain receiving images fromboth eyes (stereoscopic), allowing for detailed depth perception.
Veryuseful for detecting objects in a moderate contrast environment like theforest/jungle, especially in the daytime.
(Alongwith increased reliance on sight is a decreased reliance on smell.)
anexclusive sexual bond for a long period of time. Fathers in monogamous bondsare more likely to show high levels of care.
: asexual bond between an adult male and an adult female in which eitherindividual may have more than one mate at a time.
groupconsists of more than one adult of each sex and the offspring and is the mostcommon non- human primate social group.
Matingtends to be promiscuous. Group composition (number of males, females, children)variable.
22 livingspecies, mostly in Madagascar with some in mainland African and SE Asia
✴ General Characteristics ofprosimians:
✴ rely more on smell thananthropoids.
✴ brains are smaller relativeto body size than anthropoids. ✴ body sizes smaller thananthropoids,
✴ many are nocturnal
✴ many are vertical clingersand leapers.
✴ variable social group size /structure
WHAT ARETHEY CONSIDERED PRIMATES?
Theyshare many derived characteristics with all other primates: ✴ Large brain
✴ Stereoscopic binocular vision
✴ Closed bony ring around eye(but socket not fully enclosed) ✴ Nails (mostly)
✴ Grasping hands
•Found in Asia and MainlandAfrica
•Small, solitary, nocturnal
•Lorises are omnivorous (largemollusks, insects, lizards, birds, small mammals, eggs, gum and fruits)
•Galagos are often gum feeders
•Varied locomotion patternsrelated to stalking prey. Slow vs. Leapers.•And, apparently, they liketo get tickled
Onlyfound in Madagascar. Separated from mainland Africa (and thus Lorises) for 120million years.
•No competition with Anthropoidmonkeys, which do not live in Madagascar.
•Highly variable body sizes,ecological niches, locomotion •Include nocturnal and diurnalspecies
•Nocturnal and solitary
•Convergent with Woodpecker Elongated middle finger usedfor fishing for insects
HigherPrimates” (That’s us) Monkeys(New World & Old World) and hominoids (Humans & Apes).
• Generally larger in overallbody size and relative brain size / complexity thanother primates.
• Rely more on visualabilities.
• Have more complex socialstructures than other primates.
• All except one are diurnal
• Include terrestrial andarboreal species.
• Fullyenclosed eye sockets (unlike Prosimians)
****PLATYRRHINES(NEW WORLD MONKEYS)
Evolved from OWM lineage,diverging 30 million years ago Compared to OWM, NWMs
• have 4 extra premolars
• have prehensile tails (someof them do)
• have flatter noses with side-facingnostrils
• are all arboreal (noterrestrial species)
• NWMs are broadly composed offive families, all grouped under Ceboidea superfamily:• Callitrichidae, Cebidae,Aotidae, Pitheciidae, and Atelidae
Includes5 genera, including spider, howler, woolly, and woolly spider monkeys
•Largest geographic range ofNWM monkeys, extending throughout Central and South America
•Largest body sizes of NWMs •ex: Spider
•Very long arms and tails forbrachiation •ex: Howler...Very folivorous
•Loudest Land mammal. Listen
•Social groups of 6-20individuals. F>M.
CATARRHINES(OLD WORLD MONKEYS)
• Locomotion: All quadrupeds --some arboreal, some terrestrial
• Divided into twosub-families: Cercopithecines and Colobines
• Compared to NWMs, Ole WorldMonkeys:
** arebiochemically and physically more similar to humans (ex: share same dentalformulae 2-1-2-3).
• brain size larger relative tobody size, and more complex.
• Hominoids invest more intheir young (more K- selected)
•***** Lower molar structure isdifferent, with 5 cusps (raised areas on the chewing surface of the tooth)instead of 4 (as monkeys have). Called the Y-5 pattern.
20 - 8mya there were many types of hominoids.Today only a few species survive inthree major categories
Homosapiens: one very dysfunctional species
****Hylobates:4 genera of Gibbons, including 16 species
GreatApes: Pongo (orangutans). Gorilla (gorillas), and Pan (2 “species” of chimpanzees)
used toreinforce bonds and resolve conflict
relaxed matingduring 20 day estrous period
Dominance: Peaceful,Egalitarian societies
Femalesform bonds for mutualsupport and protection Killings almost unheardof
intensemating competition during 10
dayestrous period reproductive tactics of males can
Dominance: Aggressive,Male-dominated societies
Malealliances Inter-group killing
Acheulean Tool Tradition
Technique of flint knapping that requires a prepared surface and precise flaking.
• Changes in anatomy that do not occur at the same rate or the same time.
• This phenomenon is very common in the human fossil record, e.g., the big brain doesn’t evolve until after bipedalism.
Primitive traits: Small brain
Derived traits: Large brow ridges,Flat face, Small teeth
Derived trait: bipedal legs
Primitive trait: long ape-like arms,
Sign up for free and study better.
Get started today!