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BIOL 202 Study Guide - Final Guide: Passerine, Pennaceous Feather, Kidney Development

Course Code
BIOL 202
Laurene M Ratcliffe
Study Guide

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from 2016 class Google doc
1. Introduction
Four main steps:
Zygote divides to form a blastula (a fluid-filled ball)
Cells at the top (animal pole) are smaller and darker coloured; cells at the bottom
(vegetal pole) are larger and contain more yolk (nutrients provided by the ovary)
Cells remain unspecialized (totipotent)
oCells of the blastula move inward at the blastophore to form a gastrula, a fluid-filled ball
with 3 cell layers
Endoderm (gut lining and derivatives, germ cells)
Ectoderm (epidermis, nervous system)
Mesoderm (everything else)
The 3 body axes are now defined:
oThe blastophore will form the anus; the mouth will form at the opposite end
oThe animal pole will form the back; the vegetal pole will form the abdomen
oCells are still totipotent, but their fates are determined
oDorsal mesoderm cells aggregate into a rod-like structure (notochord – support)
oThe notochords induces the dorsal ectoderm to fold, forming:
The dorsal neural tube (central nervous system)
Neural crest cells (other nervous system components)
Mesoderm flanking the notochord becomes segmented into somites (skeleton, skeletal muscle)
Pharyngeal pouches form along the pharynx (gills, thyroid)
The brain differentiates into 3 lobes (five brain lobes)
Ectodermal placodes form at the head (eyes, ears, nostrils)
The final product of neurulation (neurula or pharyngula) is very similar in all vertebrates
oLongest stage in all animals
oEmbryonic cells specialize, forming tissues, organs and organ systems
Differential cell division, growth and death results in different body shapes
2. Organ Systems
1. Integumentary system: functions in protection, communication (pheromones,
sending/receiving information with environment), respiration, excretion,
a. Includes two main multicellular layers (epidermis and the dermis),
blood vessels, nerves, mucous glands
2. Skeletal system: functions in support, protection and movement
a. Originally made of cartilage and included only gills and axial skeleton
(notochord, cranium and vertebrae)
b. Bone appeared early in vertebrate evolution
i. Endochondral (laid down within cartilage)
ii. Dermal (laid down by the dermis)
3. Muscular system: functions in support and movement

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a. Includes three muscle types:
i. Smooth (involuntary; usually visceral)
ii. Striated (skeletal; usually somatic, multinucleate)
iii. Cardiac (heart)
4. Digestive system: functions to release nutrients from food, process and store
nutrients, and neutralize toxins
a. Originally included only the mouth, pharynx (everything comes
together), esophagus, stomach (except in lamprey- Petromyzontida),
small intestine (nutrient absorption), liver (nutrient stored and
transported to blood), pancreatic cells and cloaca (exit)
b. Intestinal lining is folded into villi and microvilli (increase surface area
for better absorption); also have general folds which slow food down
and help mix it
c. Food is moved through the gut by peristalsis (contraction around gut
wall; smooth muscles run both around tract and up/down it)
5. Respiratory System: functions to exchange O2, CO2, heat, salts and N wastes
a. Originally involved the skin and vascularized foldings of the pharynx
(gills) with muscles for pumping water
6. Circulatory System: transports oxygen, nutrients, wastes, hormones,
antibodies, and heat
a. Is closed, originally single circuit
b. Originally the heart had 4 chambers (only one atrium and one
ventricle,plus conus arteriosis (muscular, prevent backflow) and sinus
venosus (collect blood from veins)
c. Lymphatic system recovers fluid and nutrients lost from the capillaries
7. Excretory System: functions in osmoregulation and elimination of metabolic
(nitrogenous) waste
a. Originally included the kidneys, skin, gills, and intestine
b. Functional unit of the kidney is nephron (a tubule lined with
specialized cells for filtering wastes from blood)
i. Bowman Capsule à renal tubule à collecting duct
c. The kidney develops sequentially from the somites. Under each one
of the somites is a nephrotome; this is where the main functional unit
of the kidney, the nephron, develops from.
d. Originally the pronephros served in embryo and the opisthonephros
(more adults) in the adult
e. Nitrogenous waste was probably originally eliminated as ammonia
(highly soluble, diffuses into water across the gills)
8. Reproductive System: functions in production and release of gametes, and
may support developing embryos
a. Gonads are multicellular (female = ovaries; male = testes)
b. Ancestrally, gametes were released into the coelom (body cavity) then
through pores near the cloaca (using muscle contraction)
c. Fertilization and development were originally external
9. Endocrine System: function in communication and coordination
a. Information transfer is slow, general, and long-lasting through
chemical signals (hormones and pheromones)
b. Includes endocrine (no ducts) and exocrine glands (ducts)
c. Originally only the pituitary

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d. Pineal (coordinates daily and seasonal rhythms) and thyroid (controls
metabolism and homeostasis) plus scattered specialized cells
10. Nervous system: functions in obtaining information from the environment and
coordinating body activities
a. Information is transferred by electrical signals and is rapid, specific,
and short lasting
b. The basic units are neurons which includes three types
i. Sensory (receptor) – pick up information from
ii. Motor (effector) – transmit information to muscles/nerves
iii. Interneurons – transport b/w motor and sensory
c. Two major components
i. Central nervous system (info, processing)
ii. Peripheral nervous system (cranial and spinal nerves),
including motor (ventral) and sensory (dorsal) roots. Which in
turn is made up of
1. Somatic system (body wall and appendages)
2. Autonomic system which includes
a. Sympathetic system (“fight or flight”): reacting to
environment, speeds up heart, increases blood
flow to heart, etc; react to stress
b. Parasympathetic (rest & digest): in control when
not reacting to environment; maintain while body
at rest
d. The brain includes basic sections
i. Telencephalon including olfactory lobes and bulbs
(olfaction; receives chemical info from mouth/nose), cerebrum
(voluntary movement, learned behaviour and corpus striatum
(instincts?) ii. Diencephalon including
the thalamus (sensory relay between parts of brain coordinating
info), hypothalamus (visceral integration; coordinates diff parts
of body), pituitary (coordinating body activities), pineal
Mesencephalon - originally optic lobes
iii. Metencephalon including the cerebellum
(hearing/balance/orientation/motor coordination), and pons (co-
ordination of cerebrum and cerebellum)
iv. Mylencephalon comprising the medulla oblongata (reflex
centres for basic functions)
e. Nervous system also includes receptors for taste (chemoreceptors),
smell (chemo), touch (mechanoreceptors), temp (thermoreceptors) as
well as multicellular sense organs for
i. Photoreception, including colour and UV vision (not in
humans but can help animals find food and is use in mating
ii. Eye including a cornea, lens, iris, and retina
lens: produce clear picture on retina
pupil: regulates intensity of light entering eye
retina: sheet of photoreceptors and neurons lining back of eye
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