• Since there is a large concentration of Na+ outside the cell, Na+ rushes in making the intracellular fluid less negatively charged
•  This causes the peak of the action potential 

• Voltage gated K+ channels also open

• But they are much slower than Na+ channels
•  They are fully open after the peak of the action potential
• K+ flows out of the cell, and the membrane potential becomes negative again 

• myelinated

1.  Depolarization at the synaptic terminal results in Ca++ influx
2.   Ca++ causes vesicles containing neurotransmitter to fuse with presynaptic membrane
3.   Neurotransmitter diffuses into synaptic cleft
4. Neurotransmitter binds to ion channels on the post synaptic membrane (This is the case for cholinergic synapse) 

0. 2 subthreshold signals from a single presynaptic cell can sum together if signals are within milliseconds of each other and generate a threshold stimulus. 1 stimulatory and 1 inhibitory signal can cancel each other if they are simultaneous. 

excitatory to vertebrate skeletal muscle; other effects at other sites 

• Parkinson’s Disease, Schizophrenia, reward center of brain, social power stimulates it 

0. GABA, glycine (savory to taste receptors), glutamate (excitatory, stimulates taste receptors), aspartate 

How does an SSRI ( Selective serotonin reuptake inhibitor) or a monoamine oxidase inhibitor work to increase serotonin availability? 

SSRI blocks the uptake of serotonin back into the presynaptic cell after signal. This makes serotonin signal last longer in the synaptic cleft. Monoamine oxidase inhibitor prevents mitochondria from breaking down serotonin in the synaptic terminal, making more serotonin available. 

environmental stimuli that trigger behavior, e.g., day length, visual stimuli

why does stimulus trigger behavior - generally believed to be due to natural selection (adaptive behavior) 

An animal may not exhibit a possible behavior in certain environments 

Lorenz theorized that certain "infantile features"—like big heads, large eyes, button noses, and round bodies—trigger a nurturing response in adults Evolutionarily, this makes us more likely to care for our offspring, but our preference for cuteness is so strong it spills over to other species. 

Genetic component - illustrated by intermediate strips and tucking behavior in hybrid
Environmental component - illustrated by loss of ineffective tucking behavior by hybrids in later seasons. 

certain traits (such as lizard pushups) are found in evolutionary related groups and are believed to evolve just like traits such as body shape. 

Sequence of behavioral acts that is unchangeable and usually carried to completion once initiated

many animals only use a relatively small subset of sensory information to trigger behavior, humans are more complex

Fixed action pattern is cueing on visual landmarks to locate nest

sign stimulus is pattern of landmarks around nest 

Fixed action pattern = aggression twards other “males” sign stimulus = red belly
More complex fixed action patterns in courtship behavior 

A type of learning that is limited to a sensitive period of an animals life and is generally irreversible
Work of Konrad Lorenz (nobel prize 1973) 

Bonding occurs after hatching
imprint of “mother”
important for eliciting care, developing species identity

during sensitive period can be experimentally imprinted on the wrong mother. 

recorded growls from 20 pet dogs in three different situations: a tug-of-war game with their owner, competing with another dog for a bone and growling at an approaching stranger.
played the recordings to 36 other dogs that had each been left to gnaw on a bone. Only those that heard the food-guarding growls tended to back off from the bone and stay away.
It seems that dog growls communicate context 

Vocabulary of 150 words
names of 50 objects- could describe their colors, shapes and the materials they

were made from.
He could ask for things—and would reject a proffered item and ask again if it was not what he wanted.

He understood, and could discuss, the concepts of “bigger”, “smaller”, “same” and “different”.
He could count up to six, including the number zero (and was grappling with the concept of “seven” when he died). 

the scientific study of the interactions between organisms and the environment

distribution of organisms and their abundance Ecology reveals the richness of the biosphere 

Ecologists work at levels ranging from individual organisms to the planet 

how an organism’s structure, physiology, and (for animals) behavior meet environmental challenges 

Large size – N. American record 175 pounds Bite strength 2X german shepard

Behavioral adaptations may be most unique aspect – Largest N. American carnivore that hunts in groups
Wolf cooperation 

focuses on factors affecting how many individuals of a species live in an area 

The human population increased relatively slowly until about 1650 and then began to grow exponentially 

Exponential population growth is population increase under idealized conditions
Under these conditions, the rate of reproduction is at its maximum, called the intrinsic rate of increase
Concept 53.4: The logistic model describes how a population grows more slowly as it nears its carrying capacity
Exponential growth cannot be sustained for long in any population 

maximum population size the environment can support 

the whole array of interacting species in a community 

Spartina grass communities (invasive species)
This type of community not native to the Pacific Northwest, but started to appear in the Puget Sound area in the 1990’s
East coast has spartina estuaries that are different the Pacific NW

Pacific NW estuaries normally mudflat and eelgrass community
Spartina grass – unlike native WA plants can live on mudflats and submerged sediments due to physiological capability
Willapa Bay was being overrun by Spartina alterniflora

Thousands of acres affected 

the community of organisms in an area and the physical factors with which they interact

energy flow and chemical cycling among the various biotic and abiotic components 

Increased source from atmosphere from fertilizer ammonia and other human activities.

Negative ecological impacts of N deposition – Adds nitrogen to alpine

communities that normally have low nitrogen levels 

High biomass and density
Similar to tropical rainforest
Endemic species specialized for vent life Seafloor away from vents – low biomass 

Many vent animals are chemoautotrophic symbioses
Hydrogen sulfide (chemical energy) rather than sunlight is a major source of energy for this system
An adaptation to exploit sulfide-rich environments
Mutualism with symbionts satisfies much or all of the host’s nutritional needs 

Inflation of the volcano (rise of seafloor) is being measured and it seems to be inflating to the point where previous eruptions have resulted 

arrays of ecosystems and how they are arranged in a geographic region 

the global ecosystem, the sum of all the planet’s ecosystems

the influence of energy and materials on organisms across the biosphere