Ch. 52 An Introduction to Ecology and the Biosphere

Molloy University General Biology II 1270

What determines where a species live?

• The climate - has the strongest effect on

  • Where terrestrial organisms live.

• Light and nutrient availability are two factors that have a strong effect on

  • where aquatic organisms live

• Dispersal and interactions among organisms also affect where species live

Define Ecology

• is the scientific study of the interactions between organisms and the living and nonliving components of their environment

Name the six levels in the biological hierarchy in both directions

• Organismal ecology

• Population ecology

• Community ecology

• Ecosystem ecology

• Landscape ecology

• Global ecology

Specify organismal ecology

• how an organism’s structure, physiology, and behavior meet the challenges of the environment

• includes physiological, evolutionary, and behavioral ecology

  • Example question: How do flamingos select a mate?

Define population and population ecology:

Population: a group of individuals of the same species living in an area

Population ecology: analyzes factors affecting population size and why it changes over time

• example question: what environmental factors affect the reproductive rate of flamingos?

Define community and community ecology

Community: is a group of populations of different species in an area

Community ecology: examines the affect of interspecific interactions on community structure and organization

• Example Question: What factors influence the diversity of species that interact at an African lake?

Define ecosystem and ecosystem ecology

• Ecosystem: is a community of organisms in an are and the physical factors with which they interact

• Ecosystem ecology: Emphasizes energy flow and chemical cycling between organisms and the environment

  • Example question: What factors control photosynthetic productivity in an aquatic ecosystem?

Define landscape and landscape ecology

• Landscape (or seascape): is a mosaic of connected ecosystems

• landscape Ecology: Focuses on the exchange of energy, materials, and organisms across multiple ecosystems

  • Example question: To what extent do nutrients from terrestrial ecosystems affect organisms in a lake?

Define biosphere and global ecology

• Biosphere - the global ecosystem the sum of all the planet’s ecosystems and landscapes

• Global ecology: Examines how the exchange of energy and materials influences the function and distribution of organisms across the biosphere

Specify Climate

• the long-term prevailing weather conditions in an area constitute its climate

• Climate is the most significant influence on the distribution of organisms on land

• The four major physical components of climate are temperature, precipitation, sunlight, and wind

Specify global climate patterns

• Global climate patterns are determined largely by solar energy and Earth’s movement in space

• The warming effect of the sun establishes temperature variations, circulation of air and water, and evaporation of water

• This causes latitudinal variation in climate

Specify latitudinal variations in sunlight intensity

• The intensity of sunlight- the amount of heat and light per unit surface area-is affected by the angle of impact

• Sunlight is most direct and therefore most intense in the tropics (23.5º north to 23.5º south latitude)

• At higher latitudes, sunlight hits at an oblique angle, making the light energy more diffuse and less intense

Specify global air circulation and precipitation patterns

• Global air circulation and precipitation patterns play major roles in determining climate patterns

• Intense sunlight causes water to evaporate in the tropics, and warm, wet air masses rise and flow from the tropics toward the poles.

• Rising air masses release water and cause high precipitation, especially in the tropics

• Dry, descending air masses create arid climates, especially near 30º north and south

• Air masses ride again at 60º north and south, and release abundant precipitation

• Cold, dry rising air flows to the poles and descends, absorbing moisture and creating dry, cold climate at polar regions.

List the regional and local effects on climate

• Climate varies seasonally and is modified by other factors including large bodied of water and mountain ranges

What causes the seasonality in middle to high latitudes?

• Seasonality in middle to high latitudes is caused by the tilt of Earth’s Axis of rotation and its annual passage around the sun

• Seasonal variations in day length, solar radiation, and temperature increase steadily toward the poles

What causes wet and dry seasons? Where tropical deciduous forest grow?

• The changing angle of the sun over the course of the year affects local environments

• For example, belts of wet and dry on either side of the equator shift as the angle of the sun changes

• This causes wet and dry seasons at 20ºN and 20ºS latitudes, where tropical deciduous forest grow

Specify the effects of the seasonal changes in wind patterns

• Seasonal changes in wind patterns alter ocean currents

• These changes can cause upwelling of cold, nutrients-rich water from deep ocean layers

• The influx of nutrients to surface water stimulates population growth of phytoplankton and the organisms that feed on them

Many deserts are found in ____ of mountains.

• Many deserts are found in the rain shadows of mountains

In the northern Hemisphere, _____ slopes are warmer and drier.

• In the northern Hemisphere, south-facing slopes are warmer and drier because they receive more sunlight than north-facing slopes

Functions and effects of transpiration

• Terrestrial organisms, particularly forests, can alter climate at local and regional scales

• The darker color of forests cause them to absorb more solar energy than deserts or grasslands

• This warming effect is offset by transpiration, which causes evaporative cooling, which reduces surface temperature and increases precipitation rates

• The climate becomes hotter and drier in areas where humans have cut down large forests

• Where humans have restored large forests, the climate becomes cooler and wetter

Define microclimate

• Microclimate refers to very fine, localized patterns in climate

• Many features of the environment influence surrounding areas by casting shade, altering evaporation from soil, or changing wind patterns

• For example, forest trees moderate the microclimate below them

List the four abiotic factors

• Environments are characterized by differences in abiotic, or nonliving, factors such as temperature, light, water, and nutrients

Define climate change

• The burning of fossil fuels and deforestation have increased the concentration of greenhouse gases in the atmosphere

• This has caused climate change, a directional change to the global climate lasting three decades or more

Define biomes

• Biomes are major life zones characterized by vegetation type (terrestrial biomes) or physical environment (aquatic biomes)

Define climograph

• A climograph plots the annual mean temperature and precipitation in a region

• Biomes are affected not just by mean temperature and precipitation, but also by the pattern of temperature and precipitation through the year

What are the terrestrial biomes named for?

• Terrestrial biomes are named for major physical or climate features and predominant vegetation

• terrestrial biomes usually grade into each other, without sharp boundaries

Define ecotone

• The area of intergradation, may be wide or narrow

Specify vertical layering of vegetation

• Vertical layering of vegetation provides diverse habitats for animals in terrestrial biomes

• In a forest, vertical layering may consist of an upper canopy, low tree layer, shrub understory, herbaceous plants, forest floor, and root layer

Define disturbance

• Disturbance is an event such as a storm,, fire, or human activity that changes a community

• For example, frequent fires can kill woody plants and maintain the characteristics vegetation of a savanna

• for example, hurricanes create openings in forest canopies that allow different species to grow

• In many biomes, even dominant plants depend on periodic disturbance

List the four features to describe terrestrial biomes

• distribution

• precipitation

• temperature

• plants and animals inhabit them

humans have altered much of Earth’s surface, and have important impacts in most terrestrial biomes

List the 8 types of terrestrial biomes

1. Tropical Forest

2. Desert

3. Savanna

4. Chaparral

5. Temperate Grassland

6. Northern Coniferous forest

7. Broadleaf Forest

8. Tundra

List the three major impacts of oceans to the Earth

• Oceans have a major impact on the biosphere because they cover about 75% of the Earth’s surface

• Water evaporated from the oceans provides most of the plant’s rainfall

• Photosynthetic marine organisms provide most of the plant’s O2 and consume large amounts of CO2

• Ocean temperatures effect global climate and wind patterns, and moderate the climate of nearby land

List the three factors that stratify aquatic biomes into zones

• Freshwater biomes are strongly influences by the soil and biotic components of the surrounding terrestrial biome

Define photic zone, photic zone, and pelagic zone

• many aquatic biomes are stratified into zones defined by light penetration, temperature, and depth

• The upper photic zone has sufficient light for photosynthesis; the lower aphotic zone receives little light

• The photic and aphotic zones make up the pelagic zone

Define abyssal zone, benthic zone, benthos and detritus

• Abyssal zone is located in the aphotic zone with a depth of 2,000-6,000 m

• The organic and inorganic sediment at the bottom of all aquatic zones is called the benthic zone

• The communities of organisms in the benthic zone are collectively called the benthos

• Detritus, dead organic mater, falls from the surface and forms and important food source for the benthos

Define thermocline

• in oceans and most lakes, a temperature boundary called the thermocline separates the warm upper layer from the cold deeper layer

Specify turnover

• Many lakes undergo mixing of their waters called turnover in the spring and autumn

• Turnover sends oxygenated water from the surface to the bottom and nutrient-rich water from the bottom to the surface

In marine communities, most organisms occur in the ____.

• In marine communities, most organisms occur in the relatively shallow photic zone

____ Zone in oceans is extensive but harbors little life

• The aphotic zone in oceans is extensive but harbors little life

Define dispersal

• Dispersal is the movement of individuals or gametes away from their area of origin or centers of high population density

• Dispersal contributes to the global distribution of organisms