AP Biology Discussion Notes Wednesday 4/29/2015

Goals for the Day Understand how we influence the environment & organisms around us Be able to tie together multiple disciplines in biology

Question of the Day4/29 Is it possible that things that are advantageous in one environment are “maladaptive” or disadvantageous in others? Give an example to explain your answer.

Food Selection – The Research Part III Saito et al, 2005 The DESIGN

Food Selection – The Research Part III Saito et al, 2005 The EXPERIMENT TRICHROMATIC VISION TRICHROMATIC VISION DICHROMATIC VISION DICHROMATIC VISION Photo: KENPEI, J Smith

Food Selection – The Research Part III Saito et al, 2005 The TRAINING Photo: KENPEI

Food Selection – The Research Part III Saito et al, 2005 The TRAINING Photo: KENPEI

Food Selection – The Research Part III Saito et al, 2005 The TEST Photo: KENPEI

Food Selection – The Research Part III Saito et al, 2005 The TEST Photo: KENPEI

Food Selection – The Research Part III Saito et al, 2005 The TEST Photo: KENPEI

Food Selection – The Research Part III Saito et al, 2005 The TEST Photo: KENPEI

Food Selection – The Research Part III Saito et al, 2005 The TEST Photo: KENPEI

Food Selection – The Research Part III Saito et al, 2005 The TEST Photo: KENPEI

Food Selection – The Research Part III Saito et al, 2005 The TEST Photo: KENPEI

Food Selection – The Research Part III Saito et al, 2005 The DESIGN

Food Selection – The Research Part III Saito et al, 2005 The EXPERIMENT TRICHROMATIC VISION TRICHROMATIC VISION DICHROMATIC VISION DICHROMATIC VISION Photo: KENPEI, J Smith

Food Selection – The Research Part III Saito et al, 2005 TRICHROMATIC VISION TRICHROMATIC VISION DICHROMATIC VISION DICHROMATIC VISION

Food Selection – The Research Part III Saito et al, 2005 The RESULTS

Food Selection – Summary Research suggests that trichromatic vision is more likely to be selected for when food is distinguished from non- food by color. Research suggests that dichromatic vision is more likely to be selected for when food is distinguished from non- food by shape.

So why not trichromacy in the “New world”

The Battle of the Paramecia! Competitive Exclusion! Alone, both species do just fine. The increase in population until the reach the limit of their surroundings and level off. When they try to hang out TOGETHER, things change— for ONE of the species, anyway. Which one? Who wins? Any ideas why that might be?

Day 3

The Cell Biology of Color Vision in Monkeys

How Does Color Vision Work? Cell Biology The retina has two types of cells: rod cells and cone cells. There are more rod cells than cone cells. Cone cells are responsible for color vision.

How Does Color Vision Work? Cell Biology

How Does Color Vision Work?

There are three types of cone cells. More accurately, any given cone cell may be using only one of three types of transmembrane opsin proteins.

Three types of Cone Cell Different kinds of opsin proteins embedded in the membrane of cone cells make each kind able to receive different information from the others. Central Dogma of Molecular Biology: DNA  RNA  Protein Genes code for…. Proteins which lead to function!.

Chromatic Vision: Cone Cells Cone cells in the retina of the eye allow light of different wavelengths to be interpreted as color in the brain. The following slides describe how this pathway works. The Cone cell The Brain Color Light Waves

To produce the signal for color vision, retinal must stimulate the opsin protein but this cannot occur while the retinal molecule is in its cis- conformation.

When 11-cis-retinal absorbs a photon (a basic unit of light), it changes from 11-cis-retinal to All-trans-retinal.

All-trans-retinal stimulates the opsin in the membrane of the cone cell.

The cone cell sends a signal to the brain, resulting in vision.

To produce the signal for color vision, retinal must stimulate the opsin protein but this cannot occur while the retinal molecule is in its cis- conformation. When 11-cis-retinal absorbs a photon (a basic unit of light), it changes from 11-cis-retinal to All-trans-retinal. The cone cell sends a signal to the brain, resulting in vision. All-trans-retinal stimulates the opsin in the membrane of the cone cell. Opsin Image modified from Scientific American, April 09 All-trans-retinal 11-cis-retinal Opsin

The Cell Biology of Color Vision in Monkeys A retinal chromophore opsin molecule is activated by a photon of light. This in turn stimulates the opsin protein that tells the cone cell to send a signal to the brain.

The Role of Opsins There are three types of opsins: Short Wave Sensitive (SWS) Medium Wave Sensitive (MWS) Long Wave Sensitive (LWS) An individual possessing only SWS and MWS opsins will have dichromatic vision. An individual possessing SWS, MWS and LWS opsins will have trichromatic vision.

How Does Color Vision Work?

-When cone cells with the MWS opsin protein are stimulated, green color is perceived by the brain. -When cone cells with the LWS opsin protein are stimulated, red color is perceived by the brain. -When cone cells with the SWS opsin protein are stimulated, blue color is perceived by the brain. yellow -When cone cells with the MWS opsin protein are stimulated AND cone cells with the LWS opsin are stimulated, yellow color is perceived by the brain.

How Does Color Vision Work? -When cone cells with the MWS opsin protein are stimulated AND cone cells with the SWS opsin are stimulated, violet color is perceived by the brain. -When cone cells with the SWS opsin protein are stimulated AND cone cells with the LWS opsin are stimulated, cyan color is perceived by the brain. white light -When all cone cells are stimulated in equal proportions, white light is perceived by the brain. different shades -We perceive different shades of light when our different types of cone cells are stimulated in different proportions.

Chromatic Vision: Opsins 3D Visualization What is the building block ( ________mer) of an opsin protein?

Chromatic Vision: Opsins 3D Visualization 2D Visualization The opsin protein is composed of a string of amino acids. Each green dot in the 2D visualization represents one amino acid.

Opsin Structure The LWS opsin differs from the MWS opsin in three significant places in the amino acid sequence: Position 180: alanine to serine Position 277: phenylalanine to tyrosine Position 285: alanine to threonine MWS opsin LWS opsin

Opsin Structure The LWS opsin differs from the MWS opsin in three significant places in the amino acid sequence: Position 180: alanine to serine Position 277: phenylalanine to tyrosine Position 285: alanine to threonine MWS opsin LWS opsin

Opsin Response to Light The responses to light of each opsin protein (S, M and L) in trichromats are shown to the right. Note how similar the curves look for M and L. The L curve is shifted by about 30 nm response maximum to the right (longer wavelength).

Opsin Response to Light A third opsin provides another channel for sending color signals to the brain. Three opsin proteins allow the eye to detect a richer variety of light wavelengths resulting in the ability to distinguish more colors.

The Genetics of Color Vision in Monkeys

The Genetics of Color Vision The section of DNA on a chromosome that codes for an opsin protein is called an opsin gene.

Location of Opsin Genes The gene coding for the SWS opsin protein is located on chromosome #7. The gene coding for the MWS and LWS opsins are located on the X-chromosome.

Evolution of LWS Opsin Gene The LWS gene arose through gene duplication and gene mutation of the MWS gene on the X- chromosome.

Origin of the LWS Opsin Gene The LWS gene arose through gene duplication and gene mutation of the MWS gene on the X- chromosome.

Gene Duplication

Unequal Crossing Over (Meiosis, Prophase 1)

Origin of the LWS Opsin Gene The LWS gene arose through gene duplication and gene mutation of the MWS gene on the X- chromosome.

Origin of the LWS Opsin Gene The LWS gene arose through gene duplication and gene mutation of the MWS gene on the X- chromosome.

The MWS Opsin Gene

1092 Nucleotides

The MWS Opsin Gene 1092 Nucleotides  GTCGTTAGATAG 

MWS Opsin Gene vs. LWS Opsin Gene Each opsin gene is exactly the same length (1092 nucleotides) MWS Opsin Protein vs. LWS Opsin Protein These 1092 nucleotides undergo transcription and translation and result in a protein that is 364 amino acids in length.

MWS Opsin Gene vs. LWS Opsin Gene (mutations at the nucleotide level that result in protein functional changes) G  T T  A G  A Three simple substitution mutations change the properties of the opsin protein. Now, rather than being maximally stimulated at ~534nm, the resulting opsin protein is maximally stimulated at ~564nm.

What difference does this make at the protein level?

Evolution of LWS Opsin Gene The LWS gene arose through gene duplication and gene mutation of the MWS gene on the X- chromosome.

Fact or Fiction? A monkey researcher in South America discovered that some monkey females are trichromatic. 1.Definitely Fact 2.Possibly Fact 3.Possibly Fiction 4.Definitely Fiction

The Case of Trichromatic Females

Genes code for opsin proteins; the opsin proteins facilitate color vision.

Some new world monkey species have two different MWS alleles. If a female is heterozygous for these alleles she can produce three different types of opsin protein. This means that SOME females in SOME new world species are trichromatic. Females that are homozygous for the MWS gene on the x- chromosome are dichromatic.

The Phylogenetics of Color Vision in Monkeys

Biogeography of Global Monkeys Photo: Frans de Waal, M Arunprasaad, D Wright, P Gonnet, L DeVoldor, W Endo

Monkeys of the World

Phylogenetics – Exploring Relationships Among Species

Geology: Plate Tectonics and Drift

HumanChimpanzeeGorillaOrangutanGibbonRhesusMangabeyBaboonMona ColobusLangur Wooly MonkeyMarmosetSakisOwl MonkeySquirrel MonkeyCapuchinSpider Monkey Continents Split 50 Million Years Ago Color Vision Evolves! Gene Duplication and Mutation Rise of Primates 75 Million Years Ago Primates In New/Old World 55 Million Years Ago Old World New World

Ancestral Characteristic An Ancestral Characteristic is a characteristic shared through common ancestry. A characteristic that is thought to have also been present in the common ancestor. In primates for example DICHROMATIC vision would be considered an “ancestral characteristic” while trichromatic vision would be considered a derived characteristic (one not present in the common ancestor of 2 groups)

HumanChimpanzeeGorillaOrangutanGibbonRhesusMangabeyBaboonMona ColobusLangur Wooly MonkeyMarmosetSakisOwl MonkeySquirrel MonkeyCapuchinSpider Monkey Continents Split 50 Million Years Ago Color Vision Evolves! Gene Duplication and Mutation Rise of Primates 75 Million Years Ago Primates In New/Old World 55 Million Years Ago Old World New World

Day 3 Questions

Can you find the bird?

Here’s a hint…

It’s an American Bittern!

Now that you know what you’re looking for, can you find him in this picture?

American Bittern