Intro to Ecology

Ecology

• Ecology is the study of organisms and their interactions with the environment.

Biomes and Biosphere

• Biomes are large groups of similar ecosystems containing certain organisms.
• The biosphere is the region of Earth that supports life.

Ecosystem Structure

• Ecosystems consist of living (biotic) and non-living (abiotic) components.
• Examples of ecosystems include forests, deserts, oceans, lakes, and backyard gardens.
• Decomposers break down complex organic compounds into simpler nutrients that can be used by producers as food.

Populations and Communities

• A population is a group of individuals of the same species that live in a specific area.
• A community is a group of many populations of different species that live and interact in one environment.

Interactions

• Symbiosis is the type of interaction that takes place when one species lives in close association with another species over a period of time.
• Examples of symbiosis include mutualism (both benefit), commensalism (one benefits, the other is not affected), and parasitism (one benefits, the other is harmed).
• Predation is an interaction in which one species feeds on another.

Succession

• Primary succession begins in a place without any soil, such as the sides of volcanoes, landslides, or flooding.
• Secondary succession begins in a place that already has soil and was once the home of living organisms, such as after forest fires.

Limiting Factors

• Density-dependent limiting factors affect population growth only when the population is high.
• Density-independent limiting factors affect population growth regardless of the population size.
• Examples of density-dependent limiting factors include space, disease, and food, while examples of density-independent limiting factors include weather, human activities, and natural disasters.

Population Growth

• The growth rate of a population is determined by the combined effects of birth rate, death rate, immigration, and emigration.
• When the birth rate and death rate of a population become roughly equal, the population plateaus (levels out).
• Organisms compete for resources such as food, water, space, and mates.

Stars and Stellar Life Cycle

• Sirius is the brightest star in the night sky due to its apparent magnitude.
• The coolest stars appear red in color.
• Polaris is also known as the North Star.
• Binary stars are two stars orbiting each other.
• A light year is the distance light travels in one year.
• A star's color is determined by its surface temperature.

Stellar Evolution

• The life cycle of a star: Nebula → Main Sequence → Giant → Supergiant → Supernova → Planetary Nebula → White Dwarf/Neutron Star/Black Hole
• Fusion is the process by which stars produce energy, combining light elements into heavier elements to produce heat and light.
• The Sun will ultimately form a white dwarf after the outer layers are blown off at the end of its life.

The Sun

• The Sun is a G-type star.
• The Sun's average distance from Earth is 93 million miles.
• The Sun's energy production occurs through fusion, combining hydrogen into helium.
• The Sun's core will eventually run out of hydrogen, causing it to become a red giant and then a white dwarf.

Sun's Features

• Granulation: the Sun's surface texture
• Prominence: huge arching columns of gas
• Solar flare: a sudden release of energy on the Sun's surface
• Sunspot: a cooler area on the Sun's surface
• Solar wind: a stream of charged particles emitted by the Sun

Other Celestial Bodies

• A galaxy is a large group of stars, gas, and dust held together by gravity.
• Light years can be used to measure the relative distances to nearby stars.
• Absolute magnitude measures a star's actual brightness, while apparent magnitude measures its brightness from Earth.

Planets

• Earth is the only known planet to support life.
• Venus has a runaway greenhouse effect due to its atmosphere's high carbon dioxide levels.
• Mars has the largest mountain in the solar system, Olympus Mons.

Earth's Motions

• Rotation: the spinning of an object (Earth) on its axis, taking 24 hours to complete.
• Revolution: the movement of a planet (Earth) around the Sun, taking 365 days to complete.
• Ellipse: the oval shape of Earth's orbit around the Sun.
• Eclipse: the shadow of a planet or moon falling on another celestial body.

Moon and Seasons

• Solstices: the days with the lowest (winter) and highest (summer) sun angles above the equator.
• The phases of the moon change as it orbits the Earth.
• The far side of the moon is not always dark, as it experiences day and night like Earth.

Heat Transfer

• Convection: the flow of a heated substance (e.g., warm air rising).
• Conduction: the movement of heat through direct contact (e.g., walking on hot sand).
• Radiation: heat transfer through open space (e.g., feeling the warmth of the sun).

Climate Controls

• Latitude: Higher latitudes are colder, with the poles being cold and the equator being warm.
• Elevation: The higher the elevation, the colder it gets.
• Topography: Mountain ranges have cooler and wetter conditions on the windward side and warmer and drier conditions on the leeward side.
• Bodies of Water: Water moderates temperatures, resulting in warmer winters and cooler summers.
• Circulation in the Atmosphere (Global Winds): Global winds bring humidity and temperatures with them, where winds from the north bring cooler air, from the south bring warmer air, from the ocean bring humid air, and from continents bring dry air.
• Vegetation: Heavy vegetation can make it more humid.

Characteristics of Climate

• The two main characteristics of an area's climate are temperature and precipitation.

Seasons

• The tilt of Earth's axis (23½°) and its revolution (orbit) around the sun cause Earth to receive both direct and indirect radiation throughout the year, resulting in seasons.
• A common misconception is that seasons are caused by the Earth being closer in summer and farther in winter, which is false.

Weather Phenomena

• Doldrums: Low pressure and low wind along the equator.
• Jet Stream: Narrow belts of strong winds located in the upper troposphere.
• Sea Breeze: A convection current that blows wind from the cooler sea toward warmer land during the day.
• Land Breeze: At night, air moves toward the water as land cools more rapidly than water.

Severe Weather

• Hurricane: Needs warm water to provide energy.
• Tornado: Twisting grey funnels of wind extending from a cloud.
• Blizzard: A huge snowstorm.
• Thunderstorm: CHARACTERIZED by intense lightning and loud noise.

Atmosphere Vocabulary

• Convection: Energy transfer when hot air rises and cold air sinks.
• Condensation: Change from a vapor to a liquid.
• Conduction: How energy is transferred to your feet from a hot beach.
• Evaporation: Change from a liquid to a vapor.
• Infiltration: Not mentioned.
• Ozone: A layer of the atmosphere that contains the ozone layer.
• Precipitation: Formation of water droplets in the atmosphere.
• Radiation: Energy transfer by waves or rays.
• Stratosphere: A layer of the atmosphere that contains the ozone layer.

Layers of the Atmosphere

• Thermosphere: Gets warmer, topmost layer.
• Mesosphere: Gets colder, above the stratosphere.
• Stratosphere: Gets warmer, above the troposphere.
• Troposphere: Gets colder, lowest layer.

Clouds

• Cumulous: Look like fluffy cotton balls with flat bases.
• Stratus: Flat, low layered clouds.
• Cirrus: High altitude icy clouds that look feathery or wispy.
• Nimbus: Dark rain cloud.

Air Rise and Cloud Formation

• Heated air expands and becomes less dense, causing it to rise.
• As it rises, it cools, and if it cools enough, it can reach the dew point and form a cloud, and even precipitation.

Dew Formation

• Air cools down to the dew point, causing condensation (dew) to form on surfaces.
• The cold glass causes the air just outside the glass to reach the dew point, forming droplets on the outside of a cold glass.

Fronts

• Cold Front: Fast moving, can produce stronger storms with higher winds, maybe hail.
• Warm Front: Slower moving, slow steady precipitation for a day or so.
• Occluded Front: Possibly slow steady precipitation.
• Stationary Front: Possibly slow steady precipitation for a few days or more.

Energy Transfer

• Convection: The flow of a heated substance.
• Conduction: How energy is transferred to your feet from a hot beach.
• Radiation: Energy transfer by waves or rays.

Atmospheric Processes

• Conduction: the movement of heat by touch, e.g., walking on hot sand
• Radiation: heat moving through open space, e.g., warmth of the sun on your face
• Convection: the transfer of heat by the flow of a material/fluid, e.g., warm air rising and cooler air sliding in to take its place

Atmospheric Pressure

• The force that air molecules exert on a surface
• Atmospheric pressure at the top of Earth's atmosphere is less dense than at the bottom due to less atmosphere above pushing down

Land and Sea Breezes

• Land breeze: a convection current that blows wind from the cooler sea toward warmer land during the day
• Sea breeze: a convection current that blows wind from the land toward the water at night, as land cools more rapidly than water

Water Cycle

• Energy from the sun evaporates water
• Water vapor rises and cools
• Cooled water vapor condenses
• Clouds form
• Water falls to the earth as precipitation

Wind and Pressure

• Wind forms when air in an area of high pressure moves to an area of lower pressure
• Coriolis effect: the rotation of the Earth causes moving air and water to change direction to the right north of the equator and left south of the equator
• Trade winds: steady winds that blow in tropical regions between the equator and 30° Latitude (north and south)

Ozone and Atmospheric Layers

• Ozone: a thin layer of air that protects the Earth's surface from extreme temperatures and harmful sun rays
• Troposphere: the lowest layer of the atmosphere, containing most of the mass, where humans live, and most of the water vapor and gases
• Stratosphere: the layer of the atmosphere that contains the ozone layer

Severe Weather

• Tornado: twisting grey funnels of wind extending from a cloud
• Hurricane: a huge storm that needs warm water to provide energy
• Blizzard: a huge snowstorm
• Thunderstorm: intense lightning and loud noise are also present

Atmospheric Vocabulary

• Condensation: the change from a vapor to a liquid
• Convection: the transfer of heat by the flow of a material/fluid
• Ozone: a type of oxygen molecule containing three oxygen atoms
• Stratosphere: the layer of the atmosphere that contains the ozone layer
• Radiation: energy transfer by waves or rays