Lecture 26 Flashcards
Sponges Have True Tissues:
False
Phylum: Echinodermata: Consist of What?
Sea urchins, starfish, sea cucumbers, and sea lilies.
Echinodermata: Symmetry lasts for how long
Bilaterally Symmertical as larae but not as adults.
How do Echinodermata move?
Move using “tube feet” and sending what to propulse.
Chordates: Share what
All chordates share the same derived sets of characters though some only show traits during embryonic development.
Early Chordate Evolution: What are some traits?
Notochord: Flexible rod that provides support.
Dorsal, hollow nerve cord: Develops into the brain and spinal cord.
Pharyngeal Slits (pharyngeal clefts) that function in suspension feeding, as gills, or as parts of the head.
Muscular tail: That extends posterior to the anus.
If an animal doesn’t possess a hollow nerve cord they have:
A ventral solid nerve cord.
Early Chordate Evolution:
Extant groups of chordates that diverged early in chordate evolution include lancelets and tunicates.
What are Lancelets:
Blade-shaped like the generalized chordate.
What are Tunicates:
Display key chordate traits during their larval stage.
Differences between Lancelets and Tunicates: Main one?
Unlike the lancelets and tunicates, vertebrates have a backbone, a skull, and a well-defined head with a brain and sensory organs.
What is the scientific classification of a jawed vertebrate?
Gnathostomes. There are many more jawed vertebrates than living jawless vertebrates.
Cyclostomes (hagfishes and lampreys):
Jawless fish species, similar lifestyles in terms of ecology.
Cyclostomes (hagfishes and lampreys): Comprise of:
Simple organisms that lack features of other vertebrates.
What does Anadromous mean:
Describing a fish that goes up rivers from the sea in order to spawn.
Sharks, Rays, And Chimaeras: Otherwise filed under class? How many species?
Chondrichthyes, 1,000 species.
Ray-finned fishes, sharks, and rays: Similarities to fish evolution? Shown by how?
Broke off early in fish evolution. Most fish are bony fishes, as sharks and rays don’t have bones instead they have cartilaginous skeletons.
When were Coelocanths rediscovered?
1938 in the Indian Ocean.
Who are the Coelocanths closer related to? Fish or tetrapods?
Coelocanths are closer related to tetrapods and humans than other fish.
Terrestrial Vertebrates: Major event in the colonization of land.
The evolution of limbs feet to lobe-fins gave rise to the amphibians.
Origin of Tetrapods: First ancestor finished skeleton of a fishapod?
Tikataalik. Had both fish and tetrapod characteristics
What do the “fishapod” have?
Fins, gills, lungs, and scales.
Ribs to breathe air and support it’s weight.
A neck + shoulder bones.
Fins with a bone pattern.
Evolution of Fins:
Became progressively more limb-like leading to the development of tetrapods.
Terrestrial Vertebrates: Characteristics
Four limbs support a tetrapod’s weight on land.
Feet with digits for walking.
Neck with vertebrae for independent head movement.
The development of the pelvic girdle to connect the hind legs to the backbone.
Types of Amphibians:
Salamanders “tailed ones”: Class Urodela
Frogs “tailless ones”: Class Anura
Caecillians “legless ones” Classs apoda
Amphibians Traits:
Restricted to damp habitats.
The skin must be kept moist to facilitate gas exhange.
Their eggs lack a shell and desiccation (removal of moisutre).
Declining Amphibian Populations Are Being Caused By What?
Over the past 30 years a disease-causing chytrid fungus, habitat loss, climate change, and pollution.
What Are Amniotes:
Colonized a more extensive range of dry habitats than amphibians.
Tetrapods whose living members include reptiles and mammals.
Parts of the Amniotic Egg: Allantois
A disposal sac for certain metabolic wastes produced by the embryo.
Parts of the Amniotic Egg: Amnion
Protects the embryo in a fluid-filled cavity that cushions against mechanical shock.
Parts of the Amniotic Egg: Chorion
The chorion and the membrane of the allantois exchange gases between the embryo and the air.
Parts of the Amniotic Egg: Yolk Sac
The yolk sac contains the yolk, a stockpile of nutrients, Other nutrients are stored in the albumen.
Amniotes: Key adaptions
The use of a rib cage to ventilate their lungs, no longer need to breathe through the skin. Meaning skins can become less permeable allowing for water conservation.
When did Birds Evolve:
160 Million years ago.
Advantages of flying reptiles.
Escaping earthbound predators. scavenging and hunting.
Enabled long-distance migration for seasonal feeding and breeding.
