What are the 4 phyla of deuterostomes?
Body plan of Phyla Echinodermata
bilaterally symmetric as larvae then radially symmetric as adults (specifically 5 planes of symmetry), podia, water vascular system, endoskeleton of calcareous ossicles
What are synapomorphies of Echinoderms?
water vascular system, 5-pointed symmetry, calcareous ossicles on endoskeleton, connective tissue can be rapidly altered via the nervous system (mutable)
Feeding in Phyla Echinodermata
suspension feed, deposit feed [use podia], or harvest algae or other animals [sea stars can open bivalves], Aristotle's Lantern (mouth located on ventral surface, composed of 5 separate teeth)
Movement in Phyla Echinodermata
use podia for movement along substrate
Name the five Echinodermata Lineages
1. Crinoidea (feather stars, sea lilies)
2. Asteroidea (sea stars)
3. Ophiuroidea (brittle stars and basket stars)
4. Echinoidea (sea urchins, sand dollars)
5. Holothuroidea (sea cucumbers)
Reproduction in Phylum Echinodermata
typically reproduce sexually, have separate male and female sexes, some can also reproduce asexually (through regeneration)
Characteristics of Phylum Hemichordata
pharyngeal gill slits, marine, sessile suspension feeders [acorn worms]
Characteristics of Xenoturbella
marine-dwelling, only two species, worm-like body, lacks brain/through gut/excretory system, feeds on molluscs
What are synapomorphies of Phylum Chordata?
1. pharyngeal gill slits
2. notochord (used to support nerve cord)
3. dorsal hollow nerve cord
4. post-anal tail (muscular tail that extends past nerve cord)
What are the 3 major lineages of Phylum Chordata?
1. Urochordates (tunicates)
2. Cephalochordates (lancelets)
3. Vertebrates (most common)
Characteristics of Urochordates
tunicates [sea squirts] are marine, small suspension feeders, attach to rocks or hard substrates, have all qualities of chordates as larvae but only keep pharyngeal gill slits as adults
Characteristics of Cephalochordates
lancelets are small marine mobile suspension feeders, burrow into substrate, look fish-like
What are the most successful deuterostome lineages?
echinoderms and vertebrates (due to evolution of unique body plans)
What are the the two most species-rich lineages among vertebrates?
1. Ray-finned fishes
What are synapomorphies of Vertebrates?
posession of a skull/cranium (either bony or cartilaginous)
NOT ALL VERTEBRATES HAVE VERTEBRAE
What are the lineages without vertebrae?
Characteristics of Hagfish
lack vertebral column, lack jaws, lack paired fins, aquatic scavengers and predators, feed on carcasses of dead whales and fish (detritivores and predators)
Characteristics of Lamprey
have small pieces of cartilage along length of nerve cord that resemble vertebrae, lack jaws, lack paired fins, ectoparasites
Body structure of Class Chondrichthyes
do not have swim bladders, cartilaginous vertebrae, jaws, paired fins (ex. sharks, rays, skates)
What Class was the first to show evolution of jaws?
Class Chondrichthyes (sharks, rays, skates), Subphylum Vertebrate, Phylum Chordata - about 430mya
Where do jaws come from?
Hypothesis: selection acted on mutations that affected structure of gill arches; evidence: both gill arches consist of tissue that bends forward, both are derived from same embryonic cells, muscles that move gill arches and jaws derived from same embryonic cells
Feeding in Chondrichthyes
most are predators (evolution of Jaws), sharks are active hunters, skates are sit-and-wait predators, some rays and sharks are suspension feeders (ex: whale shark)
Movement in Chondrichthyes
sharks swim by undulating bodies and beating tails, rays and skates use enlarged pectoral fins to flap
Reproduction in Chondrichthyes
sharks have internal fertilization, eggs may be shed into water, or retained until young are hatched, some sharks and rays give live birth, other species deposit eggs in vegetation
What is most species-rich lineage in sub-phylum verbrata?
What are synapomorphies of ray-finned fishes (Actinopterygii)?
interlocking scales, ray-like fins (fins supported by long boy rods), and swim bladders
Feeding in Actinopterygii
different species have different adaptations of the mouth, jaws, and teeth that allow them to specialize on certain foods
What are some jaw modifications in Actinopterygii?
protrusible jaw, pharyngeal jaws (modified gill arches that function as a second set of jaws)
What is the difference between cichlid and non-cichlid?
Cichlid has additional pharyngeal jaw located behind oral jaws that can bite down on food, non-cichlids have a pharyngeal jaw that floats (suspended by muscle)
Movement in Actinopterygii
swim by alternately contracting muscles on either side of body, results in rapid undulations, pectoral fins provide more stability and steering
Reproduction in Actinopterygii
most use external fertilization and are oviparous, however many variations exist
What are the modes of reproduction?
1. Sexual (separate male and female sexes)
2. Hermaphroditic (an individual possesses both male and female gonads - they may ore may not be able to self-fertilize)
3. Asexual (females can reproduce eggs without being fertilized, i.e. parthenogenesis)
What are two transitional species between marine and land vertebrates?
What are synapomorphies for coelacanths?
Characteristics of Coelacanths
fins supported by linear bones and muscles, live deep in water (150-700m), eat fish, swim by waving pectoral and pelvic fins like tetrapods use limbs in walking, living fossil
Characteristics of Lungfish
fins supported by linear bones and muscles that allow for walking along bottom of pond, possess lungs that supplement oxygen taken in by gills, omnivorous, live in shallow ponds and rivers
What is the fossil evidence for a fin-to-limb transition?
bone position/location has not changed over time between lobe-like fin and limb that can support full body weight
What are synapomorphies that unite Lungfish and Tetrapods?
tooth enamel, four specialized limbs, lungs
Characteristics of Amphibians
terrestrial adults but aquatic as eggs/larvae; gas exchange occurs across moist mucus covered skin, but most species also have lungs [frogs, salamanders, caecilians]
Feeding in Amphibians
have long extensible tongue that attaches at front of mouth, all adults are carnivorous and feed on land, many juveniles feed in water
Movement in Amphibians
frogs and toads jump, salamanders walk, caecilians lack limbs and burrow in soil
Reproduction in Amphibians
frogs have external fertilization, rely on water to keep eggs moist; salamanders and caecilians have internal fertilization; caecilians are viviparous
What are characteristics of an amniotic egg?
have shells that minimize water loss but allows for gas exchange, contain membrane-bound supply of nutrients in albumen
What is albumen?
water in a protein-rich solution, inside amniotic egg, provides water and mechanical support
What is Amnion?
protective inner membrane that envelops the embryo
What is the yolk sac?
membranous pouch that contains nutrients for the growing embryo
What is the allantois?
membranous pouch that holds waste materials in an amniotic egg
What is the chorion?
structure that allows gas exchange between embryo and surrounding air in amniotic egg
What are synapomorphies of Class Mammalia?
possess hair or fur, possess mammary glands and lactate (make milk for young)
What is a characteristic of Class Mammalia that is NOT a synapomorphy?
endothermic (temperature maintained independent of environment)
What is most ancient lineage of all Mammalia?
Monotremes (platypusses and echidnas)
Characteristics of Monotremes
only three species exist, lay eggs, possess fur, lactate
Characteristics of Marsupials
give birth to under-developed young after a short embryonic period, young continue to develop while attached to their mother's nipple
What are evolutionary reasons for development of placenta?
portability, protection, primo temperature (more constant and favorable)
What is a placenta?
sac in mother that is rich in blood vessels, facilitates the flow of oxygen and nutrients from mother to offspring (embryo emerges after longer period of gestation)
Feeding in Eutheria (Placental Mammals)
size and structure of teeth correspond closely to diet, many modifications in feeding apparatus
Reproduction in Eutheria
fertilization and development is internal, viviparous, prolonged period of parental care is common
Characteristics of Reptiles
amniotic, all reptiles are ectothermic (except birds)
Characteristics of Class Testudinia
distinguished by a shell composed of bony plates that fuse to the vertebrae and ribs, lack teeth but jawbone and lower skull form a bony beak (ex. turtles and tortoises)
Characteristics of Class Lepidosauria
most lizards have well-developed jointed legs, snakes are limbless but have remnants of limbs (suggests they secondarily lost legs)
Characteristics of Class Crocodilia
placement of eyes and nostrils allows them to sit underwater for extended periods, predatorial (teeth are continually replaced), oviparous reproduction with parental care
What is unique about Pterosaurs?
"winged lizard," lived 228-65 mya, first vertebrates to evolve flight
What are synapomorphies of Class Aves?
all birds have feathers
Characteristics of Dinosaurs
dominant vertebrates for 160 million years, fossils from Triassic to Cretaceous (often misused to include paraphyletic lineages like Ichthyosaurs, which were actually lizards)
Characteristics of Class Aves
a type of dinosaur, descended from ancestor that had feathers, most bird species can fly, endothermic
For Chordates, do phylogenetic trees based on morphological features agree with phylogenetic trees based on molecular data?
YES, but this is not the case for protostomes (morphological phylogenies conflict with molecular phylogenies)
What suggests that a sea-slug is a plant-animal hybrid?
eats algae and then can make its own food, stores algae chloroplasts in its gut, can steal this gene from algal food that can then be passed on to offspring and the offspring do not have to eat
What are the two main lineages of Primates?
Characteristics of Prosimians
most live in trees and are active at night, "before-monkeys," (lemurs, tarsiers, pottos, and lorises)
Characteristics of Anthropoids
include New World monkeys (found in Central and South America) and Old World monkeys (found in Africa and Asia), and great apes (orangutans, gorillas, chimps, humans)
Distinguishing characteristics of primates
eyes on front of face, tend to have hands and feet that are efficient at grasping, flattened nails instead of claws, brains that are large relative to body size, color vision, complex social behavior, extensive parental care of offspring
What is lineage of the great apes?
What are synapomorphies of Hominins?
bipedalism defines hominins (monophyletic group that includes Homo sapiens and over a dozen extinct, bipedal relatives)
What are four major groups of fossil hominin species?
1. Gracile Australopithecines (slender, bipedal, 4.12-2.4 mya)
2. Robust Australopithecines (bipedal, 2.7-1.0 mya, massive teeth and jaws)
3. Early Homo (humans, larger braincases, flatter and narrower faces, potential tool-making)
4. Recent Homo (1.2mya - present, includes Cro-Magnons and Neanderthals)
What can be concluded from the hominin fossil record?
1. shared characteristic is bipedalism
2. several species of hominin lineage were present simultaneously during evolution
3. fossils from more than one species found in same geographic location and age (hominin species lived in physical contact)
4. compared with earlier hominins, genus Homo have extremely large brains relative to overall body size (introduction of speech)
What is the Out-of-Africa Hypothesis?
modern humans originated in Africa and that population that left Africa split into a group that colonized Europe and Russia and a group that eventually spread throughout rest of world [contends that Homo sapiens, Neanderthals, H. erectus, and H. floriensis never interbred]