ENVIRONMENTAL SCIENCE SSI Unit 2 Lion Fish Tegus

ENVIRONMENTAL SCIENCE SSI Unit 2 Lion Fish, Tegus, and Burmese Pythons, Oh My!

ENVIRONMENTAL SCIENCE SSI Unit 2. 3 Explaining the Roles Species Play Explicando el Rol que las Especies juegan

SSI Unit 2. 3 Objectives Students will be able to do the following: 1. Describe how a species fills a niche within its ecosystem. 2. Explain how ecologists classify keystone and indicator species. 3. Understand how threats to keystone species and indicator species in turn threaten the ecosystems they inhabit. 4. Refine their positions on the issue of the eradication of invasive species.

Lesson 2. 3 Explaining the Roles Species Play Engage: Keystone Species (Especies Claves) What is the most important stone in and arch? Cual es la piedra mas importante? Why? Porque sostiene el arco para que no se desplome.

What do you think happens when a keystone species is removed from an ecosystem? Que tu crees puede suceder cuando una especie clave es removida de un ecosistema? Gopher tortoises are known as a keystone species. The Florida Fish and Wildlife Conservation Commission states the gopher tortoise burrows provides refuge for as many as 350 to 400 species. Esta tortuga es una especie clave- provee refugio a mas de 400 especies debido a los hoyos (casas) q crean en la tierra.

The niche (or role) (el rol, trabajo) that the Gopher tortoise occupies is as a consumer and a burrower. What is a consumer? Que es un consumidor? What is a burrower? Que es un excavador?

What is YOUR niche within the ecosystem? Cual es tu niche (rol) dentro del ecosistema?

AMERICAN ALLIGATORS COCODRILOS

While you are reading the text, answer the following questions in your Notebook. Copy the questions… • Why is the American Alligator considered a keystone species? Porque es el Cocodrilo Americano considerado una especie clave? • How would the disappearance of a keystone species lead to the collapse of an ecosystem? Como la desaparicion de una especie clave puede ocacionar que un ecosistema colapse?

Adult male (macho adulto) alligators occasionally reach 13 to 15 feet (pies) in length (longitud). Maximum length for females (hembras) is approximately 10 feet. Both sexes tend to be smaller in South Florida. The snout of an alligator is characteristically broad, although the shape can vary slightly (su forma es variada) among populations and individuals. The bright yellow cross-bands that juvenile alligators sport against a black background provide effective camouflage (bandas amarillas proveen camuflaje) The yellow banding fades away as the juveniles mature.

Juveniles (juveniles) eat (comen) a wide variety of small invertebrates (invertebrados), particularly insects (insectos), as well as small fish (peces) and frogs (ranas). The adult (adulto) diet typically consists of fish, turtles, small mammals (mamiferos), birds (pajaros), and reptiles (reptiles), including small alligators. The color of adult alligators varies with habitat and can be olive (color oliva), brown (marron), gray (gris), or nearly black (negro), with a creamy underside. Algae-laden waters produce greener skin, while tannic acid from overhanging trees can produce darker skin.

Female alligators choose nest (nido) sites above the water level (por encima del nivel del mar) to reduce the chance of flooding (inundacion), which would kill most eggs within 12 hours of submergence. Completed nests are about 3. 5 feet high and twice as wide. Females remain near (cerca) the nest during the incubation period, which averages 58 to 63 days. When danger (peligro) threatens, she will rapidly return (regresa) to the nest to protect her eggs.

The temperature (temperatura) at which the eggs (huevos) develop (desarrollan) determines (determina) the sex (sexo) of the hatchling. Eggs that incubate at temperatures ranging from 90 to 93 degrees (grados) Fahrenheit hatch as males, while those that incubate from 82 to 86 degrees (grados) hatch as females. Intermediate temperature ranges yield a mix of both male and female hatchlings.

The nesting activity of female alligators is important for the creation of peat. Several turtle species (algunas tortugas), such as the Florida redbellied turtle (Chrysemys nelsoni), incubate their eggs inside both active and old/abandoned alligator nests. (incuban sus huevos en nidos abandonados o activos) Water remains in alligator holes (el agua se mantiene en los hoyos) throughout the year except during severe drought conditions. As the dry season approaches and water dries up from other areas within the Everglades, the retained water causes alligator holes to become a refuge for a variety of wildlife. (Entonces los hoyos se vuelven un refugio parta otros animales cuando es tiempo de sequia)

Although these animals become easy prey (presa facil) for alligators and other predators such as wading birds, the value of the refuge outweighs the risk. Human conflicts with alligators are rare and generally not serious, but incidents do occur and have been reported. Education and awareness is the best long-term way to avoid future incidents. Most alligator attacks on humans are attributed to the illegal feeding of alligators, (muchos ataques de cocodrilos hacia los humanos ocurren porque las peronas illegalmente los alimentan) which makes them bolder, less wary of humans, and more likely to attack instead of flee. It is illegal to feed or provoke alligators as well as all other wildlife (es illegal alimentar a cualquier animal salvaje).

While you are reading the text, answer the following questions in your Notebook. Copy the questions… • Why is the American Alligator considered a keystone species? Porque es el American Alligator considerado una especie clave? • How would the disappearance of a keystone species lead to the collapse of an ecosystem? Como la desaparicion de una especie clave puede hacer que un ecosistema colapse?

Dwindling populations (disminucion de la poblacion) of alligators were the result (resultado) of hunting and loss of habitat, (caza y perdida de habitat) and the American alligator was listed as an endangered species (especie en peligro de extinction) in 1967 under a law that preceded the Endangered Species Act of 1973. The number of alligators began (comenzo) to rebound (a restaurarse) when alligator farms (granjas de cocodrilos) opened and hunting was outlawed, easing the pressure on wild populations.

However, even after hunting was prohibited in Florida, illegal poaching (caza o destruccion illegal) continued into the 1970 s because the belly skin (piel) of alligators produces high-quality leather (cuero). Were it not for additional changes in the law controlling the movement of alligator hides, extinction may have been possible. Populations have since improved considerably, and alligators were removed (removidos) from the list of endangered species in 1987 and are continuing to thrive in Florida today.

AN EXAMPLE OF WHAT YOU SHOULD NOT DO (LO QUE NO DEBES HACER)

Explore: Wood Stork While you are reading the text, answer the following questions in your Notebook. Copy the questions • How is the wood stork affected by changes in the hydrologic cycle? Como es la cigueña afectada por cambios en el ciclo hidrologico? • Why is the wood stork considered an indicator species? Porque la cigueña es considerada un especie indicador? Why has the wood stork move to other places like Georgia and South Carolina? Porque la cigueña se ha mudado a lugares como Georgia y Carolina del Sur?

The feeding behavior (comportamiento alimenticio) of Wood Storks (cigueña) has evolved (ha evolucionado) over many thousands of years to reflect the natural conditions of the Everglades. When the natural hydrologic cycle (ciclo hidrologico) is upset (afectado)by human (humano)-controlled watermanagement activities, Wood Storks fail (fallan) to feed (alimentarse) and nest (hacer nidos) successfully because a breeding pair of Wood Storks will not attempt to nest if sufficient food is not available (ellos no trataran de poner huevos si no hay suficiente comida). Hydrologic conditions resulting from water-management activities in recent years often have been unfavorable to support Wood Stork feeding and nesting requirements.

The Wood Stork serves (sirve) as an indicator species (especie indicadora) for restoration (para la restauracion) of the Everglades ecosystem (ecosistema). Indicator species serve (sirven) as excellent messengers (mensajeros) of the past (pasado), present (presente), and future (futuro) because their specific habitat requirements (debido a sus necesidades especificas)are so closely associated (asociadas) with one particular environment (con un ambiente particular).

The quality (calidad) and quantity (cantidad) of the required environment (ambiente) directly determines (determina) the well -being (cuan saludable) and the number of that species (la cantidad). Because it is much easier (mas facil) to count (contar) and record (registrar) the biology (la biologia) of one or more (de una o mas) indicator species (especies indicadoras) than it is to measure the more complex workings of an ecosystem (que medir un ecosistema complete), close monitoring of carefully selected species provides important information about the health of the entire system.

Modern water-control programs (programas de control de agua) in south Florida have so greatly changed (han cambiado) the flooding (inundaciones) and drying patterns (patrones de sequia) of the Everglades that the survival (la sobrevivencia) of Wood Stork nesting colonies is in question (esta siendo cuestionada). Accelerated development of water-control structures and unnatural water-delivery schedules in the 1960 s has sharply (reducido) the number (numero) of birds (pajaros) since that time. By 1995, fewer than (menos de) 500 pairs (pares) of (de) Wood Storks were nesting in the Everglades National Park and Big Cypress National Preserve area of south Florida. If recent trends continue (si esto continua), Wood Storks may no longer be able to survive (sobrevivir) in south Florida. The dwindling population (la disminucion de la poblacion) of Wood Storks in south Florida does not mean that the species is going extinct (no se esta extinguiendo), but that they have moved (mudado) to more suitable habitat in other locations such as north Florida, Georgia, and South Carolina.

• What does the term, indicator species, mean? Reread paragraph to answer The Wood Stork serves as an indicator species for restoration of the Everglades ecosystem. Indicator species serve as excellent messengers of the past, present, and future because their specific habitat requirements are so closely associated with one particular environment. The quality and quantity of the required environment directly determines the well-being and the number of that species. Because it is much easier to count and record the biology of one or more indicator species than it is to measure the more complex workings of an ecosystem, close monitoring of carefully selected species provides important information about the health of the entire system.

Explain: Comparing and Contrasting American Alligators and Wood Storks Refer to the text again, in order to compare and contrast (comparar y contrastar) keystone species and indicator species. Record your findings in a Venn diagrams.

Elaborate: Refine Vote You have explored the meaning of biodiversity and the impact of the addition of an invasive species on an areas biodiversity index. Readdress the unit question: Should we eradicate invasive species? Deberiamos erradicar las especies invasivas? Adjust your previous votes, with regard to the unit question by moving one of the sticky notes from ‘yes’ to ‘no’ or vice versa. “Have you changed your vote? Why or why not? ” Cambiaste tu voto? Si o No y porque?