Thursday, October 30, 2014

Memory & Amnesia

(This post has resources and information for learning about Memory and Amnesia, for Physiological Psychology.)

Radio Lab:

6:30 Rat tests, 8:08 Chemical prevent memory in rats;  Clive Waring 42:30

 The Hippocampus and Patient H.M.(by Ted Ed)

H.M. - Nova special

 9:22 What like for H.M.  10:40-11:52 Muscle memory star test

Morris Water Maze

Friday, October 24, 2014

Periodic Table of Cookies

In honor of chemistry week,
Here's the Periodic Table of Cookies my club (Science Association of Women at UVU) did this spring to make money.  Making that many cookies was insane.  But fun. :)

Printed on sugar overlay, we cut each square out

Tuesday, October 21, 2014

Footprints and trackways

How do paleontologists and anthropologists use footprints and trackways?  Often, information is extrapolated from tracks and used to determine approximate heights and sizes of the organism that left the tracks.  How can this be?  Is there a correlation between foot size, leg length, stride length...and HEIGHT?  Let's find out!

These formulae don't only work for dinosaurs. If you like Lego, you may like to know that using Alexander and Thulborn's formulae, a Lego minifig (the little people) could walk at 0.5 km/h and run at 2.2 km/h
Lego minifigs running and walking
Using the same equations that estimate dinosaurs' speeds, Lego figures could run at 2 km/h and walk at 0.5
(Lego info from

Speed (in metres per second)=0.25 x (square root of g) x [stride length]^1.67 x [hip height]^-1.17

Where g is the acceleration from gravity. On Earth, g=9.8 m/s². Don't worry if you haven't come across maths like this before. What's important is that it's a way of estimating an animal's speed, without measuring it directly.
We can check Alexander's formula by comparing it to our measurements. The stride length is just the distance (100m) divided by the number of strides (half the number of steps). In terms of your measurements, Alexander's formula becomes:
Speed (in metres per second)=7.8 x ( 200/[number of steps] )^1.67 x [hip height]^-1.17
Your actual speed is just the distance divided by the time it took:


The basic measurement of a dinosaur footprint is its length, represented as FL. The ratio of footprint length and hip height (h) is different for different groups of dinosaurs, but generally the hip height of a bipedal dinosaur is roughly four times the footprint length. The speed can then be determined as relative speed, which is stride length (SL), divided by hip height (h). Generally speaking, if the SL/h <2.0, then the animal was walking; >2.9, the animal was running; and between 2.0 and 2.9, the animal was trotting.1  (Source:

What can a single track tell us?

Not too much. We can infer something about the size of the animal and maybe something about the sediment. We may have a clue as to who made the track.

What can a trackway (a series of tracks or footprints) tell you?

  • Who was there.
  • How many animals were there.
  • The sizes of the animals compared to one another.
  • How they were interacting - social activity, such as herds, moving in families, etc.
  • How fast they were moving.
  • What the sediment was like, and therefore something about the environment of the time.

    Source of above text:

Thursday, October 2, 2014

Leaf Anatomy

View of a shoot apical meristem with some leaf primordia.  Additionally, I have labelled the 3 primary meristems you can differentiate here.

Here's a nicotine leaf to show the two kinds of meristems specific to the leaf.  The leaf apical meristem becomes the midrib of the leaf, while the leaf marginal meristem is the blade of the leaf.

From a Sedum (stone crop)- you can see the "regular" epidermal cells (squiggly shaped) as well as the guard cells in various places surrounding stomata.

 Take a closer look:

Also here is a sunken stomate as seen in a Pinus leaf.  It is "sunken" because the guard cells are below the level of the epidermis which helps protect against dessication (drying out).

Mesophyll just means middle of the leaf.  It is the term for the ground tissue in the leaf.  There are two types by shape: palisade and spongy.
You can see both of these well in a pine leaf:

We also term a leaf to be unifacial or bifacial based on the arrangement of the mesophyll.  Bifacial is if there is spongy on one side, and palisade on the other.  Unifacial is either the same type throughout, or it makes a kind of sandwich with the same kinds on either side and something different in the middle.  You can see this type of unifacial in a Dianthus (carnation) leaf:
(The red rod-shaped parts are palisade, the lighter stained area in the middle with a lot of spaces is spongy.)

Pine anatomy
Some things we learned specifically with pine needles (I'm not sure if they also apply to some other plants, sorry) are the resin duct with epithelium, hypodermal sclerenchyma, and transfusion tissue.
Some of these are labeled:

The outermost layer surrounding the resin duct is the epithelium.  Hypodermal sclerenchyma is below ("hypo") the outermost layer of cells or dermis.  These have thick secondary cell walls which add to the strength of a pine needle, as you have probably tested yourself many times when you got poked with one.  In this repeat picture you can see the hypodermal sclerenchyma with the thick red-stained walls, on either side of the sunken stomate.

Bundle Sheaths
Bundle sheaths are different in C3 plants and C4 plants.
Here, in a C3 grass (Poa), you see their regular bundle sheaths:

Closer.  Just looks like a blank set of cells surrounding the vascular bundle.

But in a C4 plant, like this Zea corn, the sheaths have what is referred to as "Kranz anatomy".  Kranz is German for wreath, and you can see they are rather leaf-like in the following examples. There are two orientation pictures, then it zooms in one a single bundle sheath so you can see the Kranz anatomy.

Leaf Abscission Zone
When a plant loses its leaves, it prepares for this by creating an abscission zone so the leaf can easily fall off without damaging any of the other tissue.  Layers of cells secrete suberin (or is it subirin?) for protection (and are called suberized cells), while the next outermost layer of cells is pre-programmed to break easily, as it were.  The weak layer is called the separation layer.

Whew, that's a lot of leaf anatomy!  Stay curious.

P.S. There are no picture source references cause I took all these with my camera (through the microscope in Botany lab) and did the labeling myself.
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