SlideShare a Scribd company logo
1 of 19
Development
and the
Environment
Developmental Plasticity
• The Environment plays as much a role in development
as our genes
• Phenotypic plasticity is when an organism can react to
the environment by changing its state, form, or activity
• Developmental plasticity is when this occurs in the
larval stage
• a good example of this is metamorphosis- the
same genes are present in the adult and larvae,
but you find different manifestations in
phenotype
Types of Phenotypic Plasticity
• The are two main types
• Reaction Norm- the genome has a continuum of phenotypes,
and the environment will determine which will form
• Think of muscle growth when one works out.
• Polyphenism- This is an on/off or an either/or situation. It is
not on a continuum. There are various types such as:
• Diet-induced
• Methylation
• Predator induced
Diet-Induced Polyphenism
• The caterpillar Nemoria arizonaria will look like a twig or an oak flower depending on
what it eats.
• The flowers are seasonal, so it doesn’t want to look like a flower when there are no
other flowers out
• This depends on eating young leaves
• If older leaves are eaten, the caterpillar will look, instead, like a twig
• Honey bees feed a royal jelly containing royalactin to bees destined to become queen.
• Royalactin stimulated egg production in the queen
continued
• Dung beetle larvae eat food left by the mother
• The quality and the quantity of the food left in a particular hole determines the amount
of juvenile hormone made in the last molt
• This determine the presence of horns or not
• Recall that methyl groups can be added to segments of DNA. In general, it will repress
transcription of the gene
• This will cause changes in the phenotype
• Some supplements (like folic acid) are methyl donors
Predator-Induced
Polyphenisms
• When water fleas detect chemicals from predatory fly larvae, they alter
their development
• They will make spiked heads and tails which make them difficult to
swallow
Predator-Induced Polyphenisms
• When embryos of the Costa
Rican Red-Eyed tree frog sense
vibrations from a snake crawling
on a leaf, the eggs prematurely
open and the larvae fall to the
water below
Temperature as an Environmental Agent
• In some species, the decision on the development of testes or ovaries
depend on temperature
• For example, for crocodiles, extreme temperatures will produce females
whereas moderate temperatures produce males
• In the Malawian butterfly Bicyclus anynana, there is a dry season morph in
which the butterfly camouflages in dead leaves on the forest floor
• The wet season morph has eyespots on their wings and tend to fly more
• This decision is made in the pupal stage
Larval Settlement
One type of cue is a biofilm. These are often sheeting of
bacteria
This may be why barnacles form on the hull of
boats for example
Some marine larvae can suspend development until they
experience a particular environmental cue. This is called
larval settlement
Stress as an Agent
• The Spadefoot Toad will change their development
according to an environmental stress
• This depends on the water levels in the ponds
• Tadpoles will go through metamorphosis at different
times based on the available water in the pond
• When the water levels in the pond drop, the tadpoles
sense it and develop a wider mouth and stronger jaws
• They become carnivorous (cannibalistic) and morph
very quickly
Developmental Symbiosis
A symbiotic relationship is
where an organism comes to
depend on another
• Usually, the host the larger
of the two
• The symbiont is the smaller
of the two
There are two types:
• In parasitism, the symbiont
benefits at a cost to the host
• In mutualism, both the
symbiont and host benefit
from the relationship
Endosymbiosis
• In Endosymbiosis, the symbiont will live in (or partly in)
the host. There are two typical examples of this in plants:
• Nitrogen-Fixing bacteria live in the roots of many
plants (you can find particular high amounts in
legumes
• These bacteria ‘fix’ nitrogen in the air by
reducing its triple covalent bond to a single
bond compound so the plant can use it.
• The bacteria, in turn take sugar from the plant
Endosymbiosis
• Mycorrhizae fungi are associated with most plant roots
(although there are different species of fungi
associated with different plants
• These fungi increase the area in which the plant
can obtain water at the roots
• In turn, the fungi consume sugar from the plant.
Mechanisms of
Developmental Symbiosis
Vertical Transmission is the
transfer of symbionts from
one generation to the next
• Some symbiosis is obligate
mutualism- meaning that
they can not survive
without each other.
• An example of this can
be found in lichens (a
symbiotic relationship
between fungi and algae)
Horizontal Transmission is
when one becomes infected
by other members of the
species
• Humans acquire some
symbionts as they travel
through the birth canal.
Others can be transmitted
through contact with the
skin during breast feeding
Developmental
Symbiosis in
the Mammal
Intestine
In mice, bacteria help with cell differentiation. The gut
bacteria up-regulate transcription of many genes
Studies in mice show that without intestinal bacteria,
villi (the absorptive part of the intestine) will not be
vascularized and there will be no brush border enzymes
Gut bacteria is also important for mammalian gastric-
associated lymphatic tissue
Bacteria may be involved in things like brain formation
and reproduction.
Developmental
Symbiosis in the
Mammal
Intestine
Mammals have co-evolved with bacteria to the
point that our body phenotypes do not develop
without them
There are more bacteria in humans than we
have cells in our body
There are around 400 species of gut bacteria in
us
We are only beginning to understand how they
interact with us

More Related Content

What's hot

Hormnoes as mediator development
Hormnoes as mediator developmentHormnoes as mediator development
Hormnoes as mediator development
THILAKAR MANI
 

What's hot (20)

Zoologic al nomenclatures 5
Zoologic al nomenclatures 5Zoologic al nomenclatures 5
Zoologic al nomenclatures 5
 
Pattern formation in drosophila
Pattern formation in drosophilaPattern formation in drosophila
Pattern formation in drosophila
 
Taxonomic procedure.pptx
Taxonomic procedure.pptxTaxonomic procedure.pptx
Taxonomic procedure.pptx
 
Cell aggregation and differentiation in dictyostelium007
Cell aggregation and differentiation in dictyostelium007Cell aggregation and differentiation in dictyostelium007
Cell aggregation and differentiation in dictyostelium007
 
Taxonomic characters 7
Taxonomic characters 7Taxonomic characters 7
Taxonomic characters 7
 
PATTERN FORMATION
PATTERN FORMATIONPATTERN FORMATION
PATTERN FORMATION
 
Hormnoes as mediator development
Hormnoes as mediator developmentHormnoes as mediator development
Hormnoes as mediator development
 
Amphibian Metamorphosis
Amphibian MetamorphosisAmphibian Metamorphosis
Amphibian Metamorphosis
 
locomotion in protozoa.pptx
locomotion in protozoa.pptxlocomotion in protozoa.pptx
locomotion in protozoa.pptx
 
Lamarckism
Lamarckism Lamarckism
Lamarckism
 
Metamorphosis in Amphibians
Metamorphosis in AmphibiansMetamorphosis in Amphibians
Metamorphosis in Amphibians
 
osmoregulation in invertebrates.
osmoregulation in invertebrates.osmoregulation in invertebrates.
osmoregulation in invertebrates.
 
Darwinism and Neo Darwinism
Darwinism and Neo DarwinismDarwinism and Neo Darwinism
Darwinism and Neo Darwinism
 
Torsion in gastropoda
Torsion in gastropodaTorsion in gastropoda
Torsion in gastropoda
 
History & basic concepts db
History & basic concepts  dbHistory & basic concepts  db
History & basic concepts db
 
Comparative account of jaw suspension
Comparative account of jaw suspensionComparative account of jaw suspension
Comparative account of jaw suspension
 
Lamarckism and neolamarkism
Lamarckism and neolamarkismLamarckism and neolamarkism
Lamarckism and neolamarkism
 
Metamorphosis in Insects
Metamorphosis in InsectsMetamorphosis in Insects
Metamorphosis in Insects
 
Egg structure, types classification and cleavage types , sperm structure
Egg structure, types classification and cleavage types , sperm structure Egg structure, types classification and cleavage types , sperm structure
Egg structure, types classification and cleavage types , sperm structure
 
Species concepts 4
Species concepts 4Species concepts 4
Species concepts 4
 

Similar to BIO420 Chapter 24

Protitts chap 8 notes
Protitts chap 8 notesProtitts chap 8 notes
Protitts chap 8 notes
kleinkea
 
Chapter 6 marine microbes
Chapter 6 marine microbesChapter 6 marine microbes
Chapter 6 marine microbes
kleinkea
 
Chapter 6 marine microbes
Chapter 6 marine microbesChapter 6 marine microbes
Chapter 6 marine microbes
kleinkea
 
Reproduction in organism 2014 mohanbio
Reproduction in organism 2014 mohanbioReproduction in organism 2014 mohanbio
Reproduction in organism 2014 mohanbio
mohan bio
 

Similar to BIO420 Chapter 24 (20)

Class 11 chapter 2
Class 11 chapter 2Class 11 chapter 2
Class 11 chapter 2
 
Plant-Like Protist (Algae Intro..)
Plant-Like Protist (Algae Intro..)Plant-Like Protist (Algae Intro..)
Plant-Like Protist (Algae Intro..)
 
Environmental regulation in normal development of animals by mutaib siddiqui
Environmental regulation in normal development of animals by mutaib siddiquiEnvironmental regulation in normal development of animals by mutaib siddiqui
Environmental regulation in normal development of animals by mutaib siddiqui
 
Grade 11 biology plant kingdom
Grade 11 biology  plant kingdomGrade 11 biology  plant kingdom
Grade 11 biology plant kingdom
 
Protitts chap 8 notes
Protitts chap 8 notesProtitts chap 8 notes
Protitts chap 8 notes
 
Morphological organization and cell structure of Micro-organisms.
Morphological organization and cell structure of Micro-organisms.Morphological organization and cell structure of Micro-organisms.
Morphological organization and cell structure of Micro-organisms.
 
PLANT KINGDOM PPT.pdf
PLANT KINGDOM PPT.pdfPLANT KINGDOM PPT.pdf
PLANT KINGDOM PPT.pdf
 
Reproduction-PUC_II
Reproduction-PUC_IIReproduction-PUC_II
Reproduction-PUC_II
 
Reproduction in palnt and organisams
Reproduction in palnt and organisamsReproduction in palnt and organisams
Reproduction in palnt and organisams
 
How plants colonized the land and evolution
How plants colonized the land and evolutionHow plants colonized the land and evolution
How plants colonized the land and evolution
 
Class xi ch 2
Class xi ch   2Class xi ch   2
Class xi ch 2
 
Std 12 ch 1 reproduction in organism
Std  12 ch 1 reproduction in organismStd  12 ch 1 reproduction in organism
Std 12 ch 1 reproduction in organism
 
Std 11 biology chapter 03 plant kingdom
Std 11 biology chapter 03 plant kingdomStd 11 biology chapter 03 plant kingdom
Std 11 biology chapter 03 plant kingdom
 
Chapter 6 marine microbes
Chapter 6 marine microbesChapter 6 marine microbes
Chapter 6 marine microbes
 
Chapter 6 marine microbes
Chapter 6 marine microbesChapter 6 marine microbes
Chapter 6 marine microbes
 
Ch 01 - Reproduction in Organism || Class 12 ||
Ch 01 - Reproduction in Organism || Class 12 ||Ch 01 - Reproduction in Organism || Class 12 ||
Ch 01 - Reproduction in Organism || Class 12 ||
 
Reproduction in organism 2014 mohanbio
Reproduction in organism 2014 mohanbioReproduction in organism 2014 mohanbio
Reproduction in organism 2014 mohanbio
 
protista.pptx
protista.pptxprotista.pptx
protista.pptx
 
Chapter_3_Kingdom_Plantae.pptx
Chapter_3_Kingdom_Plantae.pptxChapter_3_Kingdom_Plantae.pptx
Chapter_3_Kingdom_Plantae.pptx
 
How Do Organisms Reproduce ? - Class 10 CBSE science (BIo)
How Do Organisms Reproduce ? - Class 10 CBSE  science (BIo)How Do Organisms Reproduce ? - Class 10 CBSE  science (BIo)
How Do Organisms Reproduce ? - Class 10 CBSE science (BIo)
 

More from BealCollegeOnline (20)

BA650 Week 3 Chapter 3 "Why Change? contemporary drivers and pressures
BA650 Week 3 Chapter 3 "Why Change? contemporary drivers and pressuresBA650 Week 3 Chapter 3 "Why Change? contemporary drivers and pressures
BA650 Week 3 Chapter 3 "Why Change? contemporary drivers and pressures
 
BIO420 Chapter 25
BIO420 Chapter 25BIO420 Chapter 25
BIO420 Chapter 25
 
BIO420 Chapter 23
BIO420 Chapter 23BIO420 Chapter 23
BIO420 Chapter 23
 
BIO420 Chapter 20
BIO420 Chapter 20BIO420 Chapter 20
BIO420 Chapter 20
 
BIO420 Chapter 18
BIO420 Chapter 18BIO420 Chapter 18
BIO420 Chapter 18
 
BIO420 Chapter 17
BIO420 Chapter 17BIO420 Chapter 17
BIO420 Chapter 17
 
BIO420 Chapter 16
BIO420 Chapter 16BIO420 Chapter 16
BIO420 Chapter 16
 
BIO420 Chapter 13
BIO420 Chapter 13BIO420 Chapter 13
BIO420 Chapter 13
 
BIO420 Chapter 12
BIO420 Chapter 12BIO420 Chapter 12
BIO420 Chapter 12
 
BIO420 Chapter 09
BIO420 Chapter 09BIO420 Chapter 09
BIO420 Chapter 09
 
BIO420 Chapter 08
BIO420 Chapter 08BIO420 Chapter 08
BIO420 Chapter 08
 
BIO420 Chapter 06
BIO420 Chapter 06BIO420 Chapter 06
BIO420 Chapter 06
 
BIO420 Chapter 05
BIO420 Chapter 05BIO420 Chapter 05
BIO420 Chapter 05
 
BIO420 Chapter 04
BIO420 Chapter 04BIO420 Chapter 04
BIO420 Chapter 04
 
BIO420 Chapter 03
BIO420 Chapter 03BIO420 Chapter 03
BIO420 Chapter 03
 
BIO420 Chapter 01
BIO420 Chapter 01BIO420 Chapter 01
BIO420 Chapter 01
 
BA350 Katz esb 6e_chap018_ppt
BA350 Katz esb 6e_chap018_pptBA350 Katz esb 6e_chap018_ppt
BA350 Katz esb 6e_chap018_ppt
 
BA350 Katz esb 6e_chap017_ppt
BA350 Katz esb 6e_chap017_pptBA350 Katz esb 6e_chap017_ppt
BA350 Katz esb 6e_chap017_ppt
 
BA350 Katz esb 6e_chap016_ppt
BA350 Katz esb 6e_chap016_pptBA350 Katz esb 6e_chap016_ppt
BA350 Katz esb 6e_chap016_ppt
 
BA350 Katz esb 6e_chap015_ppt
BA350 Katz esb 6e_chap015_pptBA350 Katz esb 6e_chap015_ppt
BA350 Katz esb 6e_chap015_ppt
 

Recently uploaded

一比一原版(Caltech毕业证书)加州理工学院毕业证成绩单学位证书
一比一原版(Caltech毕业证书)加州理工学院毕业证成绩单学位证书一比一原版(Caltech毕业证书)加州理工学院毕业证成绩单学位证书
一比一原版(Caltech毕业证书)加州理工学院毕业证成绩单学位证书
atedyxc
 
一比一原版(ASU毕业证书)亚利桑那州立大学毕业证成绩单学位证书
一比一原版(ASU毕业证书)亚利桑那州立大学毕业证成绩单学位证书一比一原版(ASU毕业证书)亚利桑那州立大学毕业证成绩单学位证书
一比一原版(ASU毕业证书)亚利桑那州立大学毕业证成绩单学位证书
atedyxc
 
一比一原版(UCSB毕业证书)圣塔芭芭拉社区大学毕业证成绩单学位证书
一比一原版(UCSB毕业证书)圣塔芭芭拉社区大学毕业证成绩单学位证书一比一原版(UCSB毕业证书)圣塔芭芭拉社区大学毕业证成绩单学位证书
一比一原版(UCSB毕业证书)圣塔芭芭拉社区大学毕业证成绩单学位证书
atedyxc
 
一比一原版(UC Davis毕业证书)加州大学戴维斯分校毕业证成绩单学位证书
一比一原版(UC Davis毕业证书)加州大学戴维斯分校毕业证成绩单学位证书一比一原版(UC Davis毕业证书)加州大学戴维斯分校毕业证成绩单学位证书
一比一原版(UC Davis毕业证书)加州大学戴维斯分校毕业证成绩单学位证书
atedyxc
 
Bahawalpur Culture.pptx pptx pptx pttx pttx
Bahawalpur Culture.pptx pptx pptx pttx pttxBahawalpur Culture.pptx pptx pptx pttx pttx
Bahawalpur Culture.pptx pptx pptx pttx pttx
AbdulNasirNichari
 
DSP Gold ETF Fund of Fund PPT - April'2024
DSP Gold ETF Fund of Fund PPT - April'2024DSP Gold ETF Fund of Fund PPT - April'2024
DSP Gold ETF Fund of Fund PPT - April'2024
DSP Mutual Fund
 
一比一原版(Concordia毕业证书)康卡迪亚大学毕业证成绩单学位证书
一比一原版(Concordia毕业证书)康卡迪亚大学毕业证成绩单学位证书一比一原版(Concordia毕业证书)康卡迪亚大学毕业证成绩单学位证书
一比一原版(Concordia毕业证书)康卡迪亚大学毕业证成绩单学位证书
atedyxc
 
一比一原版(UPenn毕业证书)宾夕法尼亚大学毕业证成绩单学位证书
一比一原版(UPenn毕业证书)宾夕法尼亚大学毕业证成绩单学位证书一比一原版(UPenn毕业证书)宾夕法尼亚大学毕业证成绩单学位证书
一比一原版(UPenn毕业证书)宾夕法尼亚大学毕业证成绩单学位证书
atedyxc
 
一比一原版(Cornell毕业证书)康奈尔大学毕业证成绩单学位证书
一比一原版(Cornell毕业证书)康奈尔大学毕业证成绩单学位证书一比一原版(Cornell毕业证书)康奈尔大学毕业证成绩单学位证书
一比一原版(Cornell毕业证书)康奈尔大学毕业证成绩单学位证书
atedyxc
 
一比一原版(SFU毕业证书)西蒙菲莎大学毕业证成绩单学位证书
一比一原版(SFU毕业证书)西蒙菲莎大学毕业证成绩单学位证书一比一原版(SFU毕业证书)西蒙菲莎大学毕业证成绩单学位证书
一比一原版(SFU毕业证书)西蒙菲莎大学毕业证成绩单学位证书
atedyxc
 

Recently uploaded (20)

一比一原版(Caltech毕业证书)加州理工学院毕业证成绩单学位证书
一比一原版(Caltech毕业证书)加州理工学院毕业证成绩单学位证书一比一原版(Caltech毕业证书)加州理工学院毕业证成绩单学位证书
一比一原版(Caltech毕业证书)加州理工学院毕业证成绩单学位证书
 
How to exchange my pi coins on HTX in 2024
How to exchange my pi coins on HTX in 2024How to exchange my pi coins on HTX in 2024
How to exchange my pi coins on HTX in 2024
 
一比一原版(ASU毕业证书)亚利桑那州立大学毕业证成绩单学位证书
一比一原版(ASU毕业证书)亚利桑那州立大学毕业证成绩单学位证书一比一原版(ASU毕业证书)亚利桑那州立大学毕业证成绩单学位证书
一比一原版(ASU毕业证书)亚利桑那州立大学毕业证成绩单学位证书
 
Economic Risk Factor Update: May 2024 [SlideShare]
Economic Risk Factor Update: May 2024 [SlideShare]Economic Risk Factor Update: May 2024 [SlideShare]
Economic Risk Factor Update: May 2024 [SlideShare]
 
一比一原版(UCSB毕业证书)圣塔芭芭拉社区大学毕业证成绩单学位证书
一比一原版(UCSB毕业证书)圣塔芭芭拉社区大学毕业证成绩单学位证书一比一原版(UCSB毕业证书)圣塔芭芭拉社区大学毕业证成绩单学位证书
一比一原版(UCSB毕业证书)圣塔芭芭拉社区大学毕业证成绩单学位证书
 
Maximize Your Business Potential with Falcon Invoice Discounting
Maximize Your Business Potential with Falcon Invoice DiscountingMaximize Your Business Potential with Falcon Invoice Discounting
Maximize Your Business Potential with Falcon Invoice Discounting
 
Bond Bazaar Powerpoint Presentation in Details
Bond Bazaar Powerpoint Presentation in DetailsBond Bazaar Powerpoint Presentation in Details
Bond Bazaar Powerpoint Presentation in Details
 
一比一原版(UC Davis毕业证书)加州大学戴维斯分校毕业证成绩单学位证书
一比一原版(UC Davis毕业证书)加州大学戴维斯分校毕业证成绩单学位证书一比一原版(UC Davis毕业证书)加州大学戴维斯分校毕业证成绩单学位证书
一比一原版(UC Davis毕业证书)加州大学戴维斯分校毕业证成绩单学位证书
 
Bahawalpur Culture.pptx pptx pptx pttx pttx
Bahawalpur Culture.pptx pptx pptx pttx pttxBahawalpur Culture.pptx pptx pptx pttx pttx
Bahawalpur Culture.pptx pptx pptx pttx pttx
 
Diversification in Investment Portfolio.pdf
Diversification in Investment Portfolio.pdfDiversification in Investment Portfolio.pdf
Diversification in Investment Portfolio.pdf
 
NO1 Popular Black Magic Specialist Expert Amil baba in Norway Poland Portugal...
NO1 Popular Black Magic Specialist Expert Amil baba in Norway Poland Portugal...NO1 Popular Black Magic Specialist Expert Amil baba in Norway Poland Portugal...
NO1 Popular Black Magic Specialist Expert Amil baba in Norway Poland Portugal...
 
What exchange can I sell my pi coins in 2024
What exchange can I sell my pi coins in 2024What exchange can I sell my pi coins in 2024
What exchange can I sell my pi coins in 2024
 
DSP Gold ETF Fund of Fund PPT - April'2024
DSP Gold ETF Fund of Fund PPT - April'2024DSP Gold ETF Fund of Fund PPT - April'2024
DSP Gold ETF Fund of Fund PPT - April'2024
 
一比一原版(Concordia毕业证书)康卡迪亚大学毕业证成绩单学位证书
一比一原版(Concordia毕业证书)康卡迪亚大学毕业证成绩单学位证书一比一原版(Concordia毕业证书)康卡迪亚大学毕业证成绩单学位证书
一比一原版(Concordia毕业证书)康卡迪亚大学毕业证成绩单学位证书
 
一比一原版(UPenn毕业证书)宾夕法尼亚大学毕业证成绩单学位证书
一比一原版(UPenn毕业证书)宾夕法尼亚大学毕业证成绩单学位证书一比一原版(UPenn毕业证书)宾夕法尼亚大学毕业证成绩单学位证书
一比一原版(UPenn毕业证书)宾夕法尼亚大学毕业证成绩单学位证书
 
project ratio analysis of bcom studies .
project ratio analysis of bcom studies .project ratio analysis of bcom studies .
project ratio analysis of bcom studies .
 
一比一原版(Cornell毕业证书)康奈尔大学毕业证成绩单学位证书
一比一原版(Cornell毕业证书)康奈尔大学毕业证成绩单学位证书一比一原版(Cornell毕业证书)康奈尔大学毕业证成绩单学位证书
一比一原版(Cornell毕业证书)康奈尔大学毕业证成绩单学位证书
 
1. Elemental Economics - Introduction to mining
1. Elemental Economics - Introduction to mining1. Elemental Economics - Introduction to mining
1. Elemental Economics - Introduction to mining
 
一比一原版(SFU毕业证书)西蒙菲莎大学毕业证成绩单学位证书
一比一原版(SFU毕业证书)西蒙菲莎大学毕业证成绩单学位证书一比一原版(SFU毕业证书)西蒙菲莎大学毕业证成绩单学位证书
一比一原版(SFU毕业证书)西蒙菲莎大学毕业证成绩单学位证书
 
20240514-Calibre-Q1-2024-Conference-Call-Presentation.pdf
20240514-Calibre-Q1-2024-Conference-Call-Presentation.pdf20240514-Calibre-Q1-2024-Conference-Call-Presentation.pdf
20240514-Calibre-Q1-2024-Conference-Call-Presentation.pdf
 

BIO420 Chapter 24

  • 2. Developmental Plasticity • The Environment plays as much a role in development as our genes • Phenotypic plasticity is when an organism can react to the environment by changing its state, form, or activity • Developmental plasticity is when this occurs in the larval stage • a good example of this is metamorphosis- the same genes are present in the adult and larvae, but you find different manifestations in phenotype
  • 3. Types of Phenotypic Plasticity • The are two main types • Reaction Norm- the genome has a continuum of phenotypes, and the environment will determine which will form • Think of muscle growth when one works out. • Polyphenism- This is an on/off or an either/or situation. It is not on a continuum. There are various types such as: • Diet-induced • Methylation • Predator induced
  • 4. Diet-Induced Polyphenism • The caterpillar Nemoria arizonaria will look like a twig or an oak flower depending on what it eats. • The flowers are seasonal, so it doesn’t want to look like a flower when there are no other flowers out • This depends on eating young leaves • If older leaves are eaten, the caterpillar will look, instead, like a twig • Honey bees feed a royal jelly containing royalactin to bees destined to become queen. • Royalactin stimulated egg production in the queen
  • 5.
  • 6. continued • Dung beetle larvae eat food left by the mother • The quality and the quantity of the food left in a particular hole determines the amount of juvenile hormone made in the last molt • This determine the presence of horns or not • Recall that methyl groups can be added to segments of DNA. In general, it will repress transcription of the gene • This will cause changes in the phenotype • Some supplements (like folic acid) are methyl donors
  • 7. Predator-Induced Polyphenisms • When water fleas detect chemicals from predatory fly larvae, they alter their development • They will make spiked heads and tails which make them difficult to swallow
  • 8. Predator-Induced Polyphenisms • When embryos of the Costa Rican Red-Eyed tree frog sense vibrations from a snake crawling on a leaf, the eggs prematurely open and the larvae fall to the water below
  • 9. Temperature as an Environmental Agent • In some species, the decision on the development of testes or ovaries depend on temperature • For example, for crocodiles, extreme temperatures will produce females whereas moderate temperatures produce males • In the Malawian butterfly Bicyclus anynana, there is a dry season morph in which the butterfly camouflages in dead leaves on the forest floor • The wet season morph has eyespots on their wings and tend to fly more • This decision is made in the pupal stage
  • 10.
  • 11. Larval Settlement One type of cue is a biofilm. These are often sheeting of bacteria This may be why barnacles form on the hull of boats for example Some marine larvae can suspend development until they experience a particular environmental cue. This is called larval settlement
  • 12. Stress as an Agent • The Spadefoot Toad will change their development according to an environmental stress • This depends on the water levels in the ponds • Tadpoles will go through metamorphosis at different times based on the available water in the pond • When the water levels in the pond drop, the tadpoles sense it and develop a wider mouth and stronger jaws • They become carnivorous (cannibalistic) and morph very quickly
  • 13.
  • 14. Developmental Symbiosis A symbiotic relationship is where an organism comes to depend on another • Usually, the host the larger of the two • The symbiont is the smaller of the two There are two types: • In parasitism, the symbiont benefits at a cost to the host • In mutualism, both the symbiont and host benefit from the relationship
  • 15. Endosymbiosis • In Endosymbiosis, the symbiont will live in (or partly in) the host. There are two typical examples of this in plants: • Nitrogen-Fixing bacteria live in the roots of many plants (you can find particular high amounts in legumes • These bacteria ‘fix’ nitrogen in the air by reducing its triple covalent bond to a single bond compound so the plant can use it. • The bacteria, in turn take sugar from the plant
  • 16. Endosymbiosis • Mycorrhizae fungi are associated with most plant roots (although there are different species of fungi associated with different plants • These fungi increase the area in which the plant can obtain water at the roots • In turn, the fungi consume sugar from the plant.
  • 17. Mechanisms of Developmental Symbiosis Vertical Transmission is the transfer of symbionts from one generation to the next • Some symbiosis is obligate mutualism- meaning that they can not survive without each other. • An example of this can be found in lichens (a symbiotic relationship between fungi and algae) Horizontal Transmission is when one becomes infected by other members of the species • Humans acquire some symbionts as they travel through the birth canal. Others can be transmitted through contact with the skin during breast feeding
  • 18. Developmental Symbiosis in the Mammal Intestine In mice, bacteria help with cell differentiation. The gut bacteria up-regulate transcription of many genes Studies in mice show that without intestinal bacteria, villi (the absorptive part of the intestine) will not be vascularized and there will be no brush border enzymes Gut bacteria is also important for mammalian gastric- associated lymphatic tissue Bacteria may be involved in things like brain formation and reproduction.
  • 19. Developmental Symbiosis in the Mammal Intestine Mammals have co-evolved with bacteria to the point that our body phenotypes do not develop without them There are more bacteria in humans than we have cells in our body There are around 400 species of gut bacteria in us We are only beginning to understand how they interact with us