EXAM 2 ZO 410 - Lectures 11 -

Epigenisis

Involves both genetic and environment influencing final phenotype

Epigenetics

Changes in the way the genes are expressed and then they become heritable

• not caused by changes in DNA sequences

• Include dominance in species as well as changes in pre-determined genders

• Example: Daphnea experience predation during lifespan, offspring will be born with helmets

Developmental Homeostasis

1. Constancy in which individuals pass through certain stages

2. Development of normal behavioral traits even when in abnormal environments (if they reach the bare minimum, they will be okay)

Harlow Deprivation experiments

Researched how rearing condition affected later social behavior.

• Experiments determined bare minimum needed for normal behavior

• Concluded that maternal care, physical contact with others, and living in a group were necessary for growing up within the critical period (birth to 6 months) in order to grow up normally.

Restricted Development

Behavior highly influenced by genetic makeup, learning has little impact

• all wiring is present at birth on how to do a behavior

Semi-Restricted Development

Genetic and environmental influence

• Critical period where experience is crucial for shaping behavior (chaffinch song)

Flexible Development

Minimal genetic influence, learning has a large role

• open template to imprint (zebra finches)

About different types of development

• Based on genetic role in behavior

• Most behaviors established during critical periods can be altered, but in very rare cases

Filial imprinting

Development of social attachment to thing or animal

• Occurs during the critical vs. sensitive period (greatest vs. possible)

• Nature and nurture (both innate and learned)

Sexual imprinting

Species-isolating mechanism

• both types of imprinting occur in species that imprint

Imprinting in Mammals

Imprint through olfactory and vocalizations

• Immediate contact with newborn is necessary otherwise imprinting will be difficult to occur

Incest taboo/avoidance

Imprinted on mind during critical period with an aversion to individual, not attachment if raised alongside person starting before 3 years old

3 types of play behavior

1. Social

2. Exercise

3. Exploration

• Animals avoid playing if hungry

Observational Learning

Learning through imitation and can occur without being reinforced (IS NOT TAUGHT)

• Cultural transmission - different amongst different species

• Genetically pre-wired for specific observational learning

Teaching

Learning from others, altering behavior to help others learn

• human children are pre-wired to learn from adults and those in power

• Bird and whale song dialects examples of teaching

Insight Learning

Making new associations between two things to solve a problem

• tool use

Anthropomorphism

Assigning human characteristics to animals

• Morgan’s Canon - animal behavior should not try to be explained by complex mechanisms but instead by simpler processes

• Evolutionary cohesiveness - Morgan argued that simpler, foundational behaviors take place before more complex ones

Umwelt in regards to humans and animals

Humans are cognitive generalists while animals are cognitive specialists.

• animals can be very skilled at one thing such as memory, smelling, sight whereas humans have a generalized ability of all many things.

Optimality Theory for foraging

Designs that are most efficient and therefore become more persistent and prevelant

• this theory aims to create more NET energy gain

• the design that increases individual’s fitness more than any other solution

Foraging choices

What food to eat?

• most animals are specialist rather than generalists

• weight out what is profitable vs. non-profitable by focusing on net gain in calories

• avoidance of toxins

Foraging currency

What is being maximized?

• energy intake = energy from food - cost to acquire

• Can assess site quality of a specific area by sampling or observing others in the spot

• unpredictable resources that may cause more energy expenditure

• Marginal Value theorem

Risk-sensitive

Animals that can consider variability in resources when deciding where to forage

• risk averse - avoid risk (most animals do this)

• risk prone - commit to still going to a specific area despite the risk

Marginal Value Theorem

Predicts when an animal will leave a patch/eating area

• If travel time to another spot increases, time at one patch will increase

• If the quality or quantity of food decreases, time at one patch will increase

Foraging constraints

Limits to foraging whether due to physical, nutrient, predation, or competition limitations

• Example of predation (chickadees foraging for seeds and will carry food away if a hawk is near by)

Sociality/Cooperative hunting

Hunting in a group

• Examples: spiders, army ants, primates, mammalian carnivores

Social Systems

Spacing, mating systems, social organization

Social spacing

Home range vs. territorial

• home range: stay with in for most of life and have core areas (only defend their area in the moment NOT the whole range

• Territories: actively defend area and exclusive use of space only for you (CANNOT eat outside of territory)

• Energy, time, risk of death, limited to that space only

• optimality of territoriality

Will an animal be territorial over an abundant or scarce resource?

• If a resource is scarce, there is no point in competing with others and wasting energy being territorial for not much benefit.

• If a resource is abundant, there’s no point in being territorial and expend energy because all organisms in an environment can have some of the resource.

• Territoriality is most favored when resources are moderately abundant.

Classical Territory

Meets many needs and the organism rarely leaves (mockingbirds)

Nesting-only territory

a protected area for raising young - generally primarily females use

Feeding-only territory

Used seasonally or year round to find and protect a food source.

Mating-only territory

Used for display and mating only and no other males are allowed inside.

• Lek system: lots of males are in one area together with their own territories, mating on their own.

Natal philopatry

Offspring remain at the area in which they were born and share the territory with their parents.

• Predator avoidance and more familiar

• Food resources are known

• Reduced aggression with neighbors

• Lower overall stress because of familiar environment

Natal Dispersal

Offspring move from birthplace and never return.

• Decreases risk of inbreeding

• Decreases overcrowding in one area

• Decreases competition for food and mates

3 Hypotheses about dispersal

1. Reduce inbreeding

2. Reduce mate competition

3. Reduce competition with parents

Birds vs. mammals

Birds: females are more likely to disperse and leave their birthing area

Mammals: Males are more likely to disperse

Reduce inbreeding hypotheses

Birds: most are monogamous

• males compete for territories rather than mates, therefore they need to be more familiar with an area.

• females in turn disperse to avoid inbreeding and to look for the best territories and mates.

• In some cases, it is dependent on if the father is present and how that affects the daughters leaving or staying

Mammals: most are polygynous

• males directly compete for females, therefore males disperse to increase their chance of finding many mates and breeding

• females often live in social groups, so males disperse to avoid inbreeding

Reduce mate competition hypothesis

Polygynous: males compete for more mates, therefore they disperse to increase their chances of breeding.

Monogamous: both males and females compete for one mate, therefore they equally disperse.

Reduce competition with parents hypothesis

Oedipus Hypothesis

• Monogamous birds: daughters forced to disperse bc of competition with mother

• Polygynous mammals: males most often disperse bc of competition with father

Ultimate and Proximate causes for male dispersal

Proximate:

1. Testerone can cause them to be more curious, less fearful, more confident and active.

2. Triggered by attainment of a particular body mass which could initiate investigative behaviors among males.

Ultimate:

1. Reduces the chance of inbreeding and can increase fitness

2. Most mammals show strong males biases in dispersal, suggesting it has been selected for directly.

Habitat preference based upon

1. Heredity: genetically coded preferences

2. Learning: habitat imprinting and learning by observing what habitats other organisms of the same species prefer.

3. Social facilitation: join others of same species and some will join a specific area if the nests have large numbers of eggs.

4. Tradition: behavior passes from one generation to the next through learning.

Migration

1. Stage of preparation - fat deposition and changes in metabolism

2. Zugunruhe - migratory restlessness and increased activity

Migration costs and benefits

Costs:

1. Energy expenditure

2. Predation risk

3. Unstable weather

4. Inhospitable terrain

5. Leaving territory unwatched

Benefits:

1. Energy profit - better food and water, better enviornment

2. Reproductive profit - more time to get food for young depending on daylight changes in diff. parts of the world

3. Some places have more protection for offspring