Ecology Exam 1 Fall 2025 BIO2225

Ecology

Study of relationships between organisms and the environment

Ecosystem

Includes all organisms living in an area, and the physical environment with which these organisms interact

Biosphere

Portions of the earth supporting life, highest level of ecological organization

Region

Geographical regions and regional processes; ex. farmland bordering forest where there will be a lot of changes and differences

Landscape

exchange between open ecosystems

Ecosystem

A biological community together with its associated physical and chemical environment; energy flow

Community

An association of interacting species; organisms in an area

Interactions

predation, parasitism, competition

Population

A group of interbreeding individuals of a single species inhabiting a defined area

Individuals

physiological and behavioral ecology

Aeroecology

interdisciplinary study of the ecology of the earth-atmosphere boundary

Urban ecology

the study of urban areas as complex, dynamic ecological systems, influenced by interconnected, biological, physical, and social components

What did Robert MacArthur study in 1958?

The ecology of five species of warblers (birds) in spruce forests in North America

What did MacArthur’s theory predict?

That two species with identical ecological requirements could not coexist indefinitely, the competitive exclusion principle

What did MacArthur’s studies actually show?

Warblers coexisted by feeding in different zones of the same tree

Who climbed the epiphytes (canopy/wall plant mats)

Nalini Nadkarni in 1981

Who monitored plant pollen deposited in lake sediments in the Appalachian Mountains?

Margaret Davis in 1983

Who learned that American Red squirrels conduct earlier breeding when it is warmer in the early spring?

Reale in 2003

Biome

Major divisions of the terrestrial environment

Where are major deserts found?

30 N or S

Functional traits

Particular characteristics that allow them to survive

Selective pressure

The extent to which an organism’s environment influences the fitness of that organism; the force that drives natural selection

Primary producers

Plants and other photosynthetic organisms that can harness energy from the sun

Primary production

Biomass produced by primary producers per unit time

Consumer

Organisms that obtain their energy from eating plants or other organisms

Secondary producers

Organisms that are consumed by other organisms, the energy source for other organisms, cannot harness energy from the sun

Coriolis effect

Causes apparent deflection of winds clockwise in the Northern hemisphere and counterclockwise in the Southern hemisphere

What is the use of the word apparent in defining the Coriolis effect?

The Coriolis effect is only perceived if standing on Earth

Microclimate

When temperature and moisture differ from the prevailing climate

Rainshadow effect

Warm moist air blows towards a mountain range, but will have lost much of its moisture when the air reaches the leeward side

What is the O horizon of soil?

Organic layer of freshly fallen organic material, most superficial layer. Organic material is partially decomposed as you look deeper in the layer. This layer is not found in farmland or deserts and overlaps a lot with A horizon.

What is the A horizon of soil?

Mixture of minerals, clay, silt, and sand (nutrient rich)

What is the B horizon of soil?

Clay, humus, and other materials leached from A horizon, often contains plant roots

What is the C horizon of soil?

Deepest layer, may be rocky like bedrock, contains weathered parent material

Where are tropical rainforests usually found?

Within 10 latitude of the equator

What is true of the soil in a tropical rainforest

It is very nutrient poor

What helps to gather nutrients in a tropical rainforest?

Mycorrhizae

What relationship do mycorrhizae have?

Mutual symbiosis between a fungus’ hyphae and a living plant root

Epiphyte

Plants that grow on other plants and form mats in the tropical rainforest canopies and store lots of nutrients

What is true of the relationship between precipitation and temperature in a tropical rainforest?

Amount of precipitation is higher than temperature

Where are tropical dry forests usually found?

Between 10-25 latitude

What processes are population ecologists studying?

Adaptation, extinction, distribution and abundance of species, population growth and regulation, and variation in reproductive ecology in species

What are community ecologists concentrated on?

Understanding environmental influences on the kinds and diversity of organisms inhabiting an area

What are ecosystem ecologists interested in?

Ecological processes such as energy flow and decomposition

What does the term “in situ” mean?

In the habitat where the organisms live

Where did Nadkarni climb to the forest canopy for research?

Costa Rica and the Pacific Northwest

Who used stable isotopes and genetic analysis to identify trophic relationships for the Anthene usamba (a butterfly)?

Melissa Whitaker in 2019

What does the term “ex situ” mean?

Not in the natural environment

Who studied the importance of bees on the alpine wildflower size and number of seeds?

Candace Galen in 1989

Who studied the growth of algae in lake ecosystems?

Annette Janssen in 2019

What are three general approaches to research?

Observation, experimentation, and modeling

Who developed climate diagrams?

Heinrich Walter in 1985

What is true of tropical dry forest soil?

It is from the ancient continent of Gondwana, richer in nutrients, and vulnerable to erosion

Where are tropical savannas found?

Within 10-20 of the equator

What is true of the climate and plants in the tropical savanna?

There are rains with lightning that start fires killing trees, but grasses regrow quickly

What is true of the soil in the tropical savanna?

It has low water permeability

Where are deserts found?

30 N and S and occupy about 20% of Earth’s land surface

Where does water loss usually exceed precipitation?

desert

What are lithosols?

stone/mineral soil

What is caliche soil?

calcium carbonate-rich hardpan horizon (very salty)

What is true of animal populations in the desert?

There may be lots of different animals, but small amounts of each type

What is true of soil in temperate grasslands?

It is extremely nutrient rich and deep in color

Where can large roaming ungulates be found?

Temperate grassland

Where are temperate forests found?

Between 40 and 50 latitude

What type of plants dominate long growing seasons in temperate forests?

deciduous plants

What type of plants dominate short growing seasons in temperate forests?

Conifers

Which biome is confined to the Northern Hemisphere and covers 11% of Earth’s land area?

Boreal Forest (Taiga)

What is necessary for break down to get nutrients in boreal forest/taiga due to 6 months of winter?

fungi

What is lentic water?

still water

What is lotic water?

moving water

What are limiting resources in water?

oxygen and UV light

What percent of Earth’s surface is covered by water?

71%

What percent of Earth’s water is made up by oceans?

97%

What percent of Earth’s water is made of polar ice caps and glaciers?

2%

What percent of Earth’s water is made up of freshwater sources?

1%

What is the turnover time (required time for entire volume of a reservoir to be renewed) of rivers?

12-20 days

What is the turnover time (required time for entire volume of a reservoir to be renewed) of oceans?

3,100 years

What is the process of wind blowing surface water away from the sore and colder water rising to the surface called?

Upwelling

What is the littoral/intertidal zone?

Shallow shoreline

What is the neritic zone?

Coast to margin of continental shelf

What is defined at the oceanic zone?

Beyond the continental shelf

What oceanic zone is 0-200 m deep?

Epipelagic

What oceanic zone is 200-1000m deep?

Mesopelagic

What oceanic zone is 1000-4000m deep?

Bathypelagic

What oceanic zone is 4000-6000m deep?

Abyssal

What oceanic zone is 6000+m deep?

Hadal

What is the benthic part of the ocean?

Habitat on the bottom of the ocean

What is the pelagic part of the ocean?

Habitat off the bottom of the ocean

What change to light and visuals is noticed beyond 10m deep in water?

Loss of color perception

What change to light and visuals is noticed beyond 50-60 m deep in water?

Blue twilight

What is a thermocline?

A layer of water through which temperature changes rapidly with depth

Where do lowest salinity values occur and why?

Near the equator because precipitation exceeds evaporation

Where is oxygen concentration usually the highest?

Near the ocean surface

What supports high diversity marine communites?

Shallow waters along continents and islands

Where are fringing reefs found?

Hugging the shore of continents

Where are barrier reefs found?

standing between the open sea and lagoon

What are coral atolls?

Coral inlets built up from submerged ocean islands

What is the supratidal fringe of the intertidal zone?

Never covered by high tide

What is the upper intertidal zone of the intertidal zone?

Covered only during the highest tides

What is the lower intertidal zone of the intertidal zone?

Uncovered during lowest tides