Bio 2 Animal Phylogenies & Characteristics

4 Characteristics of Animals

1. Multicellularity

2. Heterotrophic Metabolism

3. Internal Digestion

4. Movement and Nervous Systems

Diploblastic animals have _____ cell layers: the ______ and ________.

two; ectoderm; endoderm

Triploblastic animals have ________ cell layers, the ___________ , ____________, and ___________.

three; ectoderm; endoderm; mesoderm

Protostomes

Blastopore develops into the mouth; anus forms later

Body Plan

General structure, arrangement of organ systems, and integrated functioning of body parts

Three types of symmetry:

1. asymmetry

2. radial symmetry

3. bilateral symmetry

Radial Symmetry

Body parts arranged around a central axis

Bilateral Symmetry

Body can be divided into mirror image halves on only one plane

Body Cavity Structure: Acoelomate

No fluid-filled body cavity

Body Cavity Structure: Pseudocoelomate

Body cavity is pseudocoel, a fluid-filled space in which internal organs are suspended; no mesoderm around internal organs

Body Cavity Structure: Coelomate

Body cavity is a coelom that develops within the mesoderm; lined with a layer of muscular tissue, called the peritoneum

Hydrostatic Skeletons

• some body cavities

• when muscles contract, fluid is pushed to another part of the cavity, which causes that region to expand

Acoelomate: Flatworm

• ectoderm, mesoderm, mesenchyme, gut (endoderm)

• does not have enclosed body cavity

• space between gut and body wall filled with mesenchyme

• move by beating cilia

Pseudocoelomates: Roundworm

• ectoderm, mesoderm, pseudocoel (cavity), gut (endoderm)

• pseudocoel is lined with mesoderm

• no mesoderm surrounds internal organs

Coelomates: Earthworms

• ectoderm, muscle (mesoderm), internal organs, peritoneum (mesoderm), coelom (cavity), gut (endoderm)

• coelom and internal organs surrounded by mesoderm

Role of Segmentation

Facilitates specialization of body regions; animal can alter body shape and control movements precisely

Role of Appendages

Enhance an animal’s ability to move around

True or False: Appendages include antennae, claws, mouthparts, and reproductive organs

True

Nerve Nets

Found in ctenophores and cnidarians; diffuse nervous systems

Bilaterian Nervous Systems

• well-coordinated

• muscle action is coordinated allowing movement of appendages and body parts

• sensory information is gathered and processed

First two lineages to split from remaining animals:

sponges and ctenophores

Sponges

• 9000 species

• skeleton made out of silica

• spicules (resemble hooks) are carnivorous

Ctenophores

• comb jellies

• radial symmetry

• diploblastic

• move by beating cilia arranged on eight comb-like plates called ctenes

Placozoans

• “the blobs”

• asymmetrical

• diploblastic

• 4 cell types

• no mouth, no gut, or nervous system

Cnidarians

• jellyfish, sea anemones, corals, hydrozoans

• gastrovascular cavity

• nematocysts

Functions of gastrovascular cavity in cnidarians:

• digestion

• circulation

• gas exchange

• hydrostatic skeleton

Nematocysts in cnidarians

Specialized harpoon-like structures with toxins used to catch large prey

Protostomes have an ________ ________ and a ventral ___________ _____________ .

anterior brain; nervous system

2 Protostome Clades:

1. lophotrochozoans

2. ecdysozoans

Protostome ancestor has a _________ . This has been lost in _________ and modified in _________ .

coelom; flatworms; mollusks

Lophotrochozoan: Annelids

• coelom in each segment isolated from others

• lack rigid protective covering

• permeable body wall

Lophotrochozoan: Mollusks

• mantle covers internal organs of visceral mass

• muscular foot used for locomotion

• modified arms and tentacles in cephalopods

Ecdysozoans grow by shedding ________ .

cuticle

Ecdysozoans: Nematodes

• unsegmented

• roundworms

• shed cuticle 4 times

Ecdysozoans: Arthropods & Relatives have _______ appendages

paired

Ecdysozoans: Chelicerates

• head has 2 pairs of appendages modified into mouthparts

• sea spiders - most small

• horseshoe crabs

• arachnids

Ecdysozoans: Arachnids

• spiders, scorpions, harvestmen, mites, ticks

• some mites and ticks are parasites

• spiders are terrestrial predators

Ecdysozoans: Mandibulates

• mouthparts are mandibles, used for chewing, biting, holding prey

• myriapods: segmented trunks with many pairs of legs

• centipedes: one pair of legs per segment

• millipedes: two pairs of legs per segment

Ecdysozoans: Crustaceans

• shrimps, lobsters, crayfish, crabs, isopods, barnacles, ect

• appendages are specialized

• 3 body regions: head, thorax, abdomen

Ecdysozoans: Hexapods

• insects and their relatives

• wingless or with wings

• body plan: head, thorax, abdomen

• three pairs of legs to thorax

• most groups have thorax with two pairs of wings

• gas exchange system of air sacs and channels

• external openings called spiracles

Metamorphosis

Substantial morphological changes between developmental stages

Incomplete Metamorphosis

changes are gradual

Complete Metamorphosis

changes are dramatic

_______ were the first flying animals

Pterygote

Deuterostomes

Blastopore develops into the anus; mouth develops later

3 Characteristics of Common Ancestor of Deuterostomia

1. bilateral symmetry

2. segmented

3. pharyngeal slits

3 Clades of Deuterostomes:

1. Echinoderms

2. Hemichordates

3. Chordates

Echinoderms

• sea stars, sea urchins, sea cucumbers, crinoids

• system of calcified internal plates fuse to form internal skeleton

• water vascular system

• tube feet - gas exchange, locomotion, feeding

Hemichordates

• acorn worms and pterobranchs

• wormlike

• marine

• 3 body parts: proboscis, collar, trunk

3 Chordate derived structures:

1. dorsal hollow nerve cord

2. tail that extends beyond anus

3. dorsal supporting rod - notochord

3 Chordate Clades:

1. Lancelets

2. Tunicates

3. Vertebrates

Chordate: Tunicates

• notochord lost during metamorphosis

True or False: Lancelets retain all chordate derived traits during entire life.

True

Key Traits of Vertebrates:

• dorsal vertebral column

• anterior skull with brain

• well-developed circulatory system

• specialized structures for locomotion and feeding

_______ were developed after Hagfish

vertebrae

_________, _________, _________ were developed after lampreys

jaws, teeth, paired fins

_________ and ________ developed after chondricthyans

bony skeleton, swim bladder

_________ were developed after ray-finned fish

lobe limbs

__________ were developed after coelacanths

internal nares

________ and _________- were developed after lungfish

terrestrial limbs, digits

Amniotes have a ________ egg.

amniote

Vertebrates: Chondrichthyans

• sharks, skates, rays, and chimaeras

• fins lack supportive rays

• skeleton made of pliable cartilage

• skin flexible and leathery

Vertebrates: Ray-Finned Fish

• swim bladders

• bones

Vertebrates: Lobe-Limbed

• coelacanths, lungfish, tetrapods

• jointed appendages

• paired fins or limbs

• paired pelvic and pectoral fins

Coelocanths have a skeleton made of ________ not bone (these are a lobe-limed vertebrate)

cartilage

Vertebrates: Tetrapods

• four legs

• early split led to amphibians and amniotes

3 Taxonomic Orders of Amphibians

1. Caecilians

2. Frogs and Toads (anurans)

3. Salamanders

Reptile Clades

1. Lepidosaurs

2. Turtles

Lepidosaurs (Reptiles)

• squamates: lizards, snakes, and amphisbaenians

• tuataras: resemble lizards; only two species survive

4 Archosaurs:

1. Crocodilians

2. Pterosaurs (extinct)

3. Dinosaurs

4. Aves (birds)

Birds are a specialized group of ___________ .

therapods

Predatory Dinos had characteristics of birds:

• bipedal

• hollow bones

• furcula (wishbone)

• 3-fingered feet and hands

• pelvis that points backwards

• may have been homeothermic

Key Traits of Mammals

• sweat glands

• mammary glands

• hair

• four-chambered heart

Energy

Capacity to create and/or maintain organization

______ energy is unable to do work, but ________ energy is.

heat; chemical

Nutrition

Study of how animals meet needs for chemical substances and energy

Calorie

The amount of heat needed to raise one gram of water by one degree celsius

Metabolic Rate

Amount of chemical bond energy consumed and converted to heat per day

Regulation

Maintaining constant internal environment

Conformers

Internal environments change according to external environment

Homeostasis

Keeping internal environment stable and the mechanisms by which this is done

Homeotherms

Maintain constant internal body temps; endotherms

Poikilotherms

Body temps are variable and determined by external temp (echotherms)

Homeotherm Mechanisms to Increase Metabolic Rate

1. Shivering: Skeletal muscles contract

2. Non-Shivering Thermogenesis: Brown Adipose Tissue with uncoupling of oxidative phosphorylation

In hot environments, homeotherms increase heat loss by ________ and ___________ .

sweating; panting

Control System Parts (4)

1. Controlled Variable

2. Sensors

3. Effectors

4. Control Mechanism

Positive Feedback

Deviations of a controlled variable from existing level are increased or amplified.

Microhabitat/Microenvironment

Places within a habitat that potentially differ from the habitat at large.

Small bodied animals deal with stresses or extremes by _______ .

behaviors

Large bodied animals depend on _______ defenses when dealing with stresses.

physiological

Countercurrent Heat Exchange System

A biological mechanism used by some animals to maintain body temperature by minimizing heat loss. In this system, arteries carrying warm blood from the heart are located adjacent to veins carrying cooled blood from extremities back to the heart. This arrangement allows the warm blood to transfer heat to the colder blood in the veins before it returns to the body core, preventing significant heat loss to the environment.

2 Challenges of a hot desert:

1. Lack of water

2. High temperatures

Small Mammals in Hot Desert:

• nocturnal

• create burrows

• avoid stresses

Large Mammals in Desert:

• Countercurrent system to keep brain cooler

• physiological defenses

Hibernation

State of low body temperature and thermal conforming that persists for a long period of time in the winter; state of thermal conformity

Metabolic Depression

Biochemically induced reduction of metabolic rate