Bio Exam 4- Intro to Ecology

Ecology is the study of how organisms interact with______________

→their biotic environment (other organisms)

→their abiotic (physical) environment

Organismal Ecology

examines the morphological, physiological, and behavioral adaptations that allow organisms to live where they do

Population Ecology

examines group level biology in one species

Population

a group of individuals of single species living in close proximity and capable of interbreeding

Community Ecology

examines interacts among different species

Community

a set of interacting species that live within a defined area

Ecosystem Ecology

how do all the components of the biotic and abiotic environment inter-relate

Global Ecology

how is the biosphere affected by global changes in nutrient cycling and climate

Biogeography

the geographic distribution of an organism in its range

Niche

a species’ range depends on biotic and abiotic conditions

→the range of biotic and abiotic characteristics that a species can tolerate is its niche

Abiotic Factors

light, oxygen, nutrients, temperature, rainfall

Biotic Factors

competitors, prey distributions/food supplies, predators, pathogens/hosts, pollinators

Climate

The prevailing, long term weather conditons

Weather

specific, short term atmospheric conditions of temperature, precipitation

Why are the tropics warmer than the poles

At increased latitudes, the sun strikes the surface of the earth at increased angles

→avg temp decreases with increasing latitude

What causes seasonality

annual variability in temp is due to Earth’s axial angle in orbit

→surface angles to sun changes over seasons

Why are tropics wet

Rainfall tends to be:

→high at the equator

→low at 30 degrees N and S latitude

→high at 60 degrees N and S latitude

→low at poles

Hadley Cell (Global Rainfall Patterns)

global air circulation cell at the equator

Additional Cells (Global Rainfall Patterns)

Similar cells occur at mid-latitude and at the poles

→air doesn’t move straight north or south due to the spinning of the Earth on its axis

Coriolis Effect (Global Wind Patterns)

spinning of the Earth means that air (and water) tends to be deflected

→ to the right (clockwise) in the northern hemisphere

← to the left (counterclockwise) in the southern hemisphere

Rain shadow effect leads to__________

wet and dry sides of range

Oceans tend to _______

moderate heat

Water has a high ______

specific heat

Absorbs heat in the summer →

staying cooler than air temps

Releases heat in winter →

stays warmer than air temps

Biomes

a region characterized by a distinctive set of abiotic conditions

Net primary productivity

total amount of biomass generated through carbon fixation minus the amount oxidized during respiration

NPP

determines the organic material that is available to consumers

Biomass

the total mass of organisms

Tundra

-found at high latitudes or elevations

-precipitation very low

-low temp

-extreme variation in daylength

-low productivity

-low species diversity

-vegetation:grass, sedges, mosses, lichens

-permafrost*

Boreal Forest (Taiga)

-Precipitation low (higher than tundra)

-low temp

-variation in daylength

-soils acidic, nutrient poor → unsuitable for agriculture

-low productivity

-high above ground biomass

-low species diversity

-vegetation: coniferous trees, spruce, fir, pine

Temperate Deciduous Forest

-Precipitation moderate

-Temp moderate

-seasonality, particularly temp

-moderate productivity

-moderate species diversity

-Vegetation: deciduous trees dominant

Grassland (Prairie)

-Precipitation low-moderate

-Temperature moderate

-Seasonality: both temp and rainfall

-Moderate productivity (lower than in forests)

-Fertile soils

-Vegetation: grasses dominate

-Lack of trees

Subtropical Desert

-Precipitation extremely low

-Extreme temperatures (high in subtropics)

-Extremely low productivity

-Vegetation: xerophytes like cacti

Tropical Wet Forest (Rainforest)

-Precipitation high, with seasonality

-constant temps (moderate to high)

-high productivity

-high species diversity

-high aboveground biomass

-Infertile soils

-Vegetation: broadleaf trees dominate

Aquatic Biomes

water depth affects sunlight availability

-distribution of wavelengths changes with depth'

-strong effects on capacity for photosynthesis

Intertidal zone (Ocean Zones)

along the coastline-exposed to air at low tide

Neritic zone (Ocean Zones)

above the continental shelf- up to 200m deep

Oceanic Zone (Ocean Zones)

open ocean

Photic zone (Ocean Zones)

sunlit zone

Aphotic zone (Ocean Zones)

areas that do not receive sunlight

Benthic Zone (Ocean Zones)

bottom of the ocean

Littoral Zone (Lake Zones)

water along the shore where plants can take root

Limnetic Zone (Lake Zones)

water offshore that is too deep for plants

Coastal Runoff

as rivers move toward the ocean, they pick up debri and nutrients from the land

→rivers tend to widen near the ocean, waters slow, nutrients are deposited on bottom

Estuaries

are shallow and nutrient rich (one of the most productive biomes)

Lake Turnover

In winter surface has more oxygen

→diffusion

→water is densest at 4 degrees celsius

In spring, surface temp rises to 4 degrees celsius

→water is now heavier at surface and sinks

→displaces lower water, which rises

In summer, new thermocline forms

In fall, the surface water cools to 4 degrees celsius and sinks

→mixing nutrients and oxygen