Ecology - Unit 8.1: Responses to the Environment

What is a discrete sensory input?

A specific, external stimulus from an organism's environment that is received by specialized sensory receptors and then processed by the nervous system to trigger a behavioral response.

What is a simple behavior from a sensory input?

A response to a stimulus experienced through the senses.

Ex. Seeing a bright light may cause a person to squint their eyes or turn away from the light.

What is a complex behavior from a sensory input?

A response to a stimulus experienced through a higher level of cognitive processing and adaptation to the environment rather than a simple and automatic reflex.

Ex. Navigating through an unfamiliar, cluttered space. You have to use many different brain functions to engage your self awareness and all of your senses.

Niko Tinbergen’s 1st question

What stimulus elicits the behavior and what psychological mechanisms mediate the response?

Niko Tinbergen’s 2nd question

How does the animal’s experience during growth and development influence the response?

Niko Tinbergen’s 3rd question

How does the behavior aid survival and reproduction?

Niko Tinbergen’s 4th question

What is the behavior’s evolutionary history?

What is behavioral ecology?

The study of the ecological and evolutionary basis for animal behavior. It includes explanations for animal behavior.

What do Tinbergen’s first two questions do?

They question the proximate causation: “how” a behavior occurs or is modified.

What do Tinbergen’s last two questions do?

They question the ultimate causation: “why” a behavior occurs in the context of natural selection.

What behaviors does natural selection favor?

Both innate and learned behaviors that increase survival and reproduction.

What is a fixed action pattern?

A sequence of unlearned, innate behaviors that is unchangeable. Once initiated, it is usually carried to completion. It is triggered by an external cue known as a sign stimulus.

What is taxis?

The motion or orientation of a cell, organism, or part in response to an external stimulus. Taxis can be positive or negative (to/away from a stimulus)

Qualities of taxis: (Movement direction, response type, and goal)

Movement direction - Directly towards or away from stimulus

Response type - Towards or away from a stimulus

Goal - Find favorable conditions or avoid harmful ones.

What is kinesis?

A random, non-directional movement in response to a stimulus.

Qualities of kinesis: (Movement direction, response type, and goal)

Movement direction - Random, not directed

Response type - Change in speed and turning rate

Goal - Explore surroundings

What is migration

A regular, long distance change in location. Its movement can be triggered by environmental cues.

How can animals orient themselves?

• The position of the sun and their circadian clock

• The position of the sun or stars

• Earth’s magnetic field

What is a circadian clock

An internal 24-hour activity rhythm or cycle.

What is a circadian rhythm?

A daily cycle of rest and activity that can affect some animal behavior.

Examples and specific circadian rhythms

• Behaviors such as migration and reproduction are linked to changing seasons or a circannual rhythm.

• Daylight and darkness are common seasonal cues

• Some behaviors are linked to lunar cycles which affect tidal movements

What are two plant responses to external stimuli?

Photoperiodism - Plants ability to use light to track time as they are able to sense the wavelengths of light.

Phototropism - Plants grow towards or even away from light

What is a signal in behavioral ecology?

A behavior that causes a change in another animal’s behavior

What is communication?

The transmission and reception of signals.

What does cooperative behavior do?

IT tends to increase the survival o fthe individual, therefore the survival of the population.

How do organisms communicate?

Using visual, chemical, tactile, and auditory signals.

Visual/chemical ex: Flowering plants use their coloration and fragrances

Auditory ex: Birds use song

The European Honeybees dance language

• Round dance indicates that food is near

• Waggle dance indicates the distance and location to the food.

Fruit flies courtship - A three-step stimulus-response chain

1. A male identifies a female of the same species and orients towards her. (Uses chemical communication as he smells the female’s chemicals in the air ; uses visual communication as he sees bthe female and orients his body towards her)

2. The male alerts the female to his presence (uses tactile communication as he taps the female with a foreleg)

3. The male produces a courtship song to inform the female of his species (uses auditory communication as he extends and vibrates his wing)

If all three steps are successful the female will allow the male to copulate

How to animals communicate through odors

They emit chemical substances called pheromones

• Female moths can attract a male several km away

• Queen bees affect the development of female workers and male drones

• When a minnow or catfish is injured, an alarm substance in the fish’s skin disperses in the water, causing nearby fish ti seek safety

• Dogs and cats marking territories

What is innate behavior?

Behavior that is developmentally (automatically) fixed and does not vary among individuals.

What is learning?

The modification of behavior based on specific experiences

What is imprinting?

The establishment of a long lasting behavioral response to a particular individual. These behaviors are irreversible.

What is the sensitive period?

A limited developmental phase that is the only time when certain behaviors can be learned. These times vary for different species.

What is spatial learning?

The establishment of a memory that reflects the spatial structure of the environment.

What is a cognitive map?

An internal representation of spatial relationships between objects in an animal’s surroundings.

Ex. Niko Tinbergen showed how digger wasps use landmarks to find nest entrances.

What is associative learning?

Animals associate one feature of their environment with another. They learn to link many pairs of features of their environment but not all.

Ex. Blue jays will avoid eating butterflies with orange/black coloration after eating a distasteful monarch butterfly.

How does behavior effect a population?

It enhances survival and reproductive success in a population.

What is foraging?

A behavior essential for survival and reproduction that includes recognizing, capturing, and eating food items.

How does natural selection relate to behavior?

It refines behaviors that enhance the efficiency of feeding; It facors different alleles depending on the density of the population.

What does mating behavior include?

• Seeking or attracting mates

• Choosing among potential mates

• Competing for mates

• Caring for offspring

What do mating relationships do?

They define a number of distinct mating systems. They vary greatly from species to species - in some species there are no strong pair bonds.

What is a monogamous relationship?

A mating relationship where one male mates with one female. Males and females with monogamous mating systems have similar sexual external morphologies.

What is a morphology?

The study of structures.

What is a polygamous relationship?

A mating relationship where an individual of one sex mates iwth several individuals of the other sex. Species with polygamous mating systems are usually sexually dimorphic makes and females have different sexual external morphologies.

What is polygyny?

A polygamous relationship where one male mates with many females. The males are usually more show and larger than the females.

What is polyandry?

A polygamous relationship where one female mates with many males. The females are often more showy than males.

What is certainty of paternity?

The confident knowledge that an organism is one’s definite offspring. It influences parental care and mating patern.

What is the difference between males and females when it comes to certainty of paternity?

Females can be certain that eggs laid or young born contain her genes. Male certainty depends on mating behavior.

What is the paternal certainty with internal fertilization?

It is relatively low because mating and birth are separated over time.

What is the paternal certainty with external fertilization?

It is relatively higher when egg laying and mating occur together.

Parental care in external fertilization

It is at least as likely to be by males as by females.

What is intersexual selection?

A form of sexual selection where members of one sex choose mates on the asis of certain traits. (inter=between)

What is intrasexual selection?

A form of sexual selection that involves competition between members of the same sex for mates. (intra=within)

What is female choice?

A type of intersexual competition where females drive sexual selection by choosing males with specific behaviors or features of anatomy. These ornaments often correlate with health and vitality.

What is male competition?

A source of intrasexual selection that can reduce variation among males. Such competition may involve agonistic behavior.

What is agonistic behavior?

An often ritualized contest that determines which competitor gains access to a resource.

What behaviors do natural selection favor?

Ones that maximize an individual’s survival and reproduction. These behaviors are often selfish.

What is altruism?

The kind of behavior where animals reduce their individual fitness but increase the fitness of others. These behaviors are selfless

What is inclusive fitness?

The total effect an individual has on proliferating its genes by producing offspring and helping close relatives produce offspring. It can explain altruism.

What is Hamilton’s rule?

A rule that mathematically predicts when natural selection would favor altruistic acts among related individuals.

What are the three key variables in an altruistic act?

• Benefit to the recipient (B)

• Cost to the altruistic (C)

• Coefficient of relatedness (the fraction of genes that, on average, are shared (r))

When does natural selection favor altruism?

When rB>C ; As long as the benefit to the recipient and relatedness are greater than the cost, natural selection will favor the act.

What is kin selection?

The natural selection that factors this kind of altruistic behavior by enhancing reproductive success of relatives with no expectation of the favor being returned.