Ecology Fall 2025

Ecology

The study of relationships between organisms and their environment

Evolution

A process by which populations change over time

Individual

An organism

Population

multiples of a single species

Interactions

influences between species or their environment

Community

Many different species within a particular area

Ecosystem

Many species interacting with their environment in a particular area

Biomes

Areas defined by dominant vegetation and climate

Region

A large area including multiple ecosystems and possibly multiple biomes

Biosphere

The portions of earth that support life including land, water and atmosphere

Explain what Robertson MacArthur realized

Separate species of warblers with similar niches could coexist by inhabiting different parts of trees

Stable isotope analysis

Isotopes of carbon have different masses (due to different neutrons) and these isotopes have different abundances in different organisms

Nutrients

The raw material that an organism must acquire from the environment to live

Epiphytes

Non-parasitic plants that grow on the branches and trunks of other plants

what did Margaret Davis find out about lake sediments

They contained pollen from thousands of year ago, the stratification of these layers showed changes in vegetation over time

What was Daniel Janzens goal

To restore tropical dry forests to Guanacaste National Park

What is so significant about Guanacaste trees? What are current techniques to increase their populations?

They have seed pods that were meant to be digested and spread by ancient herbivores, modern techniques use horses to eat and spread the seeds

What causes seasons

Uneven heating from the sun, along with earths tilted axis

what is an atmospheric circulation cell

Where warm air rises and moves north/south, then runs into cooler air and sinks, warm air can be moist or dry

What’s the coriolis effect

Winds from the very south deflect left and winds from the very north deflect right

What is a soil profile

The distinguishably stratified layers of soil (thicknesses vary)

O horizon

The first layer of a soil profile, the freshly fallen organic material

A horizon

The second layer of a soil profile. Contains minerals like sand, clay and silt. As well as organic matter from O horizon

B horizon

The third layer of a soil profile. Contains clays, humus, and water transported materials. Also contains roots

C horizon

The fourth and deepest layer of a soil profile. Contains smaller weathered material from other layers, worked down by the actions of frost. Rock fragments and bedrock is also found.

What is a tropical rainforest

A forest within 30 degrees lat, warm and wet year round, receiving more rainfall than plants require for growth, more rainfall than evaporation

Why are tropical rainforests within 30 degrees of the equator?

Heat from the sun evaporates ocean water and creates heavy rains over the equator

Why are deserts located around 30 degrees Lat

the warm air that rained on tropical rainforests now moves north or south as dry hot air

what are climate diagrams?

A tool designed by Heinrich Walter to explore the relationship between the distribution of terrestrial vegetation and climate.

Tropical dry forests

Warm and wet forests that experience dry and intense wet seasons

Tropical savanna

A warm grass land that receives wet and intense dry seasons

Deserts

Warm dry environments where annual evaporation exceeds rainfall

Mediterranean woodland

above 30 degrees lat, shrub lands with intense wet and dry seasons

Temperate grassland

temperate lands with fire resistant grasses and low tree density due to natural wildfires

Temperate forest

Temperate areas with high deciduous and medium conifer density and moderate rainfall exceeding evaporation

Boreal forest/taiga

Cold areas with moderate rainfall, permafrost, and dense conifer forests, high temp variation

Tundra

Cold, dry areas with solidly ruin that move the permafrost through temperature shifts. 24hrs daylight/night time

Mountains

Created by geological activity, mountains can exhibit many biomes in a small area because increase in altitude simulated increase in latitude

The hydrologic cycle

How water moves among different reservoirs (atmos, ocean, lakes, rivers, ground water)

Ocean currents

Pushed by wind and deflect from continents. Carry nutrients, temperature changes, and salinity levels

Littoral or intertidal zone

Shallow shoreline under influence of the tides

Neritic zone

Extends from the coast to the continental shelf

Oceanic zone

The ocean beyond the continental shelf

Epipelagic zone

The 200m deep surface of the ocean

Mesopelagic zone

Extends from 200-1000m down

Bathypelagic zone

Extends from 1,000 to 4,000m down

Abyssal zone

Extends from 4,000 to 6,000m down

Hadal zone

Anything below the abyssal zone of 6,000m down

Benthic

Habitats on the bottom of the ocean regardless of water depth

Pelagic zone

Habitats off the bottom of the ocean regardless of depth

How much light is absorbed in the first 10m

80%

What wavelengths of visible light remain at 50-60m

Blue and violet light

Thermal stratification

Layers of warm water on top of layers of cold water

Thermocline

The area of thermal stratification where different temperature waters mix creating sharp temperature changes

Salinity

Amount of salt dissolved in water, average ~35%

Phytoplankton

Microscopic plants that drift to ocean currents in the photic zone

Zooplankton

Microscopic animals that drift to ocean currents

Coral

A filter feeding jellyfish relative that grows a calcium carbonate skeleton underneath creating entire ecosystems for life

fringing reef

Coral reefs that engulf the shores of a young island

Barrier reef

A coral reef that spreads out from a sinking island

Atoll

A coral reef that takes over the shallow area an underwater island

Coral and kelp ranges

Coral reefs are only found in tropical regions while kelp forests are only found in tropical regions

What causes the tides

The gravitational pull of the moon and the sun, strongest tides are when both pull in the same direction

Supertidal fringe

Exposed to mostly air, only the highest tides reach

Upper intertidal zone

Exposed to water for a couple hours a day

Middle intertidal zone

Has large amounts of time out of and under water

Lower intertidal zone

Rarely exposed to air, only the lowest tides would lower sea level enough

Subtotal zone

Below the tides reach, never exposed to the air

Why can oxygen and salinity percents in tide pools vary so much

Intense tides cause mass turbulence which diffuse oxygen in and water out (causing high salinity). However, more protected tide pools experience less variance

Zonation of species

Some species are better equipped for different pressures than others, causing populations to be found in specific areas

Estuaries

brackish water where rivers meet that sea

Salt marshes

Flat grasslands where tides periodically flood

Mangrove forests

Vegetation along coasts that are adapted to turbulent tidal conditions

Mangroves and salt marsh ranges

Mangroves are only found in the tropics while salt marshes are mostly found in temperate areas

Stream orders

First order steams are the head waters, second order streams are formed from 2 first order streams and so on, when streams Sam orders meet, they make a higher order stream. When streams of different orders meet, the highest order takes over but doesn’t increase.

Stream lengths

Pools, runs, riffles and rapids

Stream widths

Wetted and active channels

Stream depth

Water column and benthic zone (benthos)

Hyporheic zone

Transition between surface waters and ground water

Phreatic zone

Below the hyporeic zone

Riparian zone

The transition between aquatic environments and terrestrial environments

Flood pulse

Natural flooding brings/increases nutrients.

Allochthonous

Originates from a different environment

River continuum concept

Upstream canopy covered water transfers plant matter downstream to wider/less covered waters where photosynthesis can occurs

COPM

Coarse organic particulate matter

FOPM

Fine organic particulate matter

Shredders

Aquatic invertebrates that chew plant matter into COPM

Grazers

Aquatic invertebrates that chew COPM into FOPM

Collectors

Aquatic invertebrates that collect FOPM as food

River ecosystem synthesis

The idea that the river continuum model occurs multiple times throughout a stream

Lake litoral zone

Shallowest section Where rooted aquatic plants grow

Limnetic zone

The open lake

The epilimnion zone

The surface layer of lakes

The Metalimnion zone

below the epilimnion zone, this is where you find the thermocline

The hypolimnion zone

The cold dark lake water below the thermocline

What percent of the words freshwater is located in the Great Lakes?

20%

Oligotrophic

Well mixed lakes of low biological production that are well oxygenated

Eutrophic

Lakes with gh biological production but low/depleted oxygen

Lake turn over

Lakes can’t mix when thermally stratified. Most mixing occurs in cold months before the ice cover. This is where wind drives lake turn over

Where did zebra muscles come from

balas water and hulls of cargo ships