unit 8 t1-2

Ethology

The study of how evolutionary processes shape inherited behaviours and the ways that animals respond to specific stimuli

Behaviour

An animal’s response to a stimulus (internal or extrernal)

• Nature vs nurture (environmental factors vs genetics)

Proximate cause

How a behaviour occurs or how it is modified

• What was the stimulus to cause this behaviour?

• How does the “nurture” component affect behaviour?

Innate behvaiours

Developmentally fixed, born behaviours that do not need to be learned (instinctive)

Learned behaviours

Behaviours shaped by experiences

Ultimate cause

Why a behaviour occurs (in context of natural selection)

• How does a behaviour help the animal survive and reproduce

• How does the “nurture” component affect behaviour? (What is the evolutionary basis of the behaviour)

Fixed action pattern

A sequence of unlearned acts directly linked to a stimulus

• Actions are unchangeable

• Carried out to completion

• Triggered by a sign stimulus (external cue)

Stimulus response chain

Directed movements

Movements towards or away from a stimulus

(Some reason sayin the same thing as taxis)

Biological clock

Internal mechanisms that regulate the timing of physiological processes and behaviours in response to environmental cues; can sustain biological rhythms independently

Circadian rhythm

(Biological clock)

Internal rhythm that follows a roughly 24hr cycle that regulates activities (sleep, feeding, hormone release)

• Diurnal: most active during the day

• Nocturnal: most active during night

• Crepuscular: most active at dawn or dusk

Sign stimulus

Migration

A regular long distance change in location triggered by suns position, earths magnetic field, celestial cues

Kinesis

A change in the rate of movements or the frequency of turning movements in response to a stimulus; non-directional

(Faster more frequent movements during day vs night)

Taxis

Directional movements towards (+) or away from (-) a stimulus

Phototaxis

Type of taxis

Movement is response to light

Chemotaxis

Type of taxis

Movement in response to chemical signals

Geotaxis

Type of taxis

Movement in response to gravity

Imprinting

Long lasting behavioural response to an individual (forming an exclusive attachment to)

• occurs during a sensitive/critical period early in life

Spatial learning

Establishing memories based upon the spatial structure of the animals surroundings

• Some animals form a cognitive map or use landmarks as environmental cues

Cognitive map

Mental image/model an individual uses to remember or navigate an area

Associative learning

Ability to associate one environmental feature with another

• Connecting one thing to another, touching fire = pain, drawing the connection to not do it

• Changing behaviour due to the learned associated response (dogs doing tricks = treats, peanuts = allergy

Social learning

Learning through observations and imitations of the observed behaviours

Altruism

Selfless behaviour where an individual acts in a way that benefits others and not itself

Reduces own fitness but increases rest of the population

Phototropism

Directional response that allows plants to grow towards (some cases away) a source of light

Photoperiodism

Allow plants to develop in response to day length; plants flower at certain times of the year

• soil composition can affect plants

• pH of soil can change flower colouring in some plants, nutrients are more accessible in certain pH

Physical defenses

In plants they have defences like thorns, trichomes (small plant like hairs)

In animals it is traits like horns, teeth, claws, quills, shells…

Chemical defences

In plants they can produce toxic or distasteful compounds, smelling bad…

In animals they can produce venom or toxins, odours, slime…

Metabolic rate

The total amount of energy an animal uses in a unit of time

• can be measured in calories, heat loss or by the amount of oxygen consumed (or CO2 produced)

Smaller organisms = higher rate

Larger organisms = lower

Ecosystem

The sum of all the organisms living in a given area and the abiotic factors they interact with

Biotic

Refers to anything that is or was living within an environment

Abiotic

Refers to anything non-living within an environment

• earth is the only biosphere because it has all the abiotic factors that can support life

Laws of thermodynamics

1: energy is neither created nor destroyed, only transferred

• law of conservation of mass: chemical elements are continually recycled in the environment

2: exchanges of energy increase the entropy of the universe (entropy is a measure of disorder)

• net gain of energy results in energy storage or growth of an organism

• Net loss of energy results in the loss of mass and eventual death

Communication

To survive and reproduce, organisms must be able to detect to and respond to information

A stimulus is generated and transmitted from one individual to another

• subject to natural selection

Mode of communication

Visual: behaviours or physical traits that can be seen

• Colouration

• Threat displays

• Bird courtship: dancing or posing

• Establishing territories: markings, structures

Auditory: sounds made

• Mating calls

• Warning calls

• Establishing territories: male birds singing songs to announce

Tactile: through touch/physical contact

• Grooming: primates groom each other to bond

• Dances

Electrical: use of electrical fields generated by specialized cells

• Hunting: sharks, rays and other electric fish send electrical signals through the water to locate prey

Chemical: pheromones emitted by a member of a species that can affect other members of the same species

• some cause rapid change in behaviour while others cause long term changes

• Foraging: ants following pheromone trail to food

• Marking: some animals mark territory with scent

• Warnings: alarm pheromones

• Dominance: queen bees are covered in cuticular hydrocarbons that function pheromones to inform their rank in hive

Sexual selection

Mating and reproduction

Type of natural selection for successful mating that results in the reproductive advantage of some individuals over others of the same species/sex

• Remember fitness is measured by the reproductive success that favour behaviours (innate or learned) that increase survival and reproduction

Mating behaviours

Mating and reproduction

Animals can by monogamous or polygamous

When selecting mates there are factors like competition (males compete for females) and courtship rituals that help ensure that the m/f are the same species and provides females an opportunity to evaluate mates and/signal for nest building and ovulation

Cooperation

Many animals benefit by forming groups (pack of wolves, pride of lions, herds…)

Cooperative behaviours are behaviours that benefits the group

Endotherm

Uses thermal energy from metabolism to maintain body temperature

• Can regulate their own body temp internally

Ectotherm

Uses external sources like sun/shade to regulate their body temperature

Ecological levels

Species

Population

Community

Ecosystem

Biome

Biosphere

Special People Cant Enter Big Buildings

Primary producer

Autotrophs who use light energy to synthesize organic compounds

Photosynthesis = Light energy + CO2 + H2O → O2 + C6H12O6

Heterotrophs

Rely on autotrophs because they cannot make their own food

• Gets energy from other organisms

Primary consumer (1º)

Herbivores that eat the primary producer

Secondary consumer

Carnivores (including omnivores but “carnivores” is used to be more simple) that eat herbivores (1º)

Tertiary consumer

Carnivores that eat other carnivores (2º, secondary consumers)

Quaternary consumer

Carnivores that eat tertiary consumer (if they have no natural predators they are the apex predator)

Decomposer

Small organisms (like bacteria and fungi) that get energy from detritus (non-living organic material; leaves, wood, dead organisms) produced at other trophic levels

• important for recycling chemical elements

Scavenger

Animals that consume dead/decaying organisms (plants or animals)

Biochemical cycles

Nutrient cycles that contain both biotic and abiotic factors

• Water, carbon, nitrogen and phosphorous cycle

Primary production

The amount of light energy that is converted to chemical energy

• Primary producers set a “spending limit” for the entire ecosystems energy budget

GPP

Gross Primary Production, the total primary production in an ecosystem

NPP

The GPP minus the energy used by the primary producers for respiration (Ra)

Secondary production

The amount of chemical energy in a consumer’s food that is converted to new biomass

• The transfer of energy between trophic levels is at around 10% efficiency

Water cycle

Water is essential for all life and influences the rate of the ecosystem processes

Carbon cycle

Carbon is essential for life and required in the formation of organic compounds

Nitrogen cycle

Nitrogen is important for the formation of amino acids, proteins and nucleic acids

Phosphorus

Phosphorus is important for the formation of nucleic acids, phospholipids and ATP