Exam Four Review Flashcards
What are Choanoflagellates?
Single-celled sister group to animals
colonial organism
Animals evolved to be mulitcelluar independent from them (paraphyletic)
Characteristics of Animals
Ingest foods and digest internal using enzymes
Multicelluar w/no cell wall; held together by proteins (collagen, cadherins, etc.)
Formation of blastula/gastrula (hollow bal of cells that inents to form cavity
Origins
–770 MYA
–560 MYA: 1st fossils
–542 MYA: 1at modern animal phyla appears during Cambrian Explosion
Earliest Animals
Gastrula-like with specialized cells for reproduction
–sponges have specialized cells w/no tissue+symmetry at maturity
–ancestral animals had radial symmetry and tissue similar to jellyfish
–two tissue layers (endoderm = gut lining and ectoderm = outer layer)
Invertabrates
Animals with no backbone
Ancestral characteristic
Paraphyletic grouping (closer to vertebrates then some invertebrates)
What phylum is the first-branching lineage of animals?
Phylum Ctenophora (Comb Jellies): similar to true ‘jellyfish’ (Cnidaria) and big gastrula
–specialized tissue and radial symmetry like jelly fish but not closely related
–have nerves and muscle tissue but they works differently then other animals
–basal animal lineage supported by gene order on chromosomes
Phylum Porifera (Sponges)
–No specialized tissue and MOST have no symmetry at maturity (some do)
–Filter gallons of water through body cavities to catch food particles
–structural support and predator defense from silica or calcium carbonate spicules
–internal cells (choanocytes) are identical in order to form Choanoflagellates
–simiplified over time
Phylum Placozoa
–pancake like
–behave like multicellular amoeba and move w/cilia
–branched off after Ctenophora and Porifera; rest of simplification/reduction of an ancestor w tissue
Phylum Cnidaria (Jellyfish)
–radial symmetry and tissues (endoderm and ectoderm)
–few have cnidocytes (stinging cells that capture food and produce venom)
–sessile (anchored non-moving) and floating forms (jellyfish, anemones, corals, and hydra)
Bilateral Symmetry
evolved after sponges and Cnidarians had already diverged from other animals
–three embryonic tissue with a mesoderm layer filling in a speace b/w the endonderm and the ectoderm
Bilateral Animals Characteristics
Dorsal (top) side and ventral (bottom) side
Right/left side are symmetrical
Anterior (head) and posterior (tail) ends
Distinct mouth often leads to cephalization, the development of a head
Acoela
Basal Lineage of Bilateria
Bilaterally symmetric flattened worms (probally waht ancestral bilateral animals look like)
Bilateral Animals are Split into Two Lineages Based on Embryonic Development
Prostones
“first mouth”
initial indentation during gastrulation becomes the mouth
anus forms second after the gastrointestinal tract has grown through to the other side
Lophotrochozoa and Ecdysozoa
Bilateral Animals are Split into Two Lineages Based on Embryonic Development
Deuterostomes
“second mouth”
Becomes the anus during gastrulation
First recognizable feature
Lophotrochozoa
One of the major groups of Protostomes
Named after larval forms common to some of the phyla
Ex) Phylum Platyhelminthes, Mollusca, and Annelida
Ecdysozoa
One of the major groups of Protostomes
Ecdysis: molting skin/exoskeleton
Ex) Phylum Nematoda, Arthropoda
Phylum Platyhelminthes (Flatworms)
Lophotrochazoa–>Protostome
Simple body plan is similar to Acela and ancestral bilateral animals
Human parasites (tapeworm, liver flukes)
Phylum Mollusca (Snails and Slugs, Oysters and Clams, Octopi and Squid)
Lophotrochazoa–>Protostome
Largest marine phylum; freshwater and terrestrial
Anatomically seperated into head, foot, and mantle
Bivalves, Gastropods and Cephalopods– gastro = stomach, cephalopod = head, pod = foot
Soft bodied protected by a hard shell (slugs)
40% of recorded animal extinction
Phylum Annelida (Segmented Worms)
Lophotrochazoa–>Protostome
Segmented bodies–convergent evolution w/arthropods
Earthworms, Leeches, Tubeworms, etc.
Tubeworms have chemoautotrophic bacteria livin in their tissue; fomr base of the foos chain in some spaces at the bottom of the ocean
Phylum Nematoda (Roundworms)
Ecdysozoa–>Protostome
Parasites of plants and animals
C. elegans
Research organism
1st animal genomes to be completely sequence
Phylum Arthropoda (Jointed animals)
Ecdysozoa–>Protostome
Segmented invertabrates w/jointed appendages and exoskeleton
Crustaceans (crab, lobster, shrimp)
Chelicerates (horseshoe crab, spider, ticks)
Myriapods (centipedes, millipedes)
Hexapods (insects)
Trilobites (extinct)
2/3 of all animals; found in nearly all Earths habitats
Exoskeleton
external skeleton that protects the body
composed of polysaccharides chitin (cell wall) infused w/calcium
Class Insecta
Subphylum Hexapoda
Class of Arthropoda that contains over half animal species
Successive nymh stages that looks like smaller version of adult selves
4 most diverse orders of insects go through complete metamorphosis (pupa–>adult)
Insects (Pros and Cons)
Cons
vector for disease
biting and stinging
Economic and agricultural damage
Pros
pollinator
diverse, abundant, and integral part of most food chains
Phylum Echinodermata
Slow moving marine animals (sea stars, sea cucumber, etc.)
Bilateral symmetry
Exoskeleton made of hard calcium carbonate plates
Phylum Chordata
Derived characteristics: notochord, dorsal hollow nerve cord, muscula most-anal tail, pharyngeal gill slits
Some are only present during embryonic development
Simple Chordates
Lancelets: ancestral characteristics (no head, brain, backbone, etc.)
Sea Squirts: start out as tadpoles w/4 chordates characteristics that develop into permanently anchored filter feeders
Vertebrates
Subphylum of Chordata
Name derived from vertebrae
Have cranium and backbone
First Branch of Vertabrates = Jawless Fish
No jaws and no paired fish
Hagfish
No vertabrae; slimy
No eyes
Lampreys
Simple vertebrae
Cartilaginous Fish (Shark, Rays, etc.)
Don’t have fully hardened bones but share the following characteristics with bony vertabrates
Calcium-infused cartilage
Jaws
2 sets of paired appendages (pectoral and pelvic fins in places homologous to arms and legs)
Bony “Fish” (Osteichthyes)
Includes most living land vertebrates (human)
Some aren’t fish
Ray-finned Fish and Lobe-fins
Ray-Finned Fish
Bony “Fish”
Aquatic fish
Fins supported by long flexible rays not bones or muscles
Swim Bladders (Lungs)
Most diverse group of vertebrates
Zebra fish
Lobe-Fins
Bony “Fish”
Muscualr pectoral and pelvic fins
Coelacanths: fossil records; bottom of the ocean; swim bladder filled w/oil to keep from floating up
Lungfish: closest relative to land vertebrates; depend on lungs to breath
Tetrapods: Land vertatbrates
Tetrapods
Terrestrial Lobe-fins
Four limbs and hands w/digits
Amphibians
Convergent evolution: legless amphibians that look like worms or snakes
Closely tied to water
Delayed development of limbs derived from amphibians (not ancestral)
Breath through skin a maturity
Amniotes
Terrestrially adapted egg (amniotic egg) that contains specialized membranes that protects the embryo from drying out byt allow for gas exchange
Two Clades: Reptiles and Mammals
Projections of Keratin (scales, feathers, hair, fingernails)
Rib cage ventilation
Reptiles
Amniotes
Turtles, lepidosaurs (tuataras, lizards, snakes) , archosaurs (crocodilians and dinosaur including birds)
Scales/feathers that create a waterproof barrier
Lay eggs on land
Turtles
Box-like shell (upper and lower)
No teeth
Lepidosaurs (Tutaras, Lizards, and Snakes)
Lizards: most abundant/diverse reptile (second to birds); some independently lost legs (convergent evolution)
Snakes: legless; evolved from lizard-like ancestor (paraphyletic)
Tuataras: old; lizard-like lineage isolated to a few Pacific Islands
Archosaurs
Crocodiles and Dinosaurs
Crocodiles: retain primitive charatcteristics (lizard body)
Dinosaurs (Birds)
Most diverse tetrapods (10,000 species)
Adaptation: hollow bones, no teeth, no bladder
Warm blooded (170 MYA)
Mammals
5,400 species
Mammary glands produce milk
Hair for insulation
Differentiated teeth
Warm blood (convergent evolution with dinosaurs)
Monotremes (Major Mammal Lineage)
Primitive egg-laying
No nipples
ex) echidnas and platypus
Marsupial (Major Mammal Lineage)
Embryo born early, finishes development within maternal pouch (marsupium)
Common ancestor with Placental Mammals that didn’t lay eggs (hatch internally)
Placental Mammals (Major Mammal Lineage)
Complete embryonic development in uterus and joined by placenta
Common ancestor with Marsupials (only those that hatch eggs internally)
Primates
Basal primates were nocturnal, tree dwelling, insect-eaters
binocular vision and gripping hands came later due to selection of lifestyle
Originally an Old World group; more closely related to apes (including humans)
Apes (Gibbons, Orangutans, Gorillas, Chimpanzees and Bonobos, and Human)
Vestigal tail that stops growing in early development
Gorrilla + Chimps + Humans = African Apes
Chimps and Bonobos are humans closest living nonhuman relative
Hominid Evolution
Fossil human-like apes are more closely related to humans then chimps
Seperate humans from other African Apes
Bipedal (evolved before increased brain size)
Bigger brain/skull
Homosapien skull indistinguishable from modern human skeleton (200,000 years ago)
Exchange with the Environment
Effected by size and shape of animal
Exchange occurs when substances dissolved in an aqueous medium and are transported across cell membrane
Exchange Surfaces
connect to the environment through openings in a multicellular animal
internal cell are connect to exchange surfaces by circulatory fluids and interstitial fluids
Endocrine System
maintain homeostasis
excretes hormones
Hormones
slower long-acting repsoe to stimuli
secreted into the circulatory system that communicates regulatory messages
only target cells with the proper reaction for hormones can respond
Effects of Hormones
Same receptors in very different types of cells, cell response differs
Different receptors on same type of cell can cause different response
Nitrogenous Waste
products of protein and nucliec acids must be removed from the body
Ammonia
Toxic; requires acces to a lot of water; common in aquatic animals
Urea
Produced in the liver
Less toxic
Carried to kidney where concentrated and excreted with minimal loss of water
Aquatic animal (sharks), amphibians, mammals
Uric Acid
Insoluble in water
Secreted as a paste with very little water loss
Reptiles (including birds), insects, land mollusks
Aminal Nutrition
Chemoheterotrphs
3 nutritional needs
–fuel for cellular work
–organic raw material for biosynthesis
–essential nutrients
Open Circulatory Systems
invertebrates, insects and other arthropods, most mollusks
Circulatory Fluid (hemolymph)
Bathes the organs directly with no separation from interstitila fluid
Closed Circulatory System
Annelids, squids and octopuses, and vertebrates
–Circulatory (blood) is confine to vessels distinct from interstitial fluid
–More efficient at transport fluids to cells
–Can work at higher pressure (and speed)
Arteries
thicker walls accommodate high pressure of blood pumped from heart
Veins
thinner-walled, blood flows back to the heart with help from muscle
Capillaries
very thin, facilitates exchange with the interstitial fluid
branch like
blood flow is slow; low pressure
Mammalian Respiratory System
Air passes through the pharynx into trachea, bronchi, bronchioles, and alveoli where gas exchange happens
Gills on Aquatic Animals
ventilation: movement of water across the gills
Countercurrent flow of blood and water
How do birds breath
air sacs that act like small bellows that keep air flowing through the lungs continuously
able to survive better at lower oxygens pressures than mammals
Innate immunity
present before exposure to pathogens
barrier defenses: mucus, skin
internal defense: WBC’s (macrophages), natural killer cells
Aquired Immunity
Specific response to specific pathogen
B-cell lymphocytes
T-cells
Neuron cell body
nucleus and organelles
Dendrites
brancked extensions receive signal from other neurons
Axons
the end of a neurons that divide into multiple terminals to communicate with the other cells at synapse
Action Potential
1) when nerve is stimulated sodium channels
2) sodium ions rush into the cell (neg charge)
3) brief positive charge on the inside of the cell membrane and negative charge on the inside = action potential
4) all or nothing response
Neurotransmitters
presynaptic and postsynaptic neuron usually by the way of chemical transmitters
