Cycles in Nature Cycles in Nature Many of

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 Eyes – Nocturnal = active during the night • Best suited for: – cool – moist – dark conditions » Very large 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. » 1 st Quarter and 3 rd 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 – 1 st 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 – 3 rd 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!

3 rd Quarter Moon Light on the LEFT!

Waning Crescent Light on the LEFT!

New 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 • 3/4 th 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: O 2 + Glucose = CO 2 + H 2 O + Energy Photosynthesis: CO 2 + H 2 O + Sunlight = O 2 + 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 Simulator

Stages of Ecological Succession 1. Pioneer organisms are the first organisms to reoccupy an area – grasses in a plowed field, lichens on rocks 2. Climax community - final stable community. • can last for hundreds or thousands of years.

Pioneer Organisms Climax Community