Week 1 lecture notes
Pre-quiz given, counts as extra credit.
Intro to tropical ecology
Many tropical ecosystems – tropical forests occupy 7% of earth’s
surface, but include 50% of the world’s biodiversity!
Biodiversity
= Biological richness of an area, usually defined as the number of
species. Example: 3 doves, 5 parrots, 2
woodpeckers = diversity of 3.
Tropical rainforests – 57% are located in the Neotropics (Western Hemisphere).
(30% rainforests are in Brazil) – See Figure 52.5.
At the
current deforestation rate, in 177 years all tropical rainforests will be gone. We will find out what that means for the rest
of the earth as we learn about the functions of rainforests and other tropical
biomes.
Before we continue, let’s talk about what ecology is. Who can give some definitations?
Ecology = The scientific study of the interactions among
organisms and between organisms and their environment.
Living organisms can be grouped together into communities – all the organisms
in an area.
Example - Aquatic
community = frogs, egret, fish, dragonflies, turtles, aquatics plants such as
cattails, reeds,. What separates this
from other communities? The
ecosystem. A Forest community is
different = woodpeckers, tako (cuckoos), beetles, tree snakes, tarantulas, palm
trees, ferns, etc.
Ecosystem = the system embracing
the organisms plus their physical
environment.
Environment
is composed of both biotic –
living, biological things & abiotic
factors. – chemical and physical examples = water quality, temp etc.
Why should we care about all this? Ecosystems provide goods and services people
need. List some examples: Clean air & water, timber, food,
fertile soil, etc.
Geography – where are the tropics?
Know these terms - Latitude and longitude, Eastern and
Western, Northern and Southern hemispheres, Equator is at 0 degrees latitude. Prime meridian is at 0 degrees longitude (runs through
England)
Tropic of Cancer = 23˚
27’N and the Tropic of Capricorn = 23˚
27’S.
·
Read as 23 degrees, 27 minutes north or south.
·
Here the sun is overhead all year.
Earth is tilted at 23˚ 27’! Therefore in North sun is overhead in June 21
– Sep. 21,
and in South sun is overhead Dec 21 – Mar 21.
·
Sun’s radiation falls most directly & most
constantly upon the equator.
o
Area between 23 27’ N & S = TROPICS!
o
Equal time of sun at equator = 12 hr
o
Relatively consistent temperature all year.
·
In either hemisphere rays are more oblique,
o
Day length differs throughout the year.
o
Temperature differs throughout the year (therefore
seasons).
Biomes are
terrestrial environments defined by the growth forms of its plants.
They are influenced by geography
& climate, & determined by plants!
Influenced
by annual precipitation & temperature which vary throughout the year. See Fig 52.5 (from Life 8th ed., and click for the web tutorial)
1. Tundra
a.
arctic & high elevations of mountains.
b.
soil frozen, low growing plants with growth a
few months a year, animals migrate or hibernate
c.
temperature -25C to 5C (-13F to 41F)
d.
23 cm precipitation = 2 inches
2. Temperate Deciduous Forest
a.
Eastern US
b.
Wide flux in temperature winter to summer -5C to 30C (23F to 86F)
c.
81 cm precip
snow and rain
d.
Trees loose leaves in winter
3.
Temperate Grassland
a.
Central US
b.
Wide flux in temperature winter to summer -5C to 35C
(23F to 95F)
c.
31 cm precip snow and rain
d.
Grasses and forbs (herbaceous plants), few trees
= AGRICULTURE
4.
Desert – Cold
a.
Southwest US
b.
Wide flux in temperature winter to summer 0C to 25C (32F to 77F)
c.
38 cm rain
d.
shrubs
5.
Desert – hot
a.
Mexico
b.
Narrow range of temperature 25C to 35 C (77F to
95F)
c.
15 cm rain!
d.
Succulent plants – cactus
6. Thorn Forest and Tropical Savannah
a.
Edge of hot desserts, on the tropical side
b.
Narrow range of temperature 25C to 35 C (77F to
95F)
c.
A lot of rain
74 cm
d.
Spiny shrubs, small trees loose leave during dry
winter. Where it is grazed by large
animals we have savanna – grasses with scattered trees. – AFRICA with giraffes, antelope, etc.
7. Tropical Deciduous
a.
Move towards equator and replace above biome with
this biome
b.
Narrower range temp 22C to 27 C
c.
Even more rain 163 cm
d.
Most trees loose leaves during dry season
e.
Rich soils, thus have been cleared for agriculture
8.
Tropical
Evergreen – Haiti
a.
Move towards equator and replace above biome with
this biome
b.
Even narrower range temp
c.
Even more rain >250cm
d.
Highest in biodiversity, and more epiphytes
(plants that derive moisture and nutrients from air and water rather than soil)
e.
Poor soils since most nutrients are tied up in
the vegetation
LAB – Parts of a Journal Article - Article 1 about Macaya birds
Homework for next week: Read Article 1 and write a one page paper
answering:
1.
Purpose of the study (why)
2.
When and where the study took place
3.
How the researchers captured the birds
4.
List 2 results of the study
5.
List the conservation recommendations
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