Final Flashcards
Get an A
8 or 7 mya-
common ancestor between chimps, gorillas, and hominins
2.5/2.4 mya-
earliest stone tools to butchery. Meat higher incorporated into diet
1.8-1.5 mya-
many hominin species in Africa w/ different adaptations. Possibly fire
800 kya-
or possibly fire here. Greater volatility in climate. Faunal turnover. Divergence between MH and N/D
200 kya-
morphologically Neanderthals in Europe
100-50 kya-
MH migrate out of Africa and mates with N. MH go to Australia
40 or 39 kya-
N disappear
23-12 kya-
immigration of homo sapiens into Americas
Sixth Mass Extinction
Holocene - present
1.3% of mammal species extinct
At least 20% in half of mammalian orders
Glacial-Interglacial Cycles
Large continental ice sheets in the Northern Hemisphere have grown and retreated many times in the past. We call times with large ice sheets “glacial periods” (or ice ages) and times without large ice sheets “interglacial periods”. The most recent glacial period was about 120,000 and 11,500 years ago. Since then, Earth has been in an interglacial period called the Holocene.
Glacial periods are _______, ______, and generally _____ than interglacial periods
colder, dustier, and generally drier
What causes glacial-interglacial cycles?
Variations in Earth’s orbit have changed the amount of solar radiation in the Northern Hemisphere. These glacial-interglacial cycles have waxed and waned throughout the Quaternary Period (the last 2.6 million years.) Since the middle Quaternary, glacial-interglacial cycles have had a frequency of about 100,000 years.
In the solar radiation time series, cycles of this length (known as “eccentricity”) are present but are weaker than cycles lasting about 23,000 years (which are called the “precession of the equinoxes”).
Solar radiation varies smoothly through time with a strong cyclicity of ~23,000 years.
Interglacial periods tend to occur during periods of peak solar radiation in the _________ ___________ summer. However, full interglacials occur only about every _____ peak in the precession cycle.
Northern Hemisphere, fifth
Heinrich and Dansgaard-Oeschger Events
(D-O)Rapid climate fluctuations that occurred 25 times during the last glacial period.
(Heinrich) a natural phenomenon in which large armadas of icebergs break off from glaciers and traverse the North Atlantic.
The Younger Dryas
One of the most well-known examples of abrupt change
About 14,500 years ago, Earth’s climate began to shift from a cold, glacial world to a warmer, interglacial state
Partway through this transition, temperatures in the Northern Hemisphere suddenly returned to near-glacial conditions. This near-glacial period is called the Younger Dryas, named after a flower that grows in cold conditions and became common in Europe at this time
The end of the Younger Dryas, about 11,500 ya was particularly abrupt. In Greenland, temperatures rose 10 C (18 F) in a decade
Clovis Points
~12,800 to 13,100 BP
Buttermilk Creek Complex:
15,500 BP
North American Extinction When?
10000 and 12000 years.
Butchered mammoth bones excavated in southeastern Wisconsin date regional human presence to between ___ and ____ ka
14.8 and 14.1
Current Risks
Extreme Climate Change Nuclear War Global Pandemic Ecological Collapse Global System Collapse
Exogenic Risk
Major Asteroid IMpact
Super-Volcano
Emerging Risk
Synthetic Biology Nanotechnology Artificial Intelligence Unknown Consequences Future Bad Global Governance
Madagascar: Geographic and Geological History
World’s 4th largest island
About the size of California
Located 400 km east of Africa in Indian Ocean
Originally part of Pangaea, later Gondwanaland
Broke off and reached current position relative to Africa 130my
India broke off 88 my, Australia and Antarctica probably earlier
Madagascar: Climate and Environments
Mostly tropical, incredibly varied North and West: Dry forests East and Sambirano: humid forests South: Spiny forest Central plateau: cool, mix of grassland and woodland Long history of climate instability
Madagascar: A naturalist’s paradise
Varied environments help maintain high levels of biodiversity Long isolation has led to high levels of unique biodiversity (endemism) 52% of bird species 80% of flowering plants 95% of reptiles 99% of amphibians 100% of primate species are endemic >100 extant species, 5 families
So lemurs are extremely diverse in
Total number of species
Phylogenetic distinctiveness
Number of species unique to their environment
Lemur Origins
Lemurs are related to other strepsirhines from Africa, Asia (galagos, pottos, lorises)
Strepsirhine traits:
Large eyes, tapetum lucidum
Moist noses (rhinarium), reliance on scent marking
Dental comb
Grooming claw (2nd digit of foot)
Lemurs split from African common ancestor ca. __-__mya
57-75 mya
Began to diversify from single common ancestor in Madagascar ca.
50-60 mya
How did lemurs get to Madagascar?
Rafted from Africa
“Sweepstakes dispersal”
Evidence from genetics, fossil record, palaeogeography (including ancient currents)
Except… (evidence for lemur relation)
Propotto: 16-23 mya, Kenya
Plesiopithecus: 34 mya, Egypt
Teeth are similar/evolved like Madagascar lemurs
Could move lemur to Madagascar date to 20-40 mya
With less competition, lemurs underwent
adaptive radiation
Lemur variety in activity
diurnal (day), nocturnal (night), cathemeral (both, activities occur during day and night, and some shift from mostly daytime to mostly night over a yearly cycle)
Lemur variety in diet
frugivory (fruit), folivory (leaves), insectivory, omnivory, gumnivory, granivory
Lemur variety in vertical space
arboreal, terrestrial
What are ecosystem services?
Ecosystem services are the many and varied benefits that humans freely gain from the natural environment and from properly-functioning ecosystems
Four categories of ecosystem services
Supporting
Nutrient recycling, primary production and soil formation
Provisioning
Food, raw materials, genetic resources, water, energy
Regulating
Pollination, carbon sequestration, waste decomposition, purification of water and ai, pest control
Cultural services
Use of nature as motif in books, film, spiritual and historical, recreation, science and education
Lemur families
Lemuridae: diverse, medium size
Lemur catta
Prolemur simus
Indriidae: Largest body size
Propithecus verreauxi
Indri indri
Lepilemuridae: Single living genus; 19 species (up from 8 in 2006)
Lepilemur edwardsi
Cheirogaleidae: Smallest body size; torpor
Microcebus rufus
Mirza zaza
Daubentoniidae: Monotypic genus, highly specialized extractive forager
Daubentonia madagascarensis
Lemur Traits
Small group sizes Many pair-bonded species Low basal metabolic rates (BMR) Highly seasonal breeders: 1-2 weeks/year Female dominance Sexually monomorphic Priority of access to food Lead group movements Small body size Adaptations to unpredictable climate Energy conservation
Lemur body size distribution
Strepsirhines from <0.5 to 4-5
Old World Monkeys and Apes from 4-5 to 100+ (going down sharply from 5-8)
Extinct Lemurs
In the last 1000 years, 8 genera and > 17 species disappeared
No lemur fossil record older than 20 ky
Subfossils, mostly found in caves
Extinct Lemurs (types)
Lemuridae Pachylemur 10kg Arboreal frugivore Related to Varecia Archaeolemuridae
Archaeolemur, Hadropithecus
“Monkey lemurs”
15-25 kg
Terrestrial, diverse diets
Paleopropithecidae Paleopropithecus, archaeoindris, babakotia, mesopropithecus “Sloth lemurs” 10-200 kg Mostly arboreal, suspensory
Megaladapidae Megaladapis “Koala lemurs” 20-80 kg Slow climbers
Extinctions were non-random
All extinct genera were diurnal
All extinct species were larger
Largest living lemur: Indri (6-7 kg)
Largest extinct lemur: Archaeoindris ≤ 200 kg
Humans arrived Madagascar ca.
2000ky
Earliest settlers likely from Borneo
Among most distant colonization events in human history (on outrigger canoes)
Successive migrations from East Africa
Economies based on agriculture (slash-and-burn rice cultivation) and herding (cattle imported from Africa and Asia)
Early evidence of hunting of wildlife
Habitat loss
Slash-and-burn agriculture led to clearing of forests
Large areas burned for cattle pasture (“green bite”)
Large body size = large range requirements
Cattle and other domesticates competed with native fauna
Slowest and largest species may have been preferred prey
How are surviving species different?
Reduction in body size
Smaller geographic distribution
Nearly absent from central high plateau
Greatly reduced in all other regions
