Ecology BEHAVIORAL BIOLOGY

Gene (nature) and environment (nurture) influence one’s behavior.

Gene= innate behavior

Environment= learned behavior from parents and trial and error.

Ethology : study of animal behavior

Fix Action Pattern (FAP): Ex: 3 spine stickleback attacks other fish that invade its territory and non-fish like models with a red underside. Sign stimulus= the red underside & response= attack by the stickleback.

Genes influence behavior but do not dictates it.

Behavior evolved is because it made that organism better to “fit to the environment” or optimized that organisms’ Darwinian fitness.

Feeding/foraging is essential to survival and reproductive success.

What animal eats is based on optimal foraging.

Optimal Foraging: weighing the cost and benefits of getting a meal. Ex: bluegill sunfish feeds on crustacean called Daphnia. Bluegill sunfish wants the most energy/food at the least cost/energy lost. Larger Daphnia= offer more energy. Large preys are farther away, bluegill sunfish will select closer, smaller prey.

Habituation (Cry wolf effect): a type of learning that involves a lost of responsiveness to a stimulus. Ex: Hydra stopped moving after poking too long.

Time range=critical period.

Imprinting= learning linked to a specific window of time. And is usually irreversible.

Konrad Lorenz: imprinting experiments with newborn geese. He found that if geese spend time with a human after hatching, from that day on they will follow that person and show no sign of recognizing their own mother or other geese. Critical period for geese is two days after hatching to imprint parental bonding.

Associative Learning: the ability of animals to learn to associate one stimulus with another. Two types: (1) Classical Conditioning (2) Operant

Classical Conditioning: when an ARBITRARY STIMULUS is associated with a reward or punishment. Pavlov: classical conditioning experiments done with dogs, ring a bell, and then spray powdered meat into the dog’s mouth and causing them to salivate. Eventually, the dogs learned to ASSOCIATE THE ARBITRARY BELL to a reward.

Operant Conditioning: when an animal learns to associate its OWN BEHAVIORS with a reward or punishment. B. F. Skinner: famous for operant conditioning experiments done with birds and rats placed in a skinner’s box. Inside the box, the rat had to find and push a lever (usually by accident the first few times) and then it was rewarded with a piece of food. The rat then quickly learned to “ASSOCIATE” pushing the lever the getting a treat on ITS OWN.

Learning also takes place when animals play.

Play behavior enables animals to practice skills, such as catch prey. Also helps animals practice (1) social roles (2) sexual roles to perfect behaviors.

Cognition: to think or solve a problem

Cognitive ethology: study of animal cognition. Ex: Jane Goodall works with chimps.

When it comes to animal movement, many animals form cognitive maps.

These are symbols of spatial relationships of objects in their environment Birds migrate by using environmental cues such as the location of the sun, star, and earth magnetic field.

2 kinds of movements: (1) taxis (2) kinesis.

Taxis: toward or away from a stimulus.

Kinesis: change in activity rate in response to a stimulus. Ex: moths attracted to lights (taxis), moves around the light (kinesis).

Sociobiology: study of social behavior between 2 or more animas, concerned with behaviors such as aggression, courtship, cooperation, and deception. Emphasizes these social behaviors have evolution and thus maximize species success.

Niche: an organism’s role= its habitat, what it eats, whom it mates with and when, etc

Because members of a population share a common niche, there is a strong potential for conflict amongst the same species living in one area competing for food or a mate brings competitive social behaviors/ agnostic behavior.

This contest involves both (1) threatening and (2) submissive behaviors to determine 1 winner. Agnostic-behavior animals establish a Dominant Hierarchy/ pecking order.

Ex: Hens, α or top-ranked hen controls the behavior of all others. The β or second-ranked controls all beneath her in the hierarchy, except the α hen. Ω is the lowest animal.

Home range: everywhere an animal wanders but doesn’t defend.

Territory: strongly defended, provides the animal with food, breeding area, and places to raise young. It usually limited to 2 species competing for the same niche in the environment.

Females are always choosier than males.

Females have a greater parental investment than males.

Females invest more time, energy, and resources to produce offspring. Eggs are much larger than sperm.

Males then to mate with as many females as possible.

“Chosen Male” males have evolved 20 characteristics to advertise their Darwinian fitness. Ex: bright plumage in birds, large antlers in deer, good genes, healthy.

Many males engage in ritualistic courtship behaviors to attract the attention of a female. Ex: Albatross birds: highly choreographed clicks, sounds, and movement.

In many species, mating is promiscuous- no strong lasting relationship.

Some animal species have Monogamous relationship- mates remain together for a longer period. May help leave more viable offspring because both parents help raise the young.

Polygamy: an individual of one sex mates with several others. 2 types: (1) polygyny (2) polyandry

Polygyny: one male mates with several females.

Polyandry: one female mates with several males.

Most animals are Nocturnal, rely on auditory, sound signals, or olfactory, scent signals, such as pheromones.

Altruism: animals behave in a way that reduces their individual fitness for the benefit of others. Ex: a squirrel gives off high pitched alarm call to alert the others about the predators getting closer.

Altruistic behavior is usually done when members of a population are related to some degree.

Coefficient of Relatedness: determines whether altruistic behavior will occur. Ex: Siblings genes have a coefficient of relatedness of 50%. Cousins have 12.5%.

Parents are most likely to exhibit altruistic behavior.

Reciprocal altruism: some animals behave altruistically towards non-relatives (very rare, limited to humans). Ex: Wolves may offer food to other wolves even though they share no kinship.

THE BIOSPHERE Ecology: the study of the interactions between organisms and their environment.

Environment: 1) biotic—living factors, ex: animals, plants, fungi, protest, bacteria. 2) abiotic—non-living factos, ex: rocks, temperature, precipitation.

All Ecological interactions have come about due to evolution.

Levels of Ecology: 1) Organism: one individual.

2) Population: Many organisms of the same species living in one area. 3) Community: Many populations of different species living in one area. 4) Ecosystem: Community + abiotic factors in one area.

Biome: a type of ecosystem that occupies a large geographic region. 5) Biosphere: the sum of all the ecosystems.

Factors that account for the different biomes: 1. Temperature 2. Precipitation 3. Light 4. Wind 5. Rocks (limestone, buffers lake pH) 6. Soil (evergreens decrease pH) 7. Volcanoes 8. Latitudes 9. Fire 10. Proximity to water. (Water has high specific heat buffers temps on land)

Climograph and Climatograms plot temperature and precipitation for the biomes.

Air circulation influences biomes.

1. Sunlight strikes the equator directly. 2. Water evaporates. 3. Water condenses to form clouds 4. Clouds get saturated and rain in the tropics. 5. Dry air circulates north and south of the equator creating desert biomes. 6. Due to osmosis, water near 30 N and S of the equator will go from a high to low conc. and evaporate creating

temperate zones at the Tropics.

Rain Shadow: mountains get in the way of air masses. Warm, moist air rises on the windward side of a mountain and it rains. Leaving dry, desert conditions on the leeward side of the mountain.

Turnover: mixes oxygen rich water from the surface of a lake with nutrients at the bottom in spring and fall.

Aquatic Biomes: Photic zones require light. Aphotic zones do not receive light.

1. Benthic zone: bottom of the lake. Lots of dead organic matter called detritus. Detritivores (crabs and decomposers, bacteria) feed on this.

2. Littoral zone: shallow and close to the shore 3. Limnetic zone: photic, open water, rich in photosynthetic phytoplankton. 4. Profundal zone: aphotic, open water but deeper.

Oglotrophic Lake: nutrient poor, oxygen rich. (Nutrients= algae/phytoplankton)

Eutrophic Lake: nutrient rich, oxygen poor.

Mestotrophic Lake: somewhere in between the eutrophic and oglotrophic lake.

Eutrophication/algal bloom: too much algae, fertilizers, agricultural runoff, phosphates, nitrate. Decomposers and detritivores eat dead algae, consume O2, fish dies.

Regulators: maintain a stable internal environment/ homeostasis. Ex: fish, mammals/ warm blooded/ endotherms.

Conformers: change with external environment. Ex: ectoderms/ cold blooded animals.

Principle of Allocation: you only have so much energy, so allocate where it goes—some energy is used to get food, some to mate, grow.

Physiological response: short-term, internal changes. Ex: hot days, blood vessels dilate to release heat.

Morphological response: an external change in appearance. Ex: Rabbit change its fur color during winter.

Behavioral Response: quick response by an organism. Ex: desert animals often burrow below ground during the day to avoid the heat. 8 Biomes:

1. Tundra/ arctic/ apine: very cold, very short growing season, permanently frozen ground, northern, alpine mountain tops. Moss/ mat-like vegetation, no trees, snowy owls, caribou, deer, arctic foxes.

2. Taiga/ coniferous/ boreal forest: very cold, long winters, 4 seasons, northern forests (Canada), modified spikes for leaves (evergreen), bears, wolves, moose, rabbits.

3. Temperate/ deciduous forest: 4 seasons, NE & middle US, W. Europe, Deciduous trees (lose leaves in the winter), deer, wolves, small mammals. Few fires are to be expected

4. Temperate Grassland/ prairie: Hot summers, cold winters, nutrient rich, soil (wheat, corn), Western N.S. and N. Africa. Few to no trees, grasses, bison, prairie dogs, foxes. Fire occurs a good amount but not regularly.

5. Chaparral: mild/ rainy winters, hot/dry summer, Southern California, Mediterranean, spiny evergreen, shrubs, grasses, coyotes, foxes. Fire is regular. Plants have evolved to spread/ release their seeds when exposed to fire.

6. Desert: Arid/ little rain. Increase temperature during the day, cold at night. Western N.A., Eurasia, Africa, cacti, succulents, waxy leaves, prevent water loss, snakes, lizards, nocturnal animals.

7. Savanna/ tropical grassland: rainy season, drought season, Africa, grass and scattered trees, elephants, giraffes. Fire is regular. Plants have evolved to spread/ release their seeds when exposed to fire.

8. Tropical Rainforest: high rainfall, hot, poor soil due to rapid recycling, S. A, vertical stratification (canopy, epiphytes (Spanish moss with trees, commenalism relationship), shrubs, leaf litter), monkeys, sloths, crocodiles.

POPULATION ECOLOGY Population ecology: study of the changes in population size and composition.

Density: # of individuals in population.

To measure density, 3 methods: 1) Count the number of nests, burrows, droppings, or tracks. 2) Mark-recapture method= select a population to randomly sample and tag them. Release the tagged organism; in a few days catch them again and make note of which are tagged versus not tagged. Formula: 1st catch * 2nd catch/ # of tagged recaptures 3) Quadrant sampling= grid off an area, then randomly select quadrants to sample. Ex: (# of trees/ # sample area) * # of grids.

3 types of population dispersion: 1) clumped ex: school of fish 2) random ex: plants 3) uniform ex: birds

Age structure: # of individuals of each age.

Natality/ fecundity: birthrate.

Mortality: death rate.

Generation time: time between birth of an individual and the birth of their offspring.

Small organisms usually have short generation times.

Sex structure: how many of each sex are in a population.

# of females directly related to expected births.

# of males is less significant, which is why deer hunting allows for killing more bucks than does.

Life table: determine how long, on average, an individual of a given age is expected to live.

Survivorship curve: one way to visually represent the info gained in a life table. Type I: Human: low death rate early in life because they care for their young. Death rate increases with age. Type II: Squirrels or Hydra: constant death rate at all ages. Type III: Mollusks, turtles, fish, insects: high death rates early in life because of little to no parental care. *** Most species fall somewhere in between these basic types of survivorship curves.

One factor that influences fecundity and death rates has to do with the # of babies a female has. Ex: A small clutch size means less energy is invested= longer life for the mother.

Having fewer well cared for offspring means that the offspring have a greater chance for survival.

The longer a female waits to have her offspring, the shorter her life will be because she will have invested her energy into her own growth and maintenance.

Semelparity: an organism has a single, large reproductive effort. Ex: annual plants which are short lived.

Iteroparity: an organism has fewer offspring over a long time span of many years. Ex: perennial plants invest more energy into roots to return growing season and freeze resistant and/or drought resistant buds.

In vivo= in nature; in vitro= in glass.

N= population size; K=carrying capacity; r= population growth rate (birth-deaths); t=time

Some populations grow exponentially/ J shaped curve. This type of growth comes about when a population is introduced into a new area with unfilled niches, after a catastrophic (fire), or in a laboratory situation.

Other populations reach a plateau or leveling off point as the population increases logistic growth/ S-shaped curve. This type of

growth results because there is only so much food, space, and water available in the environment, so population cannot grow forever. It has a carrying capacity- point where the population stabilizes due to limited resources.

Life-history: traits that affect an organism’s mode of reproduction and death. Can be either r-selected (exponential growth) or K-selected (logistic growth) populations. (look at the notes)

Interspecific competition: competition between 2 different species.

Intraspecific competition: competition among members of the same species. Ex: 2 penguins occupy the same niche. Therefore both want access to the same resources (food, mates, shelter, etc).

Population growth rates are affected by Density-dependent factors: population increases, or become more dense, resources become more limited, so mortality rate increases. Ex: plants are grown under crowded conditions. These plants tend to be smaller and not as healthy. Diseases, famine.

Population density increases when births outnumber deaths.

Density independent: affect the population randomly. Ex: cold spell, hurricane, fire. Their actions are “independent” of population size/ density.

Boom and bust cycle: populations of insects, birds, and mammals fluctuate in density with remarkable regularity. Ex: as hare population increase, lynx increase. Feed on hares, hare pop.

decreases, lynx pop. decreases. This is DEPENDENT FACTOR!!

Species richness: # of different species

Relative abundance: how many of each of the different kinds.

Species diversity: species richness+ relative abundance. It is greatest when disturbance to an area are moderate because moderate disturbances make some pace available for new organisms to enter, but keep some of the original species intact.

Coevolution: when 2 species interact with each other and affect each other’s adaptation. Ex: bees and flowers evolved together. Bees drink nectar at the flower and inadvertently pick up pollen with their bodies and pollinate the flowers.

Symbiosis/symbiotic relationships: 2 species interact. Can be good, bad, or neutral. 4 types of symbiosis: 1) parasitism or predator (+, -) Ex: lion eats a antelope or a lamprey sucks the blood Of a fish 2) competition (-,-) Ex: bucks fighting for a mate 3) commenalism (+,0) Ex: Barnacles attach themselves to the backs of whales 4) mutualism (+,+) Ex: A lichen is made up of a fungus and an algae. The fungus Provided support and holds moisture, while the algae gives food.

Some plants have evolved defense mechanism to reduce predations by herbivores. Ex: thorns, microscopic crystals, distasteful/harmful chemicals.

Some animals have coevolved a reciprocal evolutionary adaptation. Ex: larvae of monarch butterflies eat milkweed—it’s toxic—both the larvae and the adults then store the milkweed in their tissues to make themselves distasteful to predators.

Cryptic coloration: camouflage

Deceptive coloration: large false eyes spot on the wings of some moths.

Aposematic coloration: bright colors to warn predators that the prey has chemical defenses, such as bright blue, red, yellow poison dart frogs.

Batesian mimicry: a harmless species mimics a harmful model.

Mullerian mimicry: 2 or more harmful aposematically colored species resemble each other. Ex: black with yellow stripes bees or black +yellow+ red stripes snakes= not tasty/ harmful.

#1 has the greater species diversity

Endoparasties: internal such as a tapeworm

Ectoparasites: external such as ticks, lamprey, mosquito, leech.

Competitive Exclusion Principle: when 2 species with similar niches exist in the same community one will be more efficient at gaining access to resources and drive the other out or to extinction.

Fundamental niche: resources an organism can theoretically use

Realized niche: resources an organism can really use

Sympatric: populations in the same geographic area that interact. Resources partitioning occurs.

Resources partitioning: similar species may consume slightly different foods or use other resources in a slightly different way to decrease competition.

Allopatric: populations in different geographic areas and therefore do not interact (perhaps separate by a mountain).

Keystone species: 1 species make a strong impact on the entire community structure, often causes extinction and severely decrease the food source.

Biomagnification: a thing that was once not at the top of the food chain, but later make its way up the food chain and affect all species linked to it.

Sometimes invasive/exotic species are introduced (often accidentally) into a community and greatly affect the entire community. Ex: purple loose strife, zebra and quagga mussels.

Changes in a community composition are apparent after disturbances such as a large fire or a volcanic eruption.

After the disturbance, the area gets recolonized by new species.

Ecological succession: changes in species composition over time. 2 types:

1) Primary succession: when species colonize an area completely barren of life because of an absence of fertile soil. Ex: after a volcanic island forms, in a location where rocks get broken down by lichens, in sand dunes, etc.

2) Secondary succession: fertile soil is already present, but the land gets cleared for some reason. The soil is therefore available for recolonization. Ex: forests that are burned or cut down. It is quicker because the soil is intact. Therefore, lichens are not the first in the area.

Pioneer species: first species to colonize an area in succession. They get blown in by wind, washed in, or carried in by animals.

Primary succession: lichens and mosses are the pioneer species and usually physically break down the rocks and provide organic matter that will die and decay and become the soil for later successional species.

Secondary succession: weeds, grasses, and ferns are often pioneer species.

Both inhibition and facilitation are involved in succession.

One species “inhibits” others from growing while it is present in the area, it then dies and creates rich soil. This then facilitate entry for a new species.

Small islands usually have low immigration rates, high extinction rates, and low species richness because 1) hard to land on 2) less resources 3) less niches available.

The farther an island is from the mainland, the lower immigration occurs. Also extinction rates are high for islands far from the shores because 1) hard to get there 2) small gene pool 3) high vulnerability to diseases.

ECOSYSTEM Trophic levels- feeding levels.

Land Water Large carnivore 40 consumers Large carnivore Medium carnivore 30 consumers Medium carnivore Small carnivore 20 consumers Small carnivore Herbivore 10 consumers zooplankton Plants (autotroph) 10 producers phytoplankton (algae) or plants

Food chain: the pathway in which food is transferred from trophic level to trophic beginning with the 10 producers.

Food web: most feed relationships in an ecosystem are woven/ branched.

Photosynthetic autotrophs make food with light, CO2 and H2O.

Chemosynthetic organisms sustain themselves by living off inorganic chemical. Ex: bacteria live of H2S in deep sea vents on the ocean floor.

Primary productivity: an ecosystem’s entire energy budget depends on. It is the amount of photosynthesis sets the entire energy budget. The more plentiful plants and phytoplankton are, the greater the energy budget.

Gross primary productivity (GPP): allocated by plants in an ecosystem.

Solar energy from light strikes plants and converted into ATP. But not all of the energy is used for the plant to grow; some is used to perform cellular respiration. This leads to net primary productivity (NPP).

Biomass: the dry weight of organisms added to an ecosystem.

Rain forest has the greatest biomass and contributes the greatest 10 productivity in terrestrial ecosystem because of high temperature and heavy rainfall, you get rapid recycling.

Open Ocean contributes the greatest 10 productivity in aquatic ecosystem.

10% rule: the energy available at each tropic level decreases as one goes from the 10 producers up to the 30 consumers. 10% of energy is transferred going from the 10 producers to the 10 consumers (90% energy loss). Same thing it goes up.

Biomass pyramids show the amount of standing crop/ dry weight biomass in each trophic level.

English Channel has an upside-down biomass pyramid because phytoplankton reproduces rapidly and gets consumed by zooplankton.

Water cycle: 1) evaporation, 2) condensation, 3) precipitation, 4) runoff, 5) percolation (into the soil), 6) ground water, and 7) transpiration.

Ground water

Transpiration: Water loss from plants. Ground water really looks like saturated soil.

Carbon Cycle:

The carbon cycle makes carbon/organic compounds through the process of photosynthesis and breaks down the carbon compounds in cellular respiration.

Photosynthesis formula: 6 CO2+12 H2O+ Light C6H12O6 + 6 H2O +6 O2

Cellular Respiration formula: 6 O2 + C6H12O6 6 CO2+ 6 H2O+ ATP

Fossil fuels (coal, petroleum, natural gas, and oil) are natural resources and are the remains of detritus that accumulated faster than decomposers could break them down millions of years ago.

CO2 is the gas causing the greenhouse effect and global warming.

H2O and CO2 trap in this solar infrared radiation and reflect it back towards the earth.

Nitrogen Cycle:

78% of the atmosphere is nitrogen (N2). Plants need it in the form of NH4

+ (ammonium) or NO3- (nitrate).

Nitrogen fixation: taking N2 from the atmosphere and having it converted to NH3 by nitrogen fixing bacteria called rhizobia living on the roots of legume plants like beans, peas, clovers, and peanuts. This is a mutualistic relationship.

The bacteria live in clumps on the roots called nodules.

Rhizobia fix nitrogen because they need it to make nucleic acid and protein.

Rhizobia give nitrogen to the legume plants to make proteins and nucleic acids as well.

Ammonification: NH3 is converted into NH4+. The soil is usually slightly acidic and readily yields H+ ions. It is not only

when ammonium is made from ammonia, it is also when nitrogen from dead organic matter (proteins and nucleic acids of dead plants and animals) is returned to the soil in the form of ammonium by decomposers like fungi and bacteria.

Nitrification: A species of free-living soil bacteria convert some of the ammonium into NO2- and then a second species of

soil bacteria converts it into NH3-.

All other plants must get nitrogen in the form of NH4+ or NO3

-.

Denitrification: when another type of free-living soil bacteria converts NO3- into N2, thus completing the nitrogen cycle.

Agricultural practices can interfere with nitrogen cycling. Ex: practice of logging changes the Nitrogen Cycle.

Plants usually take in nitrates, but without trees, the nitrate levels get increased in the soil and leech off into creeks. And thus cause eutrophication in lakes.

Phosphorus Cycle:

Organisms need phosphorus to build nucleic acid, phosphorus bilayer, and ATP.

Phosphorus minerals are used to build strong bones and teeth.

It is found in

one form PO4-3 phosphate.

It comes from dead organic matter and from the weathering/ erosion of phosphates from rocks. Plants get it from the soil and animals get it from eating plants. It also causes algal bloom and eutrophication. CFC (chlorofluorocarbons) used in refrigeration, air condition, and some aerosol cans causing the hole in the

ozone layer above Antarctica, broken O3 to O2. Eutrophication= fertilizers: phosphate and nitrate

Greenhouse effect/global warming (main gas H2O) = burning fossil fuels CO2. Also from CH4 released from swamps and cattle.

Hole in the Ozone: CFC

Acid rain= sulfur oxides and nitrogen oxides.

PO4-3 in soil

Pull nitrate

Erosion Watering

Plate tectonics Rocky Mts.