BIO 111 intro to ecology/behavioral ecology

interactions among organisms and between them and their environment

Ecology studies what?

organism, population, community, ecosystem

what levels can ecology be studied at

organismal ecology

study of the ways in which individual organisms meet challenges of their environments, both biotic and abiotic

physiological ecology

how organisms are physiologically adapted to their environment and how environment impacts species distribution

behavioral ecology

how individual behavior contributes to survival and reproductive success

population ecology

- focuses on groups of interbreeding individuals of ONE species

- goal to understand factors affecting population,growth, density, and size

- invasive species have huge effect on some populations

community ecology

- studies how populations of species interact and form functional communities

- focuses on why some areas are species rich while others are species-poor

- also studies succession (how species composition and community structure change over time)

ecosystem ecology

The study of energy flow and the cycling of chemicals among the various biotic and abiotic components in an ecosystem.

- levels in food chains are called trophic levels

- food chains may interconnect forming food webs

discovery approach

Ecologists make verifiable observations

hypothesis driven

ecology science may be conducted in the field or in the lab

hypothesis: larval parasitic blowflies have a significant effect on the reproductive success (offspring) of small birds.

example of hypothesis driven ecological research:

•Sylvie Hurtrez-Boussès and colleagues studied whether parasites have a meaningful impact on baby birds

•Parasites are found on nearly all species at some point.

what is the hypothesis

◦Moths native to Europe, larvae feed on buds

◦Emergence coincides with bud opening, if their tree is bare, they can 'balloon' to a new one

◦Were introduced to apple orchards in N. America where they became a pest.

◦Before figuring out how to fight them, needed to understand their biology

discovery approach example:

Temperature

◦Biggest effect, freeze ruptures cells, high heat disrupts metabolism, fire- deadly or necessary

Wind

◦Affects heat and water loss, wave action

Water

◦Limits plant distribution, that limits animals

examples of physiological ecology (abiotic factors)

Have huge impacts on the distribution of organisms

- light: shading and photic zone

- salinity: affects osmoregulation

- pH: low pH limits nutrient availability in soil, causes fish decline

examples of abiotic factors

Most organisms exist within limited ranges of abiotic factors

abiotic factors limit range how?

Climate is the prevailing weather pattern of a region affected by temperature, light, wind, and precipitation

◦Not 'in the moment' weather

Latitude affects intensity of sunlight, which increases temperature, which affects atmospheric circulation

climate affects range how?

adiabatic cooling

increasing elevation leads to a decrease in air pressure, causing a 10° Celsius drop for ever 1,000 meter

rain shadow

warm, moist air flows up mountain and cools, releasing precipitation; leeward side allows drier air to descend, forming area of low precipitation

biome (differences in climate define terrestrial biomes)

type of ecological community

6 aquatic biomes

Distinguished by differences in

◦Salinity

◦Oxygen content

◦Depth

◦Current strength

Availability of light

Freshwater habitats divided into lentic (standing water) and lotic (running water) habitats

aquatic biomes

behavioral ecology

Study of how behavior contributes to differential survival and reproduction

Behavior is the observable responses of organisms to external or internal stimuli

◦Some genetic and some learned

genetics and learning

Some behaviors are genetically programmed, referred to as innate, based on genes

Most individuals will exhibit the same behavior regardless of environment

fixed action patterns

Example: Egg-rolling response in geese

◦Once initiated, will continue until completed

sign stimulus

for geese, sign stimulus is an egg out of the nest

initiates behavior

Learning

modification of behavior based on previous experience

habituation (organism ignores repeated stimulus)

simplest form of learning

associative learning

behavior is changed or conditioned though association between a stimulus and response

classical conditioning

involuntary response

operant conditioning

trial and error

cognitive learning

solving problems with conscious thought

Chimps, ravens

Behavior is often a mix of innate and learned components

◦Example: Birds are genetically programmed to learn songs, but they will sing the correct song only if the correct songs are heard

Innate behavior interacts with learning

critical period

process is called imprinting

-Example: goslings follow the first moving thing as "mother"

period of development during which animals develop irreversible species-specific patterns of behavior

migration.

-◦Experienced birds can correct for displacement (a complex navigational skill), while young, inexperienced birds cannot

innate behavior interacts with learning during _______

◦Migration

◦Foraging

◦Communication

◦Group behaviors

Altruism

◦Mating systems

common behaviors studied in behavioral ecology include

migration

Usually linked to food availability, can be very long trip

◦Piloting- using familiar landmarks

◦Orientation- using compass bearings

Some birds can detect magnetic fields from the poles

◦Navigation- use compass bearings and can make adjustments

How do migrating animals find their way?

foraging

-◦Moving can be dangerous, organisms try to optimize energy gained vs lost

Whether to try to take down large prey or small (lots of food, but tough to tackle)

Defending territory

whether to stay in one place or look for food elsewhere

territory

Animals tend to optimize territory size based on costs and benefits

◦Cost of defending < rewards of what's inside

Fixed area in which individual or group excludes others, using aggression or territory marking

communication

-Different forms in different environments

◦Sound more important in dense forest

◦Visual more important in open prairie

◦Long lasting scent used for marking territory

◦Social insects lay down scent trails

◦Sound for urgent messages

For many different purposes

◦Mate attraction, defending territory, contacting offspring, avoiding predators

tactile communications

-Example: Grooming in primates

Example: Round dance or waggle dance of the honeybee scout

Can be used to establish bonds between group members

Used by many insects to convey information on location of food

group behavior :

benefits:

◦Increased vigilance

◦Lowered odds of being caught

◦Assistance rearing young

◦Locating food

Group living can increase food competition and risk of disease transmission, but has many benefits......

altruism

Behavior that benefits others at a cost to yourself

kin selection

◦Actions may lower your own fitness, but help a relative

coefficient of relatedness, r

- A mother and father are on average related to children by r = 0.5

probability that any two individuals will share a copy of a particular gene

altruistic gene is favored by natural selection when (rB>C)

r=coefficient of relatedness of donor to recipient

b=benefit to recipient

c=cost incurred by donor

hamiltons rule

Promiscuity, monogamy, polygamy, polyandry

mating systems

promiscuity

maximizes genetic diversity

monogamy

may help rearing dependent offspring, prevent infidelity

◦Usually not sexually dimorphic

polygyny

usually have uniparental care

-sexually dimorphic

-dominant male may guard resource or females

polyandry

rarer, females larger than males

◦Resources not limiting, egg production