Turtle Life Cycle Image from http://www.answersingenesis.org/articles/am/v2/n3/sea-turtles

Turtles are Reptiles What is a Reptile? Most reptiles lay eggs The babies look like miniature versions of the adult Generally, no parental care is given. Babies need to fend for themselves. Ask children to think about what similarities there might be between the life cycles of mammals and reptiles – prompt them with questions such as ‘do reptiles give birth to live young?’ or ‘do reptiles give parental care?’ In reptiles, the female normally lays eggs (Note: some reptiles, including some snake species, give birth to live young). Young reptiles usually look like miniature versions of the adults (i.e. development in reptiles involves growth rather than metamorphosis). Reptiles do not usually give parental care (for instance, sea turtles lay their eggs on land and return to the sea immediately afterwards, and so are not present when the eggs hatch. The young make their own way to the sea, and no food is provided for them). However, in some crocodile species, the female may guard the nest and her young. Reptiles usually reproduce via sexual reproduction, with the male providing the sperm and the female providing the egg. After mating, the female becomes pregnant and lays eggs, completing the life cycle. However, some female reptiles can reproduce without mating with a male – this is known as parthenogenesis, and is a form of asexual reproduction. Reference:   Arkive. (n.d). Turtles. Wildscreen, from http://www.arkive.org/explore/species?q=turtles Image from http://cdn2.arkive.org/media/82/82992D19-36F2-49DE-93C1-B4505C2258D6/Presentation.Large/Western-pond-turtle-hatching-from-egg.jpg

Quick Turtle Facts Turtles live between 40 and 200 years (Sea Turtle Foundation Ltd, 2009). There are over 300 species of turtles around the world with slightly different life cycles (Wikipedia, 2002) Sea turtles have survived for over 120 million years. Their unique life cycle, body shape, strength and tenacity have enabled them to adapt to a constantly changing environment over a period in which many other animals – including dinosaurs – became extinct (Sea Turtle Foundation Ltd, 2008). Turtles can live both on land and in water, as they breathe in both environments.

Basic Turtle Life Cycle Teacher to describe how sea turtle life cycle would differ from other turtles. Since turtles are cold-blooded, they can’t live in places that are cold all year long. But turtles live almost everywhere else. They live in hot, sandy deserts. They live in lush, green forests and grasslands. Some turtles live high in the mountains. Others live in wet, lowland marshes and swamps. Besides living on land, turtles also live in water. Many kinds of turtles live in fresh water, such as in lakes, ponds, or rivers. Sea turtles live in salty oceans. Altogether, there are seven species of turtles that live in the sea. Most kinds live in more than one ocean. Green turtles, for example, live in the Atlantic, Pacific, and Indian oceans Reference: www.animal.discovery.com/reptiles/turtle-info.htm Image from http://www.nzdl.org/gsdl/collect/envl/archives/HASH0192.dir/p063a.gif

Turtles hatch from eggs. The female sea turtle comes onto land to lay her eggs (using hind legs to dig the hole in the sand), while the male spends his entire life in the ocean. The clutch of 50-170 ping-pong ball-like eggs which incubate for 6-13 weeks. They lay between 3-7 nests per season. The mother leaves the nest. The warmth from the sun causes the eggs to hatch. The hatchlings emerge from nest and head towards brightest horizon (Musick & Lawrence, 2003). A variety of factors can affect the hatching success of sea turtles. Such as temperature, natural predators, environmental issues such as plastic bags, fishing nets, oil spills & sand mining (Musick & Lawrence, 2003). Only one in a thousand hatchlings survive the 30-50 years it takes a sea turtle to reach breeding age (Canin & Henkel, 2006).

Turtle Life Cycle Images from: Arkive.org

Sea Turtle Life Cycle Image from: www.sharkbay.org/assets/images/turtle%20breeding%20cycle%20thumb.jpg

Short Video Clips Click here to see part of the turtle life cycle Click here to see turtle eggs hatching

Image from: www.fishpondinfo.com/turtles/turbreed.htm When they are about 40 years old they will come back to the same beach to mate and lay their eggs (Sea Turtle Foundation Ltd, 2009). Some turtles can live to be over 100 years old (Sea Turtle Foundation Ltd, 2009). But some turtles do not even make it past the egg stage. Turn the page to see why……. Image from: www.fishpondinfo.com/turtles/turbreed.htm

Human Threats to Life Cycle Click here to see Turtle eggs moved because of oil spill Image of drawing: Pelf-ism is contagious blog, (2007), from http://chenpn.com/2008/04/08/some-students-can-really-draw/

Factors that affect the Turtle’s Life Cycle Life Cycle Stage Threats to Life Cycle Humans Dogs and Pigs Flooding Egg Artificial light Predators Hatchling Plastic bags Fishing lines Juvenile Fishing lines Hunting/poaching Adult USE THE ARROW KEY TO FILL THE TABLE. After the children have completed the activity, revisit what they have learned from the presentation and from the activity about the different stages of the turtle’s life cycle. Ask the children to name the five main stages in a turtle’s life cycle. Then ask the students to name the various threats turtles face at each stage. Female – lays eggs Male – returns to feeding grounds Polluted beaches Hunting/poaching Noise and light USE THE ARROW KEY ON KEYBOARD TO FILL THE TABLE

References Arkive. (n.d). Turtles. Wildscreen, from http://www.arkive.org/explore/species?q=turtles Arkive. (n.d-a). Giant south american turtle, from http://www.arkive.org/giant-south-american-turtle/podocnemis-expansa/video-09b.html Canin, J., & Henkel, C. (Writers). (2006). One in a thousand. In Hatchling Productions (Producer). Australia. Fordham, D., Georges, A., & Corey, B. (2007). Optimal conditions for egg storage, incubation and post-hatching growth for the freshwater turtle, Chelodina rugosa: Science in support of an indigenous enterprise. Science Direct, 270, 105-114. Musick, S., & Lawrence, L. (2003). Sea Turtle Science. A research-based middle and high school classroom resource. In N. M. E. Association (Ed.), Bridge (pp. 11). Minnesota, USA: National Marine Educators Association. National Geographic Kids. (2010). Gulf turtle eggs relocated, from http://video.nationalgeographic.com/video/player/news/animals-news/us-oil-spill-turtle-relocation-vin.html Sea Turtle Conservancy. (2008). Tour de turtles: A sea turtle migration marathon Retrieved 3rd October, 2010 Sea Turtle Foundation Ltd. (2008). Sea turtle foundation Retrieved 23rd October, 2010 Sea Turtle Foundation Ltd (Writer). (2009). Turtle trials. Australia: Sea Turtle Foundation. SolaMedia. (2009). Turtle: The incredible journey, from http://www.youtube.com/watch?v=somiE24YeHQ&noredirect=1 Wikipedia. (2002). Turtles Retrieved 23rd October, 2010, from http://en.wikipedia.org/wiki/Turtle