Chapter 21- Environmental regulation in animal development - PowerPoint PPT Presentation

About This Presentation
Title:

Chapter 21- Environmental regulation in animal development

Description:

Phenotypic plasticity- (cont.) c. _____-dependant sex determination Recall Temperature-dependent sex determination in reptiles (Ch. 17) ... – PowerPoint PPT presentation

Number of Views:910
Avg rating:3.0/5.0
Slides: 16
Provided by: Department847
Learn more at: https://www.ux1.eiu.edu
Category:

less

Transcript and Presenter's Notes

Title: Chapter 21- Environmental regulation in animal development


1
Chapter 21- Environmental regulation in animal
development
1. Many examples of environmental regulation
exist
  • Red abalone- must bind coralline red algae to
    begin ___________________
  • Mosquito- _________________ triggers egg
    production
  • ______________________________
  • Algae provides photosynthetic energy to amphibian
    eggs when in tight clusters
  • A bacterium multiplies only in leaf hopper
    __________
  • No bacterium embryonic death due to lack of
    _________________ development

2
Nitrogen fixing ________ provide nitrogen to
legumous plants (e.g. bean plants)
1. environmental regulation (cont.)
  • Aphids hatch only _________ in the spring, but
    male and female are hatched in the autumn
    (mechanism unknown)
  • Many insects use __________- a suspension of
    development due to harsh conditions (e.g winter
    condition)
  • Diapause is not triggered by harsh conditions,
    but before the harsh conditions arrive
  • Gravity/pressure
  • A chick embryo requires proper positioning to
    _________________________
  • Also effects development of bones in chicken

3
2. ____________________- express distinct
phenotypes depending on circumstances
Termed ______________
Low density phenotype
a. _______________ dictates grass hopper
development
High density phenotype
_________ phenotype
Fig. 21.6
b. ______ dictates wing color in certain
butterflies
_________ phenotype
Fig. 3.3
4
2. Phenotypic plasticity- (cont.)
c. ______________-dependant sex determination
Recall Temperature-dependent sex determination in
reptiles (Ch. 17)
  • Crocodiles- temperature extremes result in
    female

Advantage- increase sexual reproduction if ____
malefemale ratio
Disadvantage- less adaptable to slight
environment change (e.g. ______________)
  • Blue headed Wrassse (reef fish) -
  • If wrasse reaches reef with males, it develops
    into _____
  • If wrasse reaches reef without males, it develops
    into ___
  • If male dies, largest female becomes male within
    _______

5
d. __________-induced polypheism
a. Organisms change shape in response to soluble
factors released by predators
Fig. 21.13
typical
Predator induced
Carp
Mollusk
Barnicle
???
Daphnia
???
Survival Rate (typical/induced)
______
No predation until 50 of typical morphs eaten
_____
_____
____
____
6
3. Predator-induced polypheism (cont.)
b. Mammalian immunity
  • A foreign object (antigen) is recognized by a one
    in __ _________ B-cells
  • Only the B-cell that recognizes the antigen will
    __________ and secrete specific antibody to
    _________ the antigen
  • The immune system _____________ its foreign
    invaders

7
4. Learning is an environmentally induced system
  • New neurons are produced
  • in _______ learning a song
  • in ________ learning activities

b. Visual pathway development is affected by
_______
  • A flash of light seen by a cortical neuron right
    eye is also seen by the corresponding cortical
    neuron in the left eye
  • Kitten experiments
  • If sew right eye of newborn closed for ________,
    they were functionally ______ in right eye
  • If sew both eyes of newborn closed for 3 months,
    vision remains (though weak) in ________

8
4. Learning is an environmentally induced system
  • Kitten experiments (cont.)
  • If sew either eye shut after first three months-
    __ __________
  • Thus, synapses have been stabilized by 3 months
  • Critical window of development is 4 weeks to 3
    months
  • Thus, not all development is encoded in the
    ______
  • Some is the result of ___________

Two key principles-
1. ______________ are made prior to when the
animal sees
2. __________ plays key role in determining
whether neuronal connections ____________
Also- the _________________ phenomenon is due to
learning
9
5. Environmental disruptions to development
  • About _____________ of human conceptions survive
    to term
  • About ____ of human babies have a recognizable
    deformation (normally in limbs, lungs or face)
  • Abnormalities caused by genetic mutations agents
    are called ____________ (e.g. Downs syndrome,
    aniridia (Pax6 mutation))
  • Abnormalities caused by exogenous agents are
    called ________

Examples-
  • Skunk cabbage induced _______ in sheep

In Humans
_______________________
10
5. Disruptions (cont.)
a. Retinoic acid as a teratogen
Accutane-for treating severe ____
________ women of childbearing age have used
Accutane
1985 study of pregnant Accutane users
  • ____ normal
  • _____aborted spontaneously
  • _____ with anomalies- absent ears, small jaws,
    cleft palate, and/or CNS problems

Estimated that__ of pregnancies in America are
unplanned
11
b. Alcohol is a teratogen
CH3CH2OH
Fetal Alcohol Syndrome
  • Fetal alcohol syndrome (FAS) is __ most prevalent
    type of mental retardation (behind fragile X and
    Down Syndrome) ______ children in USA
  • Estimated that _______ of children born to
    alcoholic mothers will have FAS
  • FAS children have mean IQ of __ at 16.5 yrs,
    they have vocabulary of ___ yrs

Misshapen eyes, flat nose, long upper lip
Huge problem in South Africa due to alcohol-based
economy
12
c. Pathogens as teratogens-
  • ______ can cause deafness, heart malformations
  • _____________ and cytomegalovirus can cause
    deafness, blindness, mental retardation
  • Syphilis can cause deafness or death

d. Chemicals as teratogens-
  • ________________, and zinc are common ones
  • In Kazakhstan (former Soviet Union) nearly __ of
    population have extensive chromosome breakage due
    to industrial production at all costs

13
e. Estrogen
  • DDT is a banned insecticide that can act like
    ________
  • DDT is linked to increased incidence of
    __________ and decreased _____ ________
  • Dioxin (dumped at Times Beach west of St. Louis)
    is linked to increased _____ _____ and decreased
    ____________

1985-Industrial plant in Italy explodes-
  • Breast cancer ____________in immediate perimeter
  • Breast cancer ___________ in surrounding area

14
e. Estrogen (cont.)
  • _____________ (used to harden plastics used in
    plumbing and milk/orange juice containers)-
    replaces role of estrogen to induce certain
    cultured cell to divide
  • PCBs (previously used as refrigerants) banned in
    1970 due to cancer-causing ability in rats yet
    remain in environment
  • Blamed for reduced reproductive capacities in
    seals, mink and fish

Dramatic increase in deformed frogs in US- Due to
toxins in water?
15
Other teratogens
  • ____________(fallout)
  • Infectious agents- Herpes simplex II,
    cytomegalovirus, rubella
  • Drugs- alcohol, aminopterin, chlorophenyls,
    tetracyclines, thalidomide
  • Other possible teratogens- _______ ___________,
    lithium, zinc deficiency
Write a Comment
User Comments (0)
About PowerShow.com