BIO 201 Exam 4

Invertebrates

animals that lack a backbone

1. make up 95% of species on Earth

Sponges

The informal name for animals in the phylum Porifera

1. sedentary and live in marine environments

2. lack true tissues and organs

3. filter feed, meaning they capture food particles that filter through their bodies

Cnidarians

A phylum of aquatic animals that are a wide range of sessile and motile forms including jellies, corals, and hydras

1. relatively simple diploblastic body plan

2. gastrovascular cavity is the central digestive compartment

Two variations of body plans

1. Sessile Polyp

2. Motile Medusa

Polyp

adheres to the substrate by the aboral end of its body

Medusa

has a bell-shaped body with its mouth on the underside and move freely

Flatworms

undergo triploblastic development but are coelomates

1. gastrovascular cavity with one opening

Planarians

best known flatworms that live in the water and prey on small aquatic animals

1. have light sensitive eyespots and centralized nerve sets

2. they are hermaphrodites can reproduce asexually through fission or sexually

Parasitic Species

1. Trematodes

2. Tapeworms

Trematodes

parasitize a wide range of hosts and have a complex life cycle with alternating sexual and asexual life cycles

1. They produce proteins that mimic their host and release molecules that manipulate their host’s immune system

Tapeworms

Parasites of vertebrates that lack a digestive system

1. tapeworms absorb nutrients from the host’s intestine

Molluscs

includes snail and slugs, oysters and clams, octopus and squids

1. soft bodied animals but some are protected by a hard shell

Molluscs similar body plan

1. Muscular foot

2. visceral mass

3. mantle

Four major classes of molluscs

1. polyplacophora - chitrons

2. gastropoda - snails and slugs

3. bivalvia - clams and oysters and other bivalves

4. Cephalopoda - squids, octopuses, cuttlefish, and chambered nautiluses

Bivalves

aquatic and include many species of clams, oysters, mussels, and scallops

1. they have a shell divided into 2 halves drawn together by abductor mussels

2. mantle cavity of a bivalve contains gills that are used for feeding and gas exchange

Cephalopods

Carnivores with beak-like jaws surrounded by tentacles of their modified foot

1. Octopuses creep along the ocean floor searching for prey

2. squid siphon a jet steam of ink

3. nautiluses are the only group of shelled cephalopods

Annelids

coelomates with bodies composed of a series of a fused rings

3 Clades of annelids

1. Polychaeta

2. Oligochaeta

3. Hirundinea

Leeches

include predators of invertebrates and parasites that suck blood

1. secrete a chemical called hirudin to prevent blood from coagulating

Earthworms

Hermaphrodites but cross fertilization

1. they eat through soil, extracting nutrients as the soil moves through the alimentary canal

Ecdysozoans

the most species rich group of animals covered by a tough coat called a cuticle

1. the cuticle is shed through a process called ecdysis

Nematodes

also called roundworms, are found in aquatic habitats, soil, most tissues of plants, and in body fluids and tissues of animals

Arthopods

make up rthoAtwo out of every three species of animals

1. have eyes, olfactory receptors and antennae that function in touch and smell

Arthopod body plan

1. segmented body

2. tough exoskeleton,

3. jointed appendages

Open circulatory system

hemoglyph is circulated into the spaces surrounding tissues and organs Ara

Arachnids

include spiders, scorpions, ticks and mites

1. have six pairs of appendages: the chelicerae, the pedipalps, and four pairs of walking legs

2. produce silk from specialized abdominal glands

Myriapods

includes millipedes and centipedes, that have a pair of antennae and three pairs of appendages modified as mouthparts crustaceans C

Crustaceans

have highly specialized appendages

1. smaller crustaceans have gas exchange, larger ones have gills

2. Isopods include terrestrial, freshwater and marine species

3. Decapods are all relatively large crustaceans that include lobsters, crabs, crayfish, and shrimp

Insects

Their internal anatomy is comprised of many complex organ systems

1. diversified many times through the evolution of flight

Deuterostomes

1. Echinoderms

2. Chordates

Deuterostomes share developmental characteristics

1. Radial cleavage

2. formation of the anus from the blastopore

Echinoderms

sessile or slow moving animals like sea stars

1. have a unique water vascular system of hydraulic canals that branch out into tube feet

Vertebrates

Chordates that get their name from the series of bones that run up their backbone

1. colonized the earth 365 MYA

Chordates

bilateran animals that belong to the clade of animals known as Deuterostomia

1. comprise all groups of vertebrates and two groups of invertebrates

Derived Characteristics of Chordates

1. Notochord

2. Dorsal, hollow nerve cord

3. Pharyngeal slits or clefts

4. muscular or post anal tail otoN

Notochord

a longitudinal, flexible rod between the digestive tube and nerve tube that provides sketal support

1. In most vertebrates the skeleton develops and the adult only retains remnants of a notochord

Dorsal, Hollow Nerve Cord

develops into the central nervous system the brain and the spinal cord

Pharyngeal clefts

grooves in the pharynx that develop into slits that open to the outside of the body

Fuunctions of pharyngeal slits

1. Suspension-feeding structures in many invertebrate chordates

2. gas exchange in vertebrates (except tetrapods)

3. develop into parts of the ear, head, and neck

Lancelets

named for their bladelike shape, they are marine suspension feeders that retain characteristics of the chordate body plan as adults

Tunicates

are mostly closely related to other chordates than lancelets, only resemble lancelets in their larval stage

Vertebrates are chordates with a backbone

The skeletal system of complex nervous system have allowed vertebrates efficiency at two essential tasks

1. Capturing food

2. Evading predators

Derived Characteristics of Vertebrates

1. Neural crest

2. vertebrae enclosing a spinal cord

3. an elaborate skull

4. Fin rays, in the aquatic forms

Hagfishes and Lampreys

The two remaining lineages of jawless vertebrates

1. these groups lack a backbone

2. presence of rudimentary vertebrates and the results of phylogenetic analysis led to the conclusion that they are vertebrates

Gnathastomes

Vertebrates that have jaws

1. include sharks, ray-finned fishes, lobe-finned fishes, amphibians, reptiles, and mammals

2. named for their hinged jaw that use teeth to grip food items firmly and slice them

3. jaws were hypothesized to have evolved from skeletal rods oC

Common characteristics of gnathastomes

1. genome duplication including more hox genes

2. enlarged forebrain associated with enhanced smell and vision

3. In aquatic gnathastomes, the lateral line system is sensitive to movement, vibrations, and pressure

Chondrichthyans

have a skeleton composed primarily out of cartilage

1. includes sharks and rays

Sharks

have streamlined body and are swift swimmers; the largest are suspension swimmers, but most are carnivores

1. short digestive tract with a ridge called that spiral valve to increase the digestive surface area

2. Sharks have acute senses and a unique sense of smell

3. shark eggs have fertilized internally but embryos can develop in different ways

Oviparous

eggs hatch outside of mothers body

ovoviviparous

embryo develops within the uterus and is nourished by the egg yolk

viviparous

the embryo develops within the uterus and is nourished through a yolk sac placenta from the mother’s blood

Cloaca

the common reproduction tract that the digestive tract empties into

osteichthyans

have a bony endoskeleton and include the bony fishes and tetrapods

1. most vertebrates belong to this clade

Ray-finned fishes

include nearly all the familiar aquatic osteichthyans

1. fins are mainly supported by long, flexible rays that are modified for maneuvering, defense, and other functions

Lobe Fins

originated in the Silurian period and have muscular pelvic and pectoral fins that they use to swim and walk underwater across the substrate

Derived characters of Tetrapods

1. four limbs, feet with digits

2. a neck, which allows for separate movements of the head

3. fusion of the pelvic girdle to the backbone

4. absence of gills

5. ears for detecting airborne sounds

Amphibians have three clades

1. Urodela (salamanders)

2. Anura (frogs)

3. Apoda (caecilians)

Salamanders

Amphibians with tails that often have Paedomorphosis, when juvenile features are retained into adulthood

Frogs

lack tails and have powerful legs for locomotion on land

Caecilians

legless, nearly blind, and resemble earthworms Am

Amniotes

a group of tetrapods whose living members are the reptiles, including birds and mammals

Reptiles

this clade includes he tuataras, lizards, snakes, turtles, crocodilians, birds, and some

extinct groups

1. lay shelled eggs on land

2. have scales that create a waterproof barrier

Crocodilians

belong to an archosaur lineage

1. pterosaurs were the first tetrapods to exhibit flight

Theropods

descended from pterosaurs and from which birds descended

Lepidosaurus

surviving lineage of these is represented by 2 species of lizard-like reptiles called tuataras

1. restricted to living off the coast of New Zealand

2. snakes an legless lepidosaurus that evolved from lizards

Birds

Archosaurs but almost every feature of their reptilian anatomy has undergone modification for flight

Derived Characters of Birds

1. adaptations that facilitate flight

2. wings with keratin feathers

3. lack of urinary bladder, females, with only one ovary, small gonads, and loss of teeth

Mammals

are only around 6,000 species but have dominated in most environments

Derived Traits of Mammals

1. mammary glands —> produce milk

2. high metabolic rate

3. hair

4. later brain of other vertebrates of equivalent size

5. differentiated teeth

Monotremes

are a small group of egg-laying mammals consisting of echidnas and the platypus

Primitive Monotreme Features

1. Cloaca

2. Egg-laying

3. Primitive skeletal features (closer to reptiles)

4. Egg-tooth

Marsupials

include koalas, opossums, and kangaroos

1. embryo develops