Sea Turtles: An Ecological Guide Flashcards

Study Notes

Class and Definition

Sea turtles belong to the class Reptilia, derived from the Latin word meaning "to creep."
Other members of the Reptilia class include crocodilians, snakes, lizards, and dinosaurs.

Shared Characteristics of Reptiles

Possess a vertebral column indicating they are vertebrates.
Feature epidermal scales, which protect internal organs and reduce water loss.
Air-breathing through lungs; unlike fish, reptiles do not have gills.
Ectothermic (cold-blooded), requiring basking for warmth.
Reproduce via internal fertilization, with all sea turtles laying eggs.

Sea Turtle Sizes

Leatherback: 12 feet
Green sea turtle: 4 feet
Loggerhead: 3.8 feet
Hawksbill: 3.2 feet
Olive ridley: 2.8 feet

Evolutionary History

Sea turtles originated in the lower Mesozoic Era, with fossils dating back 112 million years to the middle Cretaceous period.
Land turtles first appeared 200 million years ago, with only two families of the original four still existing today.

Adaptations to Sea Water

Sea turtles are hypo-osmotic compared to seawater, losing water to the ocean.
Their skin and shell resist water diffusion, and they drink seawater.
Specialized salt glands near their eyes excrete excess salt.

Metabolism and Diving

Sea turtles have an adjustable metabolism to extend underwater capacity.
Green turtles can stay submerged for up to 5 hours; hawksbills can manage about 45 minutes.

Anatomy Overview

Plastron: The ventral side of the shell, connected to the carapace via cartilage.
Flippers: Front flippers serve as wings and propellers, while back flippers act as rudders for steering and nest digging.
Cloaca: A structure beneath the tail for excretory and reproductive functions, facilitating internal fertilization.

Shell Structure

Scutes: Keratinous scales over the carapace, which help identify different sea turtle species based on their arrangement.
Carapace: The dorsal part of the shell, fused with backbone and ribs (except leatherbacks).

Circulatory System

Sea turtles have a three-chambered heart, where deoxygenated blood collects in the right atria and is pumped to the lungs for oxygen before returning to the body.

Osmoregulation

Comprised of salt glands and kidneys, the osmoregulatory system manages salt and water balance within the body.

Breathing Adaptations

Sea turtles have multi-chambered lungs, allowing efficient oxygen exchange.
Breathing involves the movement of pectoral and pelvic muscles to compress the lung area, facilitating inhalation and exhalation.
Leatherbacks uniquely store oxygen for deep dives within blood and tissues rather than primarily in the lungs.

Description

Explore the fascinating world of sea turtles and their classification within the Reptilia class through these informative flashcards. Each card presents key characteristics, fun facts, and related reptilian species. Perfect for anyone looking to deepen their understanding of these incredible creatures.