The document provides information on the geology, plants, and animals of the Lake Tahoe Basin. It describes how the basin was formed over 2 million years ago through geological faulting and volcanism. Glaciers during the Ice Ages helped shape the landscape. The basin contains various rock types including granite, formed from slowly cooled lava. Plants like juniper and animals like the mountain cottontail rabbit and rubber boa snake inhabit the area. Fossil evidence suggests the origins of rabbits date back 55 million years while junipers have existed for 50-72 million years.

1. Evolution of landscapes
and life forms in the
Lake Tahoe Basin
Anna Mason
GEL 103
Summer, 2012

2. Formation of the Lake Tahoe Basin
 The Lake Tahoe Basin was
created over 2 million years
ago by geologic block faulting
and volcanism.
 Modern Lake Tahoe was
shaped and landscaped by
scouring glaciers during the
Ice Ages, which began a Glacier formation and erosion
million or more years ago.

3. Soils of the basin
 As a result of the volcanic
activity and faulting, the basin
contains a combination of
granitic, metamorphic, and
volcanic rocks.
 Some of the valley bottoms
and lower hill slopes are
mantled with glacial
moraines, or glacial outwash
material derived from the Glacial moraine in Angora creek by Meyers.
parent rock.

4. Igneous rocks
 Igneous rocks in the Tahoe
Basin were formed from the
slow cooling of molten lava
that allowed for the crystal
formation of the granitic
rocks.
 The predominant bedrock in
the basin is Cretaceous
granodiorite of the Sierra Sierra Nevada Batholith Granite, Meyers
Nevada batholith.
(Learning, 2010)

5. Granite
 makes up 70–80% of
Earth’s crust,
 makes up most of the
Tahoe Basin’s igneous
rocks,
 large masses of granite
are the ingredients of
mountain ranges,
 it is a plutonic rock, that
forms deep
underground.

6. Granite consists of:
 quartz
 feldspar
 mica
 and dark minerals like
biotite and hornblende.
(Granite, 2003)

7. Basalt
 extrusive igneous rock,
 common type of rock in Earth’s
crust,
 made of many dark colored
minerals such as pyroxene and
olivine,
 also contains light colored minerals
such as feldspar and quartz,
 has very fine grains, individual
minerals cannot be seen without
magnification.

8.  Nodules of basalt from the Watson Creek and
Sawtooth Ridge sources make up a significant
component of the beach gravels along Carnelian Bay.
(Geology)

9. Mountain Cottontail
Sylvilagus nuttallii
Family: Leporidae
Order: Lagomorpha
Class: Mammalia
 The Mountain cottontail is a large Young Mountain Cottontail in our backyard
size rabbit. in Meyers
 The dorsal pelage is brown to gray,
with some black hairs mixed in.
 The belly is white and the tail is
bicolored.

10. Habitat
 The mountain
cottontail is found on
the east slopes of the
Sierra Nevada and the
Cascades.
 Primarily an animal of
rocky, sage-covered hills
and canyons. Range of Mountain Cottontail in
California

11. Diet
 Its diet consist mostly of
grasses and sagebrush, and
will eat juniper berries.
 usually feeds in the shelter
of brush, or in clearings a
few meters from cover.
Adult female Cottontail

12. Reproduction
 Females are nearly five
percent larger than
males.
 The breeding season can
extend from February to
July.
 Four to six young are
born after a gestation
period of 28-30 days.
 Four to five litters can be
produced in a season.
(Streubel, 2000)
Baby Cottontail, from the nest in our
backyard in Meyers.

13. Origins
 In Mongolia, a rabbit-like fossil dated 55
million years back was found.
 The fossil had long hind limbs and was very
close in appearance to modern day rabbits.
 Some differences include a long tail and
squirrel-like teeth.
 This finding suggests that the rabbit family Gomphos elkema,
might have existed for about 65 million years earliest rabbit relative
or more.
(Earliest)

14. Sierra juniper
(Juniperus occidentalis ssp. australis)
 Junipers (Juniperus) belong to the
family Cuppressaceae.
 They have scale-like leaves
arranged in circles of 3, twigs not
forming flat sprays, with berrylike
cones less that ½” in length.
 The wood is fragrant, usually
reddish or reddish-brown, easily
worked, very durable, and rarely
injured by insects. Old juniper in Meyers

15.  Juniperus is primarily dispersed by
birds.The female cone of the Juniper has
been modified to resemble a fruit and
provides significant nutritional value to
birds.
 The foliage and cone-berries of western
juniper are important foods for a number
of mammals. Mule deer, elk, mountain
cottontail, and coyote consume western
juniper cone-berries.
 Decadent trees provide nesting cavities
for mountain chickadees and mountain
bluebirds, and hibernation sites for
several species of bats.
(McRae, 2009)

16. Origins
The serrate-leaf-margin species of North America belong to
Clade II (red) of the 6 major clades of all Juniperus species:
 Fossil and molecular clock data presented by Mao et
al.(2010)indicate that these major clades differentiated
from Cupressus about 50-72 million years ago, during the
Paleocene.
 Disjunctions between Eurasian and North American
species arose at three times:
 30-43 million years ago during the Eocene-Oligocene
transition, when Clade II (red) differentiated;
 5-17 million years ago within Clade III (blue),
 0.3-4.6 million years ago within the Eurasian and North
American varieties of Juniperus communis.
(Mao et al.,2010)

17.  During the past 150 years,
western juniper has
extended its range and now
occupies approximately 42
million acres in the
Intermountain West.
 It grows over
approximately 4 million
acres in the Pacific
Northwest.
Native range of western juniper

18.  Many native people have
used the aromatic foliage and
resins for medicinal or
spiritual purposes.
 An essential oil is obtained
by distillation from wood and
leaves and used for
perfumery, or medicine for
its powerful diuretic
properties.
(Adams)

19. Rubber boa
(Charina bottae)
Phylum Class Order Family
Kingdom
ANIMALIA CHORDATA REPTILIA SQUAMATA BOIDAE
 non-venomous, small to medium sized snake
that may reach about 80 cm.
 they vary in color: from olive green, pink,
orange, cream or yellow to dark brown,
usually with a yellow belly.
 rubber boas live in many habitats in
California, including moist forest, dry pine
forest, and shrubby habitats.
 it is hard to spot them during the day because
unlike most snakes, rubber boas seem to
prefer cool temperatures, and are often active
throughout the middle of the night. I found this young rubber boa
crossing Sawmill Road one late
afternoon.

20.  this small constrictor snake has a stout body
and smooth shiny small-scaled loose and
wrinkled skin which gives the snake a rubbery
look and feel. I thought that it was a plastic
toy snake on the road when I found it.
 the bones of the tail are fused into a solid
block that is very strong.
 they never bite, but instead curl up into a ball
when disturbed; they often hold their blunt
tail up, and even make fake "strikes" with it.
 rubber boas often eat young rodents, and
they probably use the blunt tail to defend
ward off the adult rodents. Many snakes have
scars on the tail from rodent bites.

21.  a good burrower, climber and
swimmer.
 often found under logs, boards and
other debris, sometimes on roads at
dusk.
 known to live as long as 40 - 50 years
in the wild.
 bears 1 - 9 live young from August to
November.
(Charina)
Range of the Rubber Boa in California in red

22. Origins
 Aniliids, morphologically primitive
among living snakes, feed on relatively
heavy, elongate vertebrates. Large
aniliids eat larger prey than do small
individuals but, as in advanced snakes,
they also take small items.
 very early snakes used constriction and
powerful jaws to feed on elongate,
heavy prey. This would have permitted
a shift from feeding often on small
items to feeding rarely on heavy items,
without initially requiring major
changes in jaw structure relative to a
lizard-like ancestor.
(Greene,1983)

23. Works cited
 Adams, R.P. (2010) Juniperus (juniper) Description. N.p. Retrieved from
<http://www.conifers.org/cu/Juniperus.php>.
 Charina Bottae (n.d.) Northern Rubber Boa." Charina Bottae. Retrieved from
<http://www.californiaherps.com/snakes/pages/c.bottae.html>.
 Earliest Rabbit Fossils Found (n.d.) American Museum of Natural History. N.p. Retrieved from
<http://www.amnh.org/science/papers/rabbit.php>.
 Geology and Soils of the Lake Tahoe Basin. (n.d.) Rep. N.p.: EDAW, n.d. Print. Retrieved from
<http://www.placer.ca.gov/Departments/CommunityDevelopment/EnvCoordSvcs/EIR/TVD
evProject/~/media/cdr/ECS/EIR/TahoeVista/Ch9GeologySoils.ashx
 Granite (2003) World of Earth Science.Encyclopedia.com. Retrieved from http://www.encyclopedia.com/doc/1G2-
3437800262.html
 Greene, Harry W.(1983). Integrative and Comparative Biology. Dietary Correlates of the Origin and Radiation of Snakes.
N.p. retrieved from <http://icb.oxfordjournals.org/content/23/2/431.short>.
 Learning Center (n.d.) Lake Tahoe Basin Mgt Unit -. N.p. retrieved from
<http://www.fs.usda.gov/detail/ltbmu/learning/?cid=stelprdb5109570>.
 Macrae, Ted C. (2009, April 4.)Trees of Lake Tahoe , The Other Conifers. Beetles In The Bush. WordPress. Retrieved
from <http://beetlesinthebush.wordpress.com/2009/04/04/trees-of-lake-tahoe-the-other-conifers/>.
 Mao Kangshan, Hao Gang, Liu Jianquan, R. P. Adams and R. I. Milne. (2010). Diversification and
biogeography of Juniperus (Cupressaceae): variable diversification rates and multiple
intercontinental dispersals. New Phytologist 188(1): 254-272.
 Streubel, Donald. (2000) Mountain Cottontail. N.p. Retrieved from
<http://imnh.isu.edu/digitalatlas/bio/mammal/Lagom/moco/moco.htm>.