Biology Notes (ETC) 04/03/24

Ch. 29

• How old they are = 1.5 million years

• Animal = multicellular, muscle & nerve cells, digest food internally

3 muscle types

• Skeletal: striated & voluntary

• Smooth: involuntary, hollow organs

• Cardiac: Heart

Unique junctions

• Tight Junction= prevents fluid exchange

• Gap junction= fluid exchange

• Desmosomes= have filaments surrounding the cell

Embryo

- zygote (undergoes cleavage) → during cleavage → blastula (hollow ball) THEN rearranges to → gastrula

- Endo= give RISE → digestive tract

- Ecto= give RISE → skin & muscles

- Meso= give RISE → muscle, reproductive

• Proterosterm= mouth → anus

• Deuterosterm= anus → mouth

Animal Body Plan’s

Symmetry

• Asymmetric

  • Condition in which the body lacks a plane through which body can be divided into mirror images

    • not symmetric (sponge)

• Radial

  • Condition in which any two halves of a body are mirror images of each other, providing the cut passes through the center

    • pizza like

• Spherical

  • Condition in which a cut in any plane through the center yields equal halves

    • No animal (volvox)

• Bilateral

  • Condition in which only the right and left sides of an organism, divided by a single plane through the midline, are mirror images of each other

    • Humans

Body cavities

1. Acoelomates= no body cavity (flat worms)

2. Coelomates= digestive cavity is suspended

3. Pseudocoelomates= digestive cavity is not suspended (earthworm)

- Body Segmentation

-Appendages

Cephalization

• Anther=head

• Anterior = front end

• Posterior = back end

• Ventral = bottom side

• Dorsal = top sides

Non-Bilaterians

• Either asymmetrical OR radially symmetrical

• No nervous system OR simple nerve nets

• Monoblastic OR diploblastic

Phylum: Ctenophora → comb jellies

• Diploblastic

• Symmetry: Radial

• Complete gut

• Lack muscular tissue

  • 8 rows of cilia called → ctenes

• Sexual reproduction

  • Happens outside the body

    • Using gametes ejected out the mouth/anus

Phylum: Porifera → sponges

• LACK true tissues

• Sequential hermaphrodites

Eumetazoans

• Possess some form of body symmetry

• A gut

• Nervous system

• Tissues organized into distinct organs

Phylum: Cnidaria → hydras (Hydrazoa) , corals (Anthozoans) , & jellies (Scyphozoa)

• Diploblastic

• Symmetry: Radial

• 2 growth forms

  • Medusa: free swimming with opening to digestive tract oriented downward

  • Polyp: Is sessile, cylindrical forms that adhere to a substrate; digestive opening oriented upward

Ch. 30 Protostomes

• Type of symmetry of all Protostomes: Bilateral

• Contain: Lophotrochozoans & Ecdysozoans

Phylum: Platyhelminthes

• Mostly parasitic

• NO DIGESTIVE SYSTEM = they diffuse their nutrients through their skin

• Dorsally flattened

• Classes:

- Turbellaria (Flatworms); non parasitic

- Trematoda (Blood Flukes); number 1 disease Schistosomiasis BELOW malaria

- Cestoda (Tapeworms); scolex allows them to hook into the digestive walls; have hooks and suckers

Phylum: Rotifera

• They have a digestive tract

• Pseudocoelomates

• Corona: cilia create water current for feeding

• Some are parthenogenic: population exists entirely of female that produce more females from unfertilized eggs

Phylum: Annelida

• Classes:

- Polychaeta (Clam worms)

- Clitellata; Movement is bad because they have less chia

two sub clades- Oligochaetes (earthworms; biogrowth & hermaphrodites) & Hirudinea; leeches (parasites)

Phylum: Mollusca

• 4 Classes:

- Polyplacophora (Chiton); Open circulatory system

- Gastropoda (Snails & slugs); torsion: eternal organs are above their head in their shell; Open circulatory system

- Bivalvia (Clam) have no external head; no radula; Open circulatory system

- Cephalopoda (Octopus, Squids, & Nautiluses); Closed circulatory system; Smartest of the bunch (complex brain)

Mollusks Anatomy

• Radulla (Sandpaper tongue)

• Mantle: (Part of the body that makes the shell= made up of CaCO3)

• Visceral mass: Contains vital organs

• Foot: Used for movement

• Coelomates: All HAVE digestive tracts

Ch. 31 Deuterostomes Animals

• Blastopore → Anus

• Colem from mesoderm

• Chormate, echinodermata

Echinoderms & chordates

• All posses deuterostomic pathway for embryonic development

2 major groups:

• Phylum Echinodermata

• Phylum Chordata

Phylum: Echinodermata

(sea stars, urchins, sea daisies)

• Echinoderms are mainly slow moving or sessile marine animals

• Bilateral symmetry (special case called: pentaradial symmetry)

• No anterior/posterior or dorsal/ventral (oral/aboral instead)

• Larvae are bilaterally symmetrical

- 5 Classes:

- Asteroidea (sea stars & sea daisies [armless] ); tube feet on ventral side; feed on bivalves; can regenerate appendages “think patrick star”

- Ophiuroidea (brittle stars {distinct central disk & long/thin arms} ); lack flattened surface of tube feet; move by thrashing arms; suspension feeders others predators or scavengers

- Echinoida (sea urchins [spherical] & sand dollars [flattened] {no arms} ); move by five rows of tube feet; mouth on ventral surface

- Crinoidea (sea lilies [sessile] & feather stars [crawl around w/flexible arms] ); suspension feeders; arms surround dorsal mouth “think japanese fan”

- Holothuroidea (sea cucumbers); lack spiny skin; elongate rather than flattened dorsoventrally; 5 rows of tube feet; ejects parts of gut out anus; regrows lost intestine “think kevin the sea cumber”

Phylum: Chordata

2 groups of invertebrates & the vertebrates:

• Subphylum: Cephalochordata (invertebrates)

• Subphylum: Urochordata (invertebrates)

• Subphylum: Vertebrata (vertebrates)

Chordates: All share 4 derived characteristics

• Notochord (longitudinal, flexible rod between digestive tube and nerve cord), made of: large fluid filled cells surrounded by stiff fibrous tissue, provides: -skeletal support for length - firm structure against which muscles can work vertebrates= jointed skeleton develops around notochord

• Dorsal, hollow nerve cord (develops from ectoderm & rolls into tube dorsal to notochord), gives rise to central nervous system

• Pharyngeal gill slits or clefts (pouches that develop from pharynx posterior to mouth), allow water flow into mouth, aid in suspension feeding & aquatic respiration, tetrapods do not become slits

• Muscular post- anal tail (aid in movement)

Subphylum: Cephalochordata [lancelets]

• Larvae possess all 4 chordate characteristics

• Respiration across its body

Subphylum: Urochordata [tunicates]

• Larval stage exhibits chordate characteristics BUT adult stage does not

• Notochord, tail, & nervous system resorbed

Subphylum: Vertebrata [Skull & backbone]

• Anterior skull of cartilage or bone encasing brain

• Internal organs suspended in a true coelom

• 2 chambered heart, hemoglobin, & kidneys

Class Myxini- Hagfishes

• Skull of cartilage, lack jaws & vertebrae

• Weak circulatory system w/ 3 small accessory hearts

• Generate “slime” to fend off scavengers

Class Petromyzontida- lampreys

• Most parasites

• Skeleton is cartilage

Gnathostomes [ Jawed vertebrates ]

• 3 large groups: Chondrichthyans, Ray-finned fishes, & lobe fins

Class Chondrichthyans- Sharks, rays, & relatives

• Biggest, most diverse, & most successful predators in oceans

• Skeleton cartilaginous with some calcium hardening portions

• Constantly swim to keep flow of water over gills & not sink

• Most carnivorous but largest suspension feeders

• Lack ears; vibrations through body sent to inner ear

Clade Osteichthyes: Ray-finned fishes & Lobe-fins

• Ossified (bony) endoskeleton hardened with calcium phosphate

• Breathe via gills & have a bony operculum covering gills

• Control buoyancy with swim bladder

• Covered in scales & mucus

• Lateral line system

Class Actinopterygii- Ray-finned Fishes

• Most commonly known fishes

• Flattened scales cover body

• “Single Circulation” - heart pumps blood to gills then continues onto body for oxygen drop off before returning to heart

Class Sarcopterygii- Lobe-fins

• Ancestor

• Thought to be extinct

• Evolution to tetrapods

• True lungs

Tetrapods [Gnathostomes with limbs]

• 4 appendages

• Lobed finned fishes

  • Arrived 365 million yrs ago

• Neck = lack gills

Class Amphibia- Salamanders, frogs, and caecelians

• Order Urodela- Salamanders; aquatic or land; adult form still have characteristics of the larva

• Order Anura- Frogs & toads; land hopping; rely on water; skin toxins

• Order Apoda- Caecilians; legless & nearly blind

Amniotes: Tetrapods with terrestrially adapted eggs

• Members include: Reptiles (Including birds), & mammals

• Amniote Egg: Contains 4 membranes; amnion, chorion, yolk sac, and allantois

• Rib cage used to ventilate larger lungs

Reptiles

Class Reptilia- Tuataras, lizards, snakes, turtles, crocodilians, & birds

• Cold blooded

• Lay eggs on land

• Aminon, chiron, yolk, allantosis

• Gas exchanges, waste storage, water proofing, nutrient storage

• Not all amote eggs are classified

• 2 lineages diverged from diapsids (holes in the jaw) :

• Lepidosaurs: Tuataras, lizards, snakes (vary in size)

• 3 chambered heart partially separates oxygenated & deoxygenated blood

• Archosaurs: Crocodilians, pterosaurs, & dinosaurs (including birds)

• Crocodilians: Alligators & Crocodiles

• Beginning late Triassic

• Provide parental care to offspring

• 4 chambered heart- complete double circulation; can cut off circulation in certain parts of the heart

• Birds

• Weight-reducing adaptations; no bladder, one ovary, lack teeth, reduced/lost & fused bones

• Air sacs

• ENDOTHERMS

• Feathers & wings

  • Keeled sternum

• 4 chambered heart

• Extremely acute vision, hearing, fine motor control, & brain function

2 groups: Paleognaths & Neognaths

Origins

• Evolved from → Archaeopteryx (teeth & claws on wings)

Mammals

Unique traits:

• Mammary glands: modified apocrine glands that create milk to feed offspring

• Hair & subcutaneous fat insulation

• Sweat glands: evaporative cooling process

• ENDOTHERMIC; 4 chambered heart

• Large brain, learning, play

• Differentiated teeth

• 3 middle ear ossicles

Extant mammals:

• Monotremes: egg laying mammals

• Marsupials: pouched mammals with short gestation where development completes in pouch

• Eutherians: mammals with long gestation where development occurs in uterus

Primates

• Hands for grasping

• Flattened faces, nails

• Depth perception

• Opposable thumb

2 major group of primates:

1. “Wet-nosed” primates- Strepsirrhines

• Lemurs, lorises, & galagos

  • Arboreal & nocturnal

1. Dry- Nosed primates- Haplorhines

• Tarsiers, New World Monkeys, Old World Monkeys, & Apes

Large primates

• Highly social

• Long arms

• Short tail

Homosapiens

• Small jaw bones

• Upright & bipedal

• Play

• Ancestor: Hominid

Ch. 38 Physiology, Homeostasis, & Temp. regulation

Multicellular

Allows organisms to get big

• Advantages:

  • Prey on others, strength to resist environmental forces

• Disadvantages:

  • More need for nutrients, tough to move nutrients

Allows for specialization

• Advantages:

  • Increased efficiency of certain functions

• Disadvantages:

  • Loss of other functions, need for coordination

Body Plans to Maximize SA: V

• Sac-like body

  • Both outer & inner layer of cells can exchange materials with water

• Flat body

  • Expososes a maximum number of cells to environment & minimizes cells not exposed to environment

• Extreme branching OR folding

  • Large species can increase the ration by increasing surface area of individual tissues

    • Lungs, GI tract, circulatory system, kidneys

System of Coordination

2 systems responsible for coordination

1. Endocrine system

• Signaling molecules released → bloodstream; transmitted to whole body

• Creates hormones

• Slowly acting BUT long lasting

1. Nervous system

• Cells transmit nerve impulses between two specific locations

  • Autonomic nervous system → “life support” functions

  • Parasympathetic → “Rest & digest”

  • Sympathetic → “Fight, Flight, or Freeze”

• Fast acting BUT short lasting

Feedback Control

Organisms can be regulators OR conformers

• Regulators

  • Control their internal environment with internal mechanisms

• Conformers

  • Allow their internal environment to change in accordance with external environment

• Homeostasis

  • Process of maintaining a relatively stable internal environment → external environment varies

Physiological Control

• Negative Feedback

  • Mechanism of regulation where a change in the controlled variable triggers a response to counteract the initial change

• Positive Feedback

  • Mechanism of regulation where a change in the controlled variable triggers a response to enhance the initial change

Thermoregulation

Process by which an animal maintains an internal temperature within a tolerable range

• Endotherms

  • Heat source is metabolic (internal)

    • Birds & mammals

• Ectotherms

  • Heat source is (external) environment

    • Amphibians, lizards, snakes, turtles, fishes, and most invertebrates

Body temp.

• Homeotherm

  • Body temperature remains relatively constant

    • Normally endotherms

• Poikilotherm

  • Body temperature varies with its environment

    • Normally ectotherms

• Heterotherms

  • Modify behavior/metabolism depending on need

    • Some animals that don’t fit in top two categories (marmots)

Temp Control.

4 methods of controlling body temp.

• Conduction

  • Direct transfer of heat when objects of different temps come into contact

• Convection

  • Heat is lost when a stream of air is cooler than body surface temp

• Radiation

  • Warmer objects lose heat to cooler objects

• Evaporation

  • Of water from body surfaces OR breathing passages cools the body

Blood Flow

• Vasoconstriction

  • Skin vessels small to conserve heat

• Vasodilation

  • Skin vessels large to release heat