Bio 117 Lecture 14

Front 1

Community

Back 1

consists of living, interacting organisms in a given location.

It had an ecological separateness to it (e.g., parasite and its host, predator-prey interactions, mutualisms).

Front 2

Community Scale

Back 2

Can be very small (a vernal pool) or large (great lake).

This can be the same for ecosystems.

Community scale focuses on just the organisms and their interactions.

Front 3

Emergent properties of communities

Back 3

e.g. succession

the sequence of recovery of species following species removal as result of a disturbance (e.g., volcanic eruption, land clearing).

Front 4

Ecosystem

Back 4

A community + abiotic environment (e.g., solar radiation, temp, minerals, water, etc)

Front 5

Ecosystem Scale:

Ecosystems can exist at many different scales e.g: ?

Back 5

1. Decaying leaf ecosystem in a vernal pool (a tiny water basin created by snow melt and precipitation, but drying up later- this is in BU nature preserve)

2. BU nature preserve: the multiple beaver ponds and adjacent habitat

3. Watershed: area of landscape that drains into a particular river/stream

4. Temperate forest

Front 6

Emergent properties of ecosystems

Back 6

1. Productivity/Energy Flow

2. Hydrological Cycling

3. Nutrient Cycling

Front 7

Biome

Back 7

Major terrestrial ecosystem defined by global climate patterns and characterized by distinct assemblages of animals, plants, and regional abiotic variables.

Front 8

Determinants of Global Climate Pattern

(4)

Back 8

1. Solar Radiation

2. Earth's Rotation

3. Seasons

4. Mountains

Front 9

Solar Radiation causes:

(2)

Back 9

1. Vertical air mass circulations

2. Vertical water mass circulation

LOOK UP IN NOTES (many things about this stuff!)

Front 10

Vertical Air mass circulations

Back 10

hot air picks up moisture from ground and sea

heated air expands, becomes less dense, rises, and becomes cooled

this lowers moisture carrying capacity of air and causes excess water vapor to condense in form of precipitation near the equator

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Front 11

Deserts: very dry, arid conditions around 30 degrees latitude

Due to:

Back 11

Expanding air high in the atmosphere moves pole ward (away from the region of expansion) and as it cools and becomes more dense, descends at 30 degrees N and S latitude. HENCE deserts

Front 12

Hadley Cell

Ferrell Cell

Polar Cell

Back 12

Some of the air at 30degrees is drawn back toward the equator to replace the air that ascended when heated, creating a cyclic circulation of air parallel to the earths surface between 0 and 30 degrees- (HADLEY CELL)

This downward flow at 30 degrees causes secondary and tertiary cells poleward: between 30 and 60 degrees (FERRELL CELL)

and between 60 and 90 degrees (POLAR CELL).

Front 13

Hadley Cell

Ferrell Cell

Polar Cell

Where do they occur

Back 13

They occur Both N and S of the equator, 6 total in all, with the circulation between 30 and 60 degrees being opposite to the others.

Front 14

Vertical water mass circulation

Back 14

LOOK UP IN NOTES

Front 15

Vertical water mass circulation

Back 15

Warm water on top and cold water 100m down in the ocean.

The chilling of polar water and the increased salinity resulting from surface evaporation during chilling increase the density of polar seas and cause the sinking of sea water and its deep flow away from the poled toward the equator.

The warm surface water from the "near the equator seas" are drawn poleward to replace the sinking polar sea water.

this combination of events is the "engine" that drives the N/S component of the ocean conveyor (global pattern of ocean surface/ deep water currents).

Front 16

Earths Rotation

1. Horizontal air mass response to rotation

2. Horizontal oceanic current components resulting from the earth's rotation

Back 16

LOOK UP IN NOTES

Front 17

horizontal air mass response to rotation

Back 17

Air rises as it is heated and moves poleward (paths of less resistance to flow), slowing at about the same rate as the earth's surface. After it descends at 30N/S some of it is drawn back along the earths surface to the equator. The earth moves towards the equator slower than the earth's rotation and is perceivd by people in the subtropics as prevailing easterly winds (from the east).

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Front 18

Horizontal Oceanic current components resulting from the earth's rotation

Back 18

Gyres

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Front 19

Seasons

Back 19

The rotation of the earth around the sun and the tilt in the earth's axis relative to the sun's position.

Extremely low temperatures and low solar radiation during the winter near poles limit biodiversity

The band of wet equatorial weather near 0N/S and arid conditions near 30N/S moves seasonally with the seasonal tilt in the rotational axis, creating wet and dry seasons.

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Front 20

Mountains

Back 20

LOOK UP IN NOTES

EASY

Front 21

Major Terrestrial Ecosystems

Back 21

BIOME

Front 22

Tundra

Back 22

mostly treeless, except for mini trees few feet high.

not enough sunlight/nutrients for production of woody tissue, which do not photosynthesize food, and is a for drain on resources for reproduction

Front 23

High elevation tundra

Back 23

alpine tundra

southern most alpine tundra- Arizona

Front 24

Alpine Tundrs

Back 24

Moist cold

pika: stores grass at nest for insulation and food

Marmot(high elevation ground hog)- reduces reproductive rate and becomes more social as a means of conserving energy. Maturation takes 3xs longer in high elevation species due to shorter season for growth and reproduction

Front 25

Alpine tundra (high elevation)

how much?

Back 25

Approx 600 feet elevation is equiv to 1 degree latitude

Alpine tundra begins at 12,000 feet in colorado (40 degrees N) but at sea level 60N latitude

Front 26

High latitude tundra

Back 26

Arctic Tundra

Generally above 60 degrees north latitude (mostly above the Artic Circle at 66N)

Front 27

Conditions of Arctic Tundra

Back 27

1. cold and damp, low evap rates and low precip rates

2. not much vegetation

3. Ptarmigan, Golden Plover: ground nester with cryptic coloration; small food supply many mammals flee into the hills during spring to avoid black flies and mosquitoes in warmer valleys

4. snowy owls and arctic fox feed on lemmings

5. low biodiversity; high carbon stores in permafrost without decomposition

Front 28

Conifer Forests

AKA northern boreal forests

Back 28

almost entirely coniferous, except for larch; low diversity of trees, needle retention lowers nutrient needs for maintenance; allows earlier photosynthesis in the the spring

Front 29

Characteristics of Conifer Forests AKA northern boreal forests

Back 29

1. Catastrophe prone forests- shallow root growth ( easy wind throw damage), insect devastation

2. browsing animals keep many areas in early succession

3. red woods (tallest tree in the world)

4. giant sequoia (most massive)

5. Bristle cone pine (oldest)

6. spire-shaped trees, with needles close to ground- reduces wind/snow damage

7. Lynx is typical carnivore, snowshoe hare- mammalian prey

8. Brown Bears

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Front 30

Grasslands

Back 30

Prairie, Pampas (SA), Veldt, Steppes)

Front 31

Characteristics of Grasslands

Back 31

1. converted to agriculture because of rich soils

2. warm and dry

3. broadly similar to arctic tundra; low vegetation

4. wind pollination works here (unlike trop rain forest)

5. fire important for prairie maintenance and nutrient re-cycling

6. ants- IMPORTANT prairie soil conditioning

Front 32

Savannah grassland

Type of grassland


Characteristics?

Back 32

1. mostly dry and warm but highly seasonal rains; some acacia trees

2. important in human evolution- primates came out onto the savanna- upright walk to look over grass

3. termite mounds, wildebeest

Front 33

Temperate deciduous forests

(mainly between 30 and 45 degrees north)

Back 33

1. most energy is processed with release of CO2 after leaves die and fall (energy is stored in summer and spring in leaves)

2. many detritivores, fungi, millipedes

3. rich soils and thick hummus because of moisture and rich community of decomposers

4. skunk, raccoon, red fox, white-tailed deer, black bear, deer mouse

Front 34

Deserrt

Back 34

mostly around 30 degrees north and south latitude

Front 35

Characteristics of Desert

Back 35

1. Dry and hot

2.some plants and animals with water conserving structure (e.g., leaves reduced to thorns.

3. horned lizard, diamond back rattlesnake and kangaroo rat all adapted for living in xeric (very dry) conditions- thermoregulatory animal behavior (avoid mid-day activity)

4. kangaroo rat doesnt drink water; water comes from his food

Front 36

Tropical Rain forests

Back 36

within 20 degrees of equator

most biodiverse 2/3 of all known living organisms live here

Front 37

Tropical rain forests have Complex structure of vegetation

Back 37

1. Buttress roots- compensate for thin soils resulting from rapid decomposition

2. big leaves (gather reduced light lower in canopy)

3. Epiphytes (plants living on plants; orchids and bromeliads)

Front 38

Other characteristics of Tropical rain forests

Back 38

1. complex vegetation

2. several layers of trees with very tall ones

3. lots of vines using trees as support (strangler fig)

4. consumers are mostly arboreal (live in trees), even the ants, termites, herps (amphibians/reptiles)

5. warm and moist year round- great for fungi- leaves decay quickly

6. tremendous selection pressure- predation and competition

Examples- Katydid crypsis of dead leaf shows predation to be a strong selective agent AND plant chemical defenses are common

7. sloth, bats, macaw, parrots, cats (margay), tree iguanas, ants, termites

Front 39

Aquatic ecosystems

Back 39

aquatic biodiversity varies considerably with both global and local factors.

Sunlight penetration, temp, O2 availability and nutrient availability are major abiotic determinants of biodiversity

Front 40

Fresh water habitats

Back 40

1. vernal pools

2. ponds

3. streams

5. wetlands

6. Swamps

6. Lakes

7. Rivers

Front 41

Characteristics of Habitats

Back 41

LOOK UP IN NOTES

Vernal pools- spotted salamanders and wood frogs (pools important-reduce flood potential)

ponds- year round water basins with cattails and amphibians, lots of water plants and insects; duckweed, red-winged blackbirds

streams (sculpins, minnows)

wetlands (tannic acid build up from decaying organic vegetation and sphagnum moss), low pH

swamps (cypress)

Lakes NOTES

Rivers- (support many fishes, algal films, macrophytes in shallows)

Front 42

Brackish water systems (Bays)

Back 42

mixes salt.fresh water, euryhaline fishes; oysters, crabs

1. salt marshes (somewhat isolated, very high salt conditions; salt-tolerant plants and animals)

2. Bays, estuaries (waterfowl sancturaries); stratification of freshwater over saltwater

Front 43

Marine Ecosystems: has two major zones

Back 43

Intertidal (highest nutrient content, but harshest living conditions: periodic exposure to dehydration, UV radiation and wave action)

Neritic Zones (shore out to continental shelf edge) most accomodating due to more gentle water than intertidal, sunlight for photosynthesis, nutrient recycling from bottom; many organisms have phytoplankton symbionts (flatworms, mollusks, jellyfish, corals)

Front 44

Intertidal

Back 44

(highest nutrient content, but harshest living conditions: periodic exposure to dehydration, UV radiation and wave action)

Front 45

Neritic Zones

Back 45

(shore out to continental shelf edge) most accomodating due to more gentle water than intertidal, sunlight for photosynthesis, nutrient recycling from bottom; many organisms have phytoplankton symbionts (flatworms, mollusks, jellyfish, corals)

Front 46

Neritic Zones

Back 46

1. Kelp Forests

2. Coral Reefs CaCO3 skeletons (reefs)

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Front 47

Another Marine Ecosystem:

Oceanic

Back 47

1. Mostly nutrient-poor because dead organisms float down below the thermocline to the ocean floor (Fe is particularly limiting)

2. No attached plants/algae; floating alga Sargassum support mini oases of life

3. Daily burst of phytoplankton growth with vertical migration of zooplankton coming to the surface at night to safely feed on the phytoplankton, returning to the depths at dawn