Ecology Midterm 1

Ernst Haekel

coined the term Ecology in 1866

Ecology

The investigation of the total relations of the animal both to

its inorganic and to its organic environment;

Paleoecology

Historical Studies

MacArthur

studied ecology of five species of warblers in spruce forests in Maine

Research Hypothesis

Idea or possible explanation for some phenomenon

Statistical Hypothesis

Test of a prediction from the research hypothesis, relies on construction of null and alternate hypotheses

Induction

Observe and describe phenomena

Deduction

Formulate a research hypothesis or multiple hypotheses. Method of circumstantial evidence.

Null Hypothesis

means the prediction is not true/nothing happened

Alternate Hypothesis

Means the prediction is true

P-Value

Probability that an effect size of the magnitude observed (or larger) would occur by chance

Biological Significance

A function of the effect size, and the question of whether a response or relationship of a particular magnitude is meaningful

Mesurative Study

Some aspect of an organism, population or community is measured without manipulation

Manipulative Study

The researcher attempts to understand an ecological phenomenon by manipulating a particular factor and comparing the response of organisms or a community to an unmanipulated control

Interval and Ratio Scale

continuous (densities, proportions, etc.) or discrete (counts), all have units

Nominal

presence/absence, yes/no, or number of observations in a series of classes

Accuracy

Closeness of a measured value to its true value

Precision

Closeness of measured values to each other

Temperature and Moisture

Primary abiotic factors that shape environment

Terrestrial Biomes

• Large-scale classification of terrestrial habitats

• Distinguished primarily by their predominant plant species

Soil

• Complex mixture of living and non-living components, diverse ecosystem

• Highly variable in attributes such as organic matter, sediment particle size, water content, nutrient content

Tundra, Boreal Forest, Temperate Forest, Temperate Grassland

4 major biomes in Canada

Arctic Tundra

• Most land north of Arctic circle

• Cold, short summers

• Dry, 200-600 mm precipitation

• Soils build slowly, permafrost present

• Plants dominated by grasses, sedges, mosses & lichens.

• Dwarf trees present, all plants are hardy.

• Supports number of large native mammals.

• Highly vulnerable to climate change.

Boreal Forest (Taiga)

• Covers 11% land area, band from 50-65 °N.

• Long winters, short summers, huge temperature range

• Moderate precipitation (200-600 mm)

• Soils tend to be thin, acidic, and not very fertile

• Vegetation is dominated by evergreen conifers, some deciduous trees. Moss and bogs present

• Important habitat for wide range of animal taxa

• Disturbance-driven ecosystem

• Vulnerable to climate changes and exploited by humans – management is critical

Temperate Forest

• Mostly within 40° to 50° latitude

• Moderate temperatures, wide range of precipitation (650-3,000+ mm)

• Fertile soils, especially in deciduous forests

• Both deciduous and coniferous forests present, can be huge biomass

• Vertically stratified based on shade tolerance

• Range of animals present, microbes important for decomposition

• Humans have destroyed most of the old-growth temperate forest throughout the world

Temperate Grassland

• Globally widespread

• Moderate temperatures, 300-1,000 mm precipitation annually, droughts can be persistent

• Soils can be deep and productive

• Dominated by herbaceous vegetation; plants maintain most of their biomass underground

• Supported large herds of herbivores, much diminished now

• Biome is critically endangered, agriculture has dramatically reduced organic matter of soils

Tropical Rain Forest

• Most occur within 10° of equator on 3 continents.

• Warm and wet year-round, annual rainfall ~2,000 – 4,000 mm

• Soils are nutrient-poor, acidic, low in organic matter except in select areas

• Trees dominate, form shallow root systems

• Exceptional diversity of plants and animals exhibiting complex relationships

• Human dependence and exploitation is extreme

80

___% of all Canadians, and > 50% of all people globally live in urban areas

1

Over 70% of the planet is covered in water

• 97% ocean

• 2% glaciers and polar ice caps

• __% fresh water

Oxygen

Major limiting factor in aquatic environments

Hydrological Cycle

Exchange of water among “reservoirs”

3,100

Turnover time varies among reservoirs:

• Atmosphere 9 days

• Rivers 12–20 days

• Oceans _______ years

Open Ocean

• single interconnected mass, 360 million km2.

• Largest biome

• Circulation driven by prevailing winds, currents impact life in water and on land

Intertidal (Littoral) Zone

Shallow shoreline; tidal influence

Neritic Zone

Coast to margin of continental shelf

Oceanic Zone

Beyond continental shelf; divided into vertical zones

Benthic

Habitat on bottom

Pelagic

Habitat off the bottom

Salinity

• Amount of salt dissolved in water, in open ocean is 34 - 36.5 parts per thousand

• varies with ratio of precipitation to evaporation

Increases

Oxygen concentration is highest near ocean surface, and decreases with depth down to ~1000 m, then ________ again

Phytoplankton

• form the base of a food web that supports all ocean-dwellers

• ¼ of all photosynthesis in the biosphere

Light

What limits photosynthetic organisms?

Endemic

Naturally occurring in only a single environment

Shallow Marine Water

• Highly diverse and productive communities

• Based on kelp in temperate areas and corals near the equator

Kelp Forests

• offer 3-D habitat structure similar to terrestrial forests

• Can extend >25 m from sea floor

Coral Reefs

can form as barriers, fringes, or atolls – in all cases offer a complex habitat supporting great species diversity

Riparian Zone

Transition between the aquatic environment of the river and the upland terrestrial environment

Hyporheic Zone

transition between areas of surface water flow and groundwater

Phreatic Zone

Ares containing groundwater below the hyporheic zone

Stream Order

Classification of streams and rivers by where they occur in a drainage network

River Discharge

The amount of water carried by rivers

Flood Pulse Concept

describes how the annual rise and fall of river water levels drives ecological processes in river-floodplain systems by connecting the river to its floodplain

Biochemical Oxygen Demand (BOD)

A measure of organic pollution defined as the amount of dissolved oxygen required by microbes, to decompose the organic matter in a water sample

River Continuum Concept

theory proposing that river ecosystems exhibit predictable, continuous changes in physical and biological attributes from headwaters to the ocean

Lake Baikal

the world's largest, oldest, and deepest freshwater lake, holding 20% of the planet's unfrozen freshwater supply

Limnetic Zone

Beyond the littoral zone in the open lake

Epilimnion

Encompasses the surface layer of lakes

Metalimnion

• Below the epilmnion

• Zone through which temperature changes substantially with depth - generally 1C per meter

Hypolimnion

• Below the thermocline

• Cold, dark water

Oligotrophic

• Well-mixed lakes of low biological production

• Well oxygenated

Eutrophic

• Lakes of high biological production

• May be depleted of oxygen

Omnivores

Eat a wide range of food

Insectivores

Feed on insects

Piscivores

Feed on other fish

Temperature

Measure of the average kinetic energy of the molecules, in a mass of a substance

Macroclimate

The prevailing weather conditions in a region over a long period of time

Microclimate

Climate variation on a scale of a few kilometres, metres, or even centimetres, usually measured over short periods of time

Riparian Vegetation

Vegetation that grows along rivers and streams

Intertidal Zone

Area between high and low tide lines

Supratidal Fringe

Only covered during very high tides

Estuary

Where rivers flow into sea - salt and fresh water merge

Salt Marsh

Transition zone from sea water to land, concentrated along low-lying coast in sandy/muddy areas

Salt Pan

Small basin in marshes that retains water when the tide recedes

Salt Marshes

Extremely important nursery habitat for fish and critical environment for many birds

Principle of Allocation

an organism possesses a finite amount of resources (like energy) which must be divided among various conflicting life processes, such as growth, reproduction, and survival

Law of Tolerance

Distribution and abundance of species depends on deviation between local conditions and optimal conditions for species

Adaptation

Heritable trait that maintains or increases the fitness of an individual under a given set of conditions - assume to be the result of Natural Selection

Fitness

The relative contribution of an individual in a population towards future generations

Ecotypes

Individuals with genetically determined differences between populations within a species that reflect local matches between the organism and its environment

Acclimation

• “Adaptation” within an organism’s lifetime

• Can be seasonal or short term, or long term

Principle of Allocation

Energy allocated to one function reduces amount for other functions - you can’t be good at everything

Poikilothermy

Body temperature varies directly with environmental temperature

Homeothermy

Maintain a relatively constant internal temperature

Endothermy

Rely heavily on metabolic energy to heat body or critical organs

Ectothermy

Rely mainly on external energy sources and behaviour to regulate internal temperatures

Ectotherms

metabolic rates mostly increase with temperature

Plants

Can acclimate to local conditions and adjust photosynthetic rates accordingly

Microbes

can be very temperature-adapted, exhibiting active metabolism and reproduction in highly different environments with different thermal ranges

Arctic Plants

• maximize heat absorption and minimize loss through evolutionary adaptations

• increase heat gain through colour, leaf orientation, and ground hugging

• decrease heat loss through wind

Desert Plants

• Minimize heat intake and maximize its loss without increased evaporation

• decrease heat gain through colour, leaf orientation, and tall open growth style

• increase heat loss through wind

Skunk Cabbage

stores large quantities of starch in root, and then translocate it to the inflorescence where it is metabolized, generating heat

Araceae

use metabolic energy to heat flowers

Ectothermic Animals

• Use external sources of energy to regulate body temperature

• Make use of pigmentation, body size and shape, and behaviour

• Basking in the sun and seeking shade are common

Endothermic Animals

• Use metabolic heat to regulate body temperature, as well as various behavioural and morphological adaptations

• Have more challenges cooling off, so require additional adaptions to dissipate metabolic heat (e.g. panting, sweating, large extremities)

Aquatic Endotherms

• Use countercurrent heat exchange to maintain body temperature

• Blubber insulates the body, and countercurrent heat exchange reduces heat loss from the extremities

Death, Migration, Resistance

Strategies for coping with cold

Migration

Very costly, but common among species at high risk from extreme temperatures

Resistance

• Fur, fat feathers (birds and mammals)

• Acclimate (many plants)

• Avoid - e.g. burrow, seek shelter

• Possess anti-freeze proteins (some insects, fish)

• Allow yourself to freeze

• Hibernation

Estivation

prolonged torpor or dormancy of an animal during a hot or dry period

Torpor

short-term reduction in metabolic rate