S2: Biology Exam 4

If we were to study the relationship between mean decibel (loudness) of a bullfrog and reproductive success, what level of analysis would you use?

• Proximate - physiology

• Proximate - ontogeny

• Ultimate - phylogeny

• Ultimate - adaptive significance

Answer: Ultimate - adaptive significance

A behavior that decreaes the fitness of a donor and increases the fitness of a recipient is an example of _?

• Terretorial behavior

• Dominance behavior

• Fixed action pattern

• Alturistic behavior

• None of the above

Answer: Alturistic behavior

Two males aggressively fighting over mating rites to a female is an example of _?

• Intersexual selection

• Interspecies competition

• Intrasexual selection

• Alturistic behavior

• Parasitism

Answer: Intrasexual selection

What mating system is likely exhibited in species where two individuals are required to raise one offspring?

• Polygyny

• Monogamy

• Polyandry

• Promiscuity

Answer: Monogamy

Levels of Analysis: Proximate

• How the behavior happens (individual level)

• Mechanisms that are the reason for behavior

• Physiology

• Ontogeny

Proximate Analysis: Physiology

What happens inside the animal that creates the behavior?

• Ex:) Increased testosterone levels, neural connections

Proximate Analysis: Ontogeny

How does the behavior develop over the animals life?

Ultimate Analysis: Phlogeny

Why did the behavior evolve in related organisms?

Levels of Analysis: Ultimate

• Why the behavior exists (species level or greater)

• Phylogeny

• Adaptive significance

Ultimate Analysis: Adaptive Significance

How does the behavior help the orgaism survive and/or reproduce?

Ethology

• Animal behavior

• Mostly proximate causation

• Often the what and how of behavior

Behavioral Ecology

• How animals use behavior to survive and reproduce

• Mostly ultimate causation

• Often the why of behavior

Alturism

Acting to increase another individual’s lifetime number of offspring at a cost to one’s own reproduction

• Not all helping is alturism

• Possible explanations for helping are…

  • Mutualism, manipualtion, reciprocity, kin selection

Mutualism

• Not alturism

• 2+ individuals work together for mutual benefit

Manipulation

• Coerced “alturism”

• Occurs when recipient manipulates donor into providing the benefit

Reciprocity

• Alturism until it gets paid back

• Mutually beneficial cycle if done correctly

Kin Selection

• Occurs when behavior is favored due to the benefits that it gives relatives

  • Phenotypic “alturism”

  • Genotypic selfishness

• Direct genetic advantage to alturism

• Natural selection will favor amy behavior that increases propagation of individual’s alleles

• Inclusive fitness

Inclusive Fitness

• Considers gene propagation through direct and indirect reproduction

• Inclusive fitness = direct fitness + indrect fitness

• Hamilton’s rule

Direct Fitness

Component of fitness gained by ones own survival and reproduction

Indirect Fitness

Component of fitness gained by aiding survival and reproduction of non-descendant kin

Hamilton’s Rule

Equation: c < rb

• c = cost to donor

• r = relatedness of donor and reciever

• b = benefit to reciever

Associative Learning: Classical Conditioning

• Association of two unrelated stimuli

• Ivan Pavlov

Associative Learning: Operant Conditioning

• Association of a behavior and reward

• B.F Skinner

Signal Modalities of Communication

Communication: Process in which actors use specially designed signals or displays to modify the behavior of reactors

• The type a species uses is shaped by ecological and physiological restraints

The types are…

• Acosutic, visual, chemical, electric, vibrational, tactile

Uses of Communication: Mate Attraction

Definition: Allows information to pass between potential mates, helping individuals find potential mates and decide whom/when to mate

• Reproductive isolation - species specific, prevents individuals of closely reated species from mating with each other

Uses of Communiction: Communication between Species

Food, predators, status and territory

Parental Investment

Unequal parental investment

• Females: Higher investment of energy and time per offspring

• Males: Lower investment of energy and time per offspring

Differing reproductive strategies

• Females: More successful in few offsprings that are high quality

• Males: Produce large amount of offspring rather than having a few high quality ones

Sexual Selection

• Process in which a heritable trait increases or decreases within a population

• Competition for mates

  • Intrasexual selection

  • Intersexual selection

• Leads to evolution of structures used in combat with other males and ornaments used to attract mates

Intrasexual Selection

Interactions within members of one sex

• Typically leads to traits that enable an individual to win competition

Intersexual Selection

Interactions between members of opposite sex (mate choice)

• Can lead to development of exaggerated traits

Sexual Dimorphism

A difference between sexes

• Secondary sexual characteristics

Secondary Sexual Characteristics

Traits that only develop in one sex, typically when they reach maturity, that aids in the ability to obtain a mate

• May include differences between sexes in size, color or structure

Mating Systems: Monogamy

• One male and one female

• Altrical offspring

Altrical Offspring

• They require long-term, extensive care

• It may take more than one individual to provide enough care for survival

Mating Systems: Polygyny

• One male and may females

• Often occurs in species where males aren’t needed or unable to care for offspring

Mating Systems: Polyandry

• One female and many males

• It is relatively rare

Mating Systems: Promiscuity

• Multiple males and females

• Females either care for young alone or with other females

• They may also live in communal groups where everyone can help out

Group Living: Aggregations

Groups of animals that don’t have any kind of physical or social structure

Group Living: Social Groups

• Social organization

• The individuals have relatively stable relationships

Group Living: Colonies

Social and physical structures

Group Living Benefits and Costs

Benefits:

• Increased safety

• Obtaining food

• Easy to find mate

Costs:

• May attract attention of predators

• Increases resource competition

Which best describes a metapopulation?

• Groups of individuals not of the same species that interact within the same environment

• Collection of individual populations of the same species that have limited interaction with each other

• Groups of individuals of the same species that don’t interact, but live in the same environment

• A very small population

Answer: Collection of individual populations of the same species that have limited interaction with each other

If intesive competition forced members of a species to get as far away from other members of the same species as possible in a given habittat, what type of dispersion pattern would you expect to find?

• Clumped

• Random

• Uniform

• None of the above

Answer: Uniform

A key assumption of the exponential model is that:

• Resources are unlimited

• It’s expressed in units of years

• It’s applied to animals and not plants

• Growth rate slows as population gets larger

Answer: Resources are unlimited

As a population grows it starts to run out of resources and the population reaches an upper size limit for the habitat it lives in; the is termed the _?

• Finite rate of increase

• Equilibrium point

• Net reproductive rate

• Carrying capacity

• Life table

Answer: Carrying capacity

A population of 500 mice inhabits an island. The resources on the island limit population to 900 mice. If the normal growth rate is 30% each year, how many mice will be added to the population this year?

• 100

• 67

• 150

• 135

Answer: 67

What’s an example of a density-dependent factor that limits population growth?

• Parasitism

• Predation

• Disease

• Competition

• All of the above

Answer: All of the above

Ecology

• The study of how organisms relate to one another and to their environments

• There ae many levels

  • Individuals, populations, community and ecosystem

Key Elements of the Environment

Temperature, water, sunlight and soil

Adaptations: Phenotypic Plasticity

• A helpful change within an individual

• Ability to change ones phenotypes

• This is a type of evolutionary adaptation

Adaptation: Evoluntionary Adaptation

An inherited trait that improves the ability of individuals to survive and reproduce

Populations

• Groups of individuals of the same species in one place at the same time

3 Characteristics of Population Ecology

• Population range, area throughout which a population occurs

• Pattern of spacing of individuals

• How the population changes in size through time

Metapopulations

• Species exist as a network of spatially distinct (and seperated) populations that have limited interaction

• Occur in areas in which suitable habitat is patchily distributed

Random Spacing

• Individuals don’t interact strongly with one another

• Not common in nature

• Position of one indivdual doesn’t affect position of another

Uniform Spacing

• Individuals are evenly spaced

• Behavioral interactions

• Resource competition

Clumped Spacing

• Uneven distribution of resources

• Common in nature

Density

• The number of individuals within a given area

• Often decreases as size of the organism increases

Demography

The quantitative study of population

Population Demographics: Sex Ratio

The ratio of females to males

Population Demographics: Age Structure

• Determined by the numbers of individuals in a different age group (cohort)

• Critical influence on populations growth rate

Age Structure: Cohort

• Each groups of individuals of the same age in a population

• Each cohort has a characteristic fecundity and mortality…

  • Which affects the overall fecundity and mortality of the population

Population Demographics: Fecundity

Number of offspring produced in a standard time period

Population Demographics: Mortality

Death rate in a standard time period

Population Demographics: Generation Time

Average interval between the birth of an individual and the birth of its offspring

Population Growth Rate

r = (b - d) + (i - e)

• r = rate of population increase

• b = birth rate

• d = death rate

• i = immigration rate

• e = emigration rate

Exponential Growth

There are two assumptions

• No net immigration or emigration

• No population growth limits

Equation: dN/dt = riN

• ri = maximum population growth rate

• N = population size

• dN/dt = change in population size per unit of time

Logistic Growth

Equation: dN/dt = rN(K - N/K)

• K = carrying capacity

Carrying Capacity

The number of individuals that can be sustained by the enviornment

Density-Independent Factors

• Factors such as natural disasters, affect populations regardless of size

• Populations display errtic growth patterns because of these events

Density-Dependent Factors

• Factors that affect the population and depend on the population size

• These are factors like food scarce, predators or territories

Negative Feedback

It keeps that populations in check through regulation

K-Selected Species

Individuals are good survivors and competitors

• Result of density-dependent factors

R-Selected Species

Individuals are good reproducers

• Species subject to frequent density-independent factors

Continuum

• Exists in reality

• Most species fall in between being r and K selected

• Exhibit combination of traits from the two extremes