Cycles in Nature

Cycles in Nature Many of the daily, monthly and seasonal changes that take place on Earth are patterns that occur over and over – Rhythms. Types of Rhythms: Day into night = daily rhythm Rise and fall of tide = daily & monthly rhythms Lunar phases = monthly rhythm Changing of seasons – annual rhythm

Daily Rhythms Day/Night Cycles: Earth rotates (spins) on it’s axis 1 rotation – 1 day or 24 hours spins from West to East Sun rises in the East and sets in the West. Half of the earth is always lit! Earth’s Rotation Simulator www.georgefcram.com/

Affects of Daily Rhythms Diurnal Eyes Organisms adapt many of their daily activities around day/night cycles. Diurnal = active during the day Best suited for: warm dry bright conditions Nocturnal = active during the night cool moist dark conditions Very large eyes Nocturnal Eyes library.thinkquest.org/

Tides – Daily Rhythms Earth has a natural satellite, the moon, that revolves (orbits) around it. The moon has a gravitational pull that affects the location of water on Earth. Tide Simulator

Tides The Earth rotates, spins, once in 24 hrs which means that the Earth moves into and out of a tidal bulge once every 6 hours. Creates: 2 high tides daily 2 low tides daily.

Tides – monthly rhythms The moon revolves, orbits, around the Earth once every 27.3 days Affect monthly tide cycles too. If the moon is in a straight line with the sun and Earth it causes higher than normal high tides – Spring Tides. Both the moon’s and sun’s gravitational pull are acting on Earth’s waters. Full moon and New moon If the moon is at a right angle to the Earth and sun it causes lower than normal high tides – Neap Tides. The sun’s gravitational pull cancels out the moon’s gravitational pull. 1st Quarter and 3rd Quarter

Spring Tides www.redfishpro.org

Neap Tides www.redfishpro.org

The Moon – Monthly Rhythms Moon revolves around the earth Earth’s only satellite! 1 revolution – 1 month or 27.3 days Moon also rotates on its axis 1 rotation = 27.3 days Rotation = Revolutions 1 day = 1 year Same side of the moon always faces the earth!

Moon’s Orbit scssi.scetv.org/

Moon Phases As the moon revolves around the earth the amount of lit surface, visible from earth, is always changing. Waxing phases – lit surface is increasing Light on the right! Waxing Crescent 1st Quarter Waxing Gibbous Full Moon – full lit surface facing earth

Moon’s Phases Waxing Phases (Light on Right!) www.astro.virginia.edu/

Waxing Crescent Light on the RIGHT

First Quarter Moon Light on the RIGHT

Waxing Gibbous Light on the RIGHT

Full Moon

Moon Phases Waning phases – lit surface is decreasing Light on the left! Waning Gibbous 3rd Quarter Waning Crescent New Moon – no lit surface facing earth

Moon’s Phases Waning Phases (Light on Left!) www.astro.virginia.edu/

Waning Gibbous Light on the LEFT!

3rd Quarter Moon Light on the LEFT!

Waning Crescent Light on the LEFT!

New Moon Moon Phases Simulator

Annual Rhythms The Earth: Earth revolves around the sun 1 revolution – 1 year or 365 days Earth is tilted on it’s axis – 23.5° Seasons occur because of the direction of the tilt!

Seasons www.georgefcram.com/

Affects of Environmental Rhythms Organisms can only survive in a habitat if all conditions needed for survival are met. As different cycles in nature start to affect an organism’s survival they need to either adapt or move. Breeding Seasons Hibernation Estivation Migration

Breeding Seasons Organisms time the birth of offspring for when seasonal conditions are best for the survival of the offspring. Longer gestation period: Pregnant through the more difficult seasons, fall & winter, and deliver when conditions are best, spring & summer. Deer - Breed in fall and birth in spring Shorter gestation period: Pregnant just as conditions are turning for the better and deliver as they reach their peak, spring & summer. Geese – breed in spring and hatch in spring.

Hibernation & Estivation Hibernation – sleep through the seasons that can’t support needs, winter months. Bears & groundhogs Estivation – spend the hottest and driest portion of the day inactive. Snails, reptiles & lions

Migration If organisms aren’t able to survive during difficult conditions they may move to better locations that can support their needs – Migration. Hummingbirds, Monarch Butterflies, Wildebeest, Whales.

Environmental Cycles The Earth also experiences natural cycles that affect the survival of organisms. Water Cycle Carbon/Oxygen Nitrogen Ecological Succession

Water Cycle 3/4th of the planet is cover by water Water is continuously circulating between surface and atmosphere. Not a predictable pattern but random.

Cycles in Nature Evaporation – liquid water to gas Occurs with presence of heat Condensation – gas to liquid droplets Cooler conditions Dew and formation of clouds Precipitation – water falling back to earth Rain, snow, sleet or hail Infiltration - Water being absorbed into the soil Groundwater – water being stored in the ground aquifers Runoff – freely flowing water on the ground. Rivers, streams

Carbon/Oxygen The exchange of carbon dioxide and oxygen between animals and plants. Respiration: O2 + Glucose = CO2 + H2O + Energy Photosynthesis: CO2 + H2O + Sunlight = O2 + Glucose

Nitrogen Cycle 78% of the atmosphere is Nitrogen (N) Needed by all living things but cannot be obtained through the air we breathe! Nitrogen Fixation – bacteria use free nitrogen to make nitrogen compounds in the soil. Nitrates can then be used by organisms when they eat plants.

Ecological Succession The gradual long term changes in altered ecosystems. Ecosystems tend to change until a stable system is formed. The type of succession depends on climate (temperature & precipitation) and other limitations of a given area. Can be sped up or slowed down Sewage = aquatic plants grow faster Plowing, fire, and floods = slow down succession Succession Simulator

Stages of Ecological Succession Pioneer organisms are the first organisms to reoccupy an area grasses in a plowed field, lichens on rocks Climax community - final stable community. can last for hundreds or thousands of years.

Pioneer Organisms Climax Community