C2.7 - Kingdom Animalia

Overview

• zoology: study of animals
• Multicellular, no walls, all heterotrophs
• Able to:
  • ingest food
  • circulate oxygen throughout body
  • dispose of undigested food and metabolic wastes
• Each species has…
  • bauplan / body plan: animal blueprint or master plan
  • incl. structural details and features like
    • type of symmetry
    • presence of body cavity
    • embryological devel.
    • segmentation
    • presence of head
    • # of limbs
    • mobility
    • presence of backbone
• >1 mil. animals in 35 phyla
• Levels of Organization (4 Types of Tissues)

What are Animals?

• Animals are eukaryotic
• Animal cells lack cell walls
• Animals are multicellular
• Animals are heterotrophs that ingest food
• Animals are motile at some point in their life cycle
• Animals form a blastula during embryological development
• blastula: hollow ball of cells

Major Groups of Animals

• invertebrates: animals w/ no backbone (i.e. earthworm)
• vertebrates: animals that have notochord and backbone at some point in life cycle
• notochord: skeletal rod of connective tissue running beneath spinal nerve chord

Body or Germ Layers

• body or germ layers: cells in embryo that give rise to specific tissues in adult
• 3 Types — def. begins w/ gives rise to
  1. ectoderm: skin and nervous system
  2. endoderm: lining of gut
  3. mesoderm: organs, muscles
     • lacking in less developed animals

Body Cavities

• coelom: fluid-filled space between body wall and gut, derived from mesoderm
  • animals that have it: humans
• pseudocoelom: cavity that lacks true mesoderm lining of true coelom
  • animals that have it: Nematodes (roundworms)

Embryological Development

• begin life as zygote when sperm fertilize egg
• blastula forms eventually
• infolding of cells occurs at particular spot in ball
• infolding eventually pushes all the way through hollow ball forming tube that connects both ends
• tube develops into digestive tract
• blastopore: first opening in digestive tract during devel.
  • protostome: animal whose blastopore develops into a mouth
    • protos = “first”, stoma = “mouth”
  • deuterostome: animal whose blastopore develops into an anus

Symmetry

• asymmetrical: no symmetry in organism
  • i.e. sponges
• radial symmetry: organism may be divided into multiple identical sections
  • i.e. jellyfish, starfish
• bilateral symmetry: organism has mirror-image right and left sides
  • organism has a true head region; concentration of nervous tissue in head
  • well-adapted for movement (streamlined to move quickly)
  • cephalization: development of distinct head w/ sense organs
  • i.e. fish, mammals, squirrels

Segmentation and Limbs

• segment: repeating parts in animals
  • in many bilaterally symmetrical animals
  • annelid: segmented worms
    • i.e. earthworms
  • diff. sections like head, thorax, and abdomen of insects can also be specialized for specific functions
• paired limbs: external paired body part that extends from main body
  • in many animals w/ bilateral symmetry and cephalization
  • uses: movement, defence, sensory
  • examples
    • antennae
    • mouthparts
    • wings
    • gills
    • legs
    • fins
    • arms
    • certain parts of tail

Phylogenic Tree of Animals

Invertebrates

Porifera

• support: protein (spongin) or mineral-based needle-like structures
• movement: adults are sessile (anchored in place)
• nervous: none
• reproduction: asexual (budding), sexual (male and female in same individual), zygotes develop into flagellated larvae

Cnidaria

• support: fluid in gastrovascular cavity gives body shape
• movement: contraction of fibers arranged in microfilaments
• nervous: nerve net
• reproduction: asexual (budding), sexual (male and female in same individual)

Platyhelminthes

• support: true muscle tissue running along body
• movement: uses longitudinal muscles
• nervous: primitive brainlike ganglia (nerve clusters) and ventral nerve cords
• reproduction: asexual (fragmentation and regeneration), sexual (male and female in same individual)

Nematoda

• support: exoskeleton called cuticle, must be shed to grow
• movement: all muscles are longitudinal, causes thrashing movements
• nervous: central brainlike ganglion, nerve cords to front and rear
• reproduction: sexual, most have separate males and females, mostly internal fertilization

Annelida

• support: fluid-filled compartments, muscles arranged circularly and longitudinally
• movement: body segmentation enables complex movement
• nervous: two ventral nerve cords connect to segmental ganglia, cerebral ganglia in head
• reproduction: sexual (male and female in same individual)

Mollusca

• support: mantle produces shell in most, muscular foot for movement
• movement: movement by muscular foot
• nervous: nerve ring around esophagus, with attached nerve cords
• reproduction: sexual, internal fertilization (external in polychaetes), most species have both sexes

Arthropoda

• support: protein and chitin exoskeleton, muscles attached to interior knobs
• movement: jointed appendages allow complex movements
• nervous: ventral nerve cord with several ganglia, two cords fuse into larger brain ganglion
• reproduction: sexual, separate sexes, internal fertilization

Echinodermata

• support: endoskeleton of hard plates, water vascular system
• movement: water vascular system operates tube feet
• nervous: nerve ring with nerve cords along each arm
• reproduction: sexual, separate sexes, gametes released externally in water

Invertebrate Bodily Processes

Amoebocytes (Multi-purpose Cells)

• Digestion: These cells take in food, break it down, and move the nutrients around the sponge.
• Circulation: These multi-purpose cells handle the movement of substances.
• Excretion: These multi-purpose cells also deal with getting rid of waste.
• Gas Exchange: Gases move in and out at the cell level, mainly by spreading out (diffusion).

Animals with a Simple Gut (Gastrovascular Cavity)

• Digestion: Food is processed in a simple pouch with one opening that acts as both mouth and anus. Nutrients spread to the cells lining this pouch.
• Circulation: In flatworms, this simple gut is branched, helping to spread nutrients.
• Excretion: Most waste moves from cells into the surrounding water. Cells with tiny hairs (cilia) push fluid containing waste out through branched tubes.
• Gas Exchange: There are no special breathing parts. Gases move across cell membranes, helped by the movement of fluids within the simple gut.

Animals with a Body Cavity (General)

• Circulation: There’s no dedicated system for moving blood. Nutrients are carried by the fluid within the body cavity.
• Excretion: A special gland or tube connected to an opening helps maintain water balance and remove some waste.
• Gas Exchange: Gases move across cell membranes.

Animals with a Complete Gut (Tube with Mouth and Anus)

• Digestion: Food goes through a full tube with a mouth at one end and an anus at the other, having specialized parts like a stomach and intestine for processing.
• Circulation:
  • Closed system: Blood stays within vessels, pumped by a heart, and carries oxygen with hemoglobin.
  • Open system (most species): A heart pumps fluid that flows freely within the body cavity.
• Excretion:
  • Special tubes (metanephridia) filter and remove waste from the blood.
  • Other specialized tubes (nephridia) also remove waste from the blood.
• Gas Exchange:
  • Moist skin acts as a breathing surface; oxygen from the skin is moved by the blood system.
  • In water, special structures called gills (in the mantle cavity) are used for breathing. This mantle cavity can also function as a lung on land.

Insects and Spiders

• Circulation: A heart pumps fluid (not true blood) that flows freely within the body.
• Excretion: Special tubes (Malpighian tubules) remove waste from the body fluid.
• Gas Exchange: Aquatic forms have feathery gills. Land forms breathe through a network of tubes (tracheal tubes) throughout the body, while spiders have specialized structures called book lungs.

Animals with a Simple Gut (Short Digestive Tract with Mouth and Anus)

• Circulation: Fluid in the body cavity moves nutrients around.
• Excretion: No special waste removal organs. Waste diffuses out from the body fluid and through a water-based internal system.
• Gas Exchange: A water-based internal system helps with gas exchange.

Vertebrates

• vertebrae: series of skeletal segments in a backbone
  • sing. vertebra
• amniotes: animals that produce amniotic eggs or can reproduce on land
  • incl. reptiles, birds, and mammals
• amniotic egg: waterproof egg w/ shell, which allows vertebrates to reproduce on land

Phylogenic Tree

Project Notes

Refer to slides for better clarity on Canva

Project: Class Reptilia — Reptiles

Defining Characteristics

• vertebrate
• internal fertilization: fertilization of egg happens inside body
• scales cover part or all of the body
• reptiles known to shed their scales throughout their lifetime
• reptile scales contain beta-keratin
• typically cold-blooded
  • change temp. by moving to warmer or colder environments
• if reptile lays eggs (most of them do), they lay soft-shelled eggs
• has lungs for breathing, no gills
• adapted to terrestrial environment
• reptiles produce amniotic eggs
• amniotic eggs: eggs w/ a special membrane and a shell to prevent embryo dehydration
  • allows reptiles to lay eggs on land

Evolutionary Origins

• Oldest known common ancestor to both reptiles and amphibians: Casineria
• reptiles said to derive from a common ancestor during the Middle Pennsylvanian Epoch (~312-307 mya)
• earliest undisputed reptile: Hylonomous and Paleothyris
• sister group to reptiles taxonomically: Synapsida (mammal-like reptiles)
• for mil. of yrs., reptiles and synapsids were similar
  • but over time, their lifestyles diverged and mammals arose from synapsids
• huge diversification of reptiles during the golden age of the dinosaurs, or the Mesozoic Era (biped dinosaurs were a thing)
• “Age of Reptiles,” the Mesozoic Era (251-65.5 mya)
• The earliest snakes evolved during the Middle Jurassic Epoch (174.1-163.5 mya)

Example: Massassauga Rattlesnake

Scientific name: Sistrurus catenatus

• Ontario’s only venomous snake
• Length: 47.2- 47.6 cm
• Grey to brownish grey with darker blotches along back and several rows of alternating blotches along sides; blotches edged in white
• Pit on each side of head between eye and nostril for heat sensing
• Distinct segmented rattle
• Tail thick, squarish; does not taper to a point like all others
• Does not always rattle a warning; relies on pattern and remaining motionless to go undetected
• Heavy-bodied; often found coiled
• Belly black
• Lives in different types of habitats including tall grass prairie, bogs, marshes, shorelines, forests and alvars
• Cold-blooded (ectothermic); require open areas to warm themselves in the sun
• Skin covered with scales; Dry smooth texture; keeled (ridged down the center) giving it a rough appearance
• Move by muscular contraction with the help of elongated scales on their abdomen
• Vestigial left lung, one functional lung
• No limbs, external ears, or eyelids

Example: Snapping Turtle

Scientific name: Chelydra serpentina

Physiology

• Largest freshwater turtle in Canada
• Average shell length: male: 36 - 43 cm / female: 28 - 37 cm
• Mass, male: 10 - 20 kg / female: 5 - 9 kg
• Appearance: Large, prehistoric-looking
• Shell relatively flat and brown during adulthood
• Shell color: black, olive, or brown (often covered in algae/moss)
• Skin colour: grey, brown, black / underside: white, cream, tan
• Triangular spikes along tail
• Prominent shell ridges
• Long neck and large head
• Webbed feet with long claws
• Sex determined by incubation temp. of embryos during a specific time of development
• Males produced at 23 - 28 C
• Females develop at cooler or warmer temps.
• They can see wider ranges of colors than humans
• Tetrachromacy color vision: E.g. they can see multiple shades of red

Habitat & Behaviour

• Native to southern Canada from eastern Saskatchewan to Nova Scotia, also found in eastern U.S.
• Active from April to Sept.
• Spend most of life in shallow waters (hide in mud and leaf litter, breathe with nose exposed)
• Not strong swimmers
• Usually walk on bottoms of ponds and rivers
• Nesting Season: Early to mid-summer
• Females travel overland to find nesting sites
• Frequently use man-made structures:
• Gravel road shoulders
• Dams
• Aggregate pits

Cool Facts

• Algae often grows on shell, helping with camouflage
• Cannot retract fully into shell; instead, they snap at threats
• Poorly known in wild
• Some over 100 years (based on Algonquin Park data)
• Take 15–20 years to reach maturity → adult deaths severely impact population
• High risk of being hit by vehicles
• Eggs near urban/agricultural areas often eaten by predators

Project: Class Amphibia — Amphibians

Defining Characteristics

• can exploit both terrestrial and aquatic environments
• name derived from Greek word amphibios, meaning “living a double life”
• typically has moist skin
• typically rely heavily on respiration (breathing) through the skin
• known to possess a double-channeled hearing system
• green rods in retinas to discriminate hues and two-part teeth
• eggs typically laid in water, young larvae develop in aquatic environment before moving out of environment

Evolutionary Origins

Tiktaalik

• first appeared ~340 mya during the Middle Mississippian Epoch
• the earliest groups to diverge from ancestral fish-tetrapod (fish w/ 4 feet) organisms, like the Tiktaalik
• Early tetrapods developed joints, stronger skeletons, and a flexible neck to support land movement
• transition from fins to limbs took over 80 million years, beginning in the Devonian Period
• Tiktaalik: intermediate form between fishes having fins and terrestrial animals having legs
• fossil evidence shows that amphibians arose from a lobe-fished lung ancestor ~365 mya
• amphibians were dominant land vertebrates for over 100 my, known as the “Age of the Amphibians”
• Frogs and salamander-like species appeared in the Triassic and Jurassic periods, with modern families emerging in the Cenozoic Era
• arrived during evolution of animals from aquatic environs. toward terrestrial environs.

Example: Golden Poison Dart Frog

Scientific name: Phyllobates terribilis

• Considered one of the most toxic animals on Earth
• Size: 4.7 - 5.5 cm, Mass: 30 g
• Protruding eyes, No tail and claws
• Named terribilis to warn about its terrible poison
• Habitat: Tiny plot in Chocó rainforest on Pacific Coast of Columbia
• Has enough poison to kill 20,000 mice
• Smooth, moist skins, colour: yellow, orange, pale green
• Lives up to 10 years
• Large eyes compared to body size
• Short vertebral columns
• Gets poison from poisonous food, insects and plants
• Cutaneous respiration (through skin)
• Males dance to attract females, attracted females fight each other to get male, female rubs snout and back of frog before they mate
• Eggs laid on forest floor, male carries hatched tadpoles into a water source
• Diet controls insect populations and prevents overconsumption of plants