Bio Unit 3

Ecology

The study of relationships between organisms and their environment

Organismal Ecology

Focuses on the individual organisms' adaptations and interactions with their environment (biotic and abiotic)

Population Ecology

Study of interactions between members of the same species

Characteristics of a Population

Area/Range, Pattern of spacing, change in size through time

Fecundity

The reproductive potential of a population

Population Demography

Quantitative study of population that focuses on its changes throughout time, HINGES ON PREDATION, RESOURCES, AND DISEASE

Population growth is most affected by

Birth, death, migration, and Females r = (b – d) + (i – e)

b: birth rate, d: death rate, i: immigration, e: emigration

Cohort

Members of a population who are generally the same age

Life Table

Probability of survival and reproduction through a cohort’s life, calculated by number of deaths and number of survivors

Age structure of a population

The # of people in different age groups, has a critical influence on population’s growth rate

Main processes used to study populations

demography, population growth, and population dynamics

Survivorship

Percent of original population surviving to given age, meant to determine if species will survive or die off, represented by 3 types of curves

Type 1 curve species

Species that produces few offspring that live to an old age because of high parental care (large mammals)

Type 2 curve species

Individuals whose chance of survival is independent of age. Usually have few offspring with high parental care (birds)

Type 3 curve species

Individuals that mostly die in the early stages of their life. Have lots of offspring at once, but don't provide them with much parental care. (Trees)

Biotic potential

exponential for any population, unchecked growth in a population will lead to explosion (kudzu)

dN/dt and r

intrinsic rate of natural increase, adjusted for amount of available resources

r/k selection theory 

describes the way a species controls its number of offspring. K selected species have type 1 traits (humans), R selected ones have type 3 traits minus the long lifespan (roaches)

Ecological Footprint

The amount of land required to sustain their use of natural resources. Total footprint of humanity is 1.5, humanity uses ecological services 1.5 times as quickly as Earth can renew them

Dominant Species

Species that is the most abundant in an area 

Are humans exponential or logistic?

Exponential because they show steady growth trends and have in the past increased the world’s carrying capacity. 10 billion is estimated carrying capacity

Keystone Species 

Most influential in regards to trophic levels, it is the species that is essential to the order of the ecosystem it lives in (gray wolves, which control elk populations)

Foundation Species

Species that allows others to live in an environment by altering that environment (beavers creating dams/cutting down trees)

Intraspecific competition

Competition within a species

Interspecific competition

Competition between species

Interference competition

Competition that takes the form of direct physical interactions between species

Exploitative Competition

When species indirectly compete with each other by consuming the same resources

Competitive Exclusion Principle

States that no two species can occupy the same niche. Those who use the resources more effectively are selected for that niche (GF Gause experiment with 3 species of paramecium)

What are some mechanisms that species can use to avoid competition?

intimidation tactics, camoflauge, isolation mechanisms, symbiotic relationships

Symmetric Trajectory

When two species that occupy the same niche live separately, they show a very similar pattern of growth

Asymmetric Trajectory

When two species that occupy the same niche live together, one may end up outcompeting the other to death. (P. aurelia killing off P. caudatum). There is an exception as sometimes it is possible for species to coexist if they divide their resources well.

Ecological Niche 

total range of conditions under which an individual (or population) lives and replaces itself

Resource Partitioning

Sharing of resources by similar species occupying the same niche, is a result of Natural Selection

Character Displacement

Differences in morphology between sympatric species to reduce competition in the same environment (populations/species that occur in the same place at the same time) (darwin’s finches)

Batesian Mimicry

When a harmless species develops camoflauge to look like a more harmful species (milk snakes and coral snakes)

Mullerian Mimicry

when related/unrelated dangerous organisms have similar warning systems, like bright colors, to protect from predators (butterflies mimicking more poisonous butterflies)

Aposematic Coloration

advertising by an animal to potential predators that it is not worth attacking or eating. (poison dart frog or skunks)

Green world hypothesis

proposes that predators are the primary regulators of ecosystems: they are the reason the world is 'green', by regulating the herbivores that would otherwise consume all the greenery.

Why don’t herbivores eat everything?

90% of plants end up with decomposers, it takes time to determine which plants are best suited for eating, many plants are low in nutritional quality

Ectoparasites

Live on the surface of the host

Parasitoidism

deposit eggs in/on the host

Endosymbiont

Live inside one another

Clownfish and anemones

Mutualism

Remora and shark

Commensalism

Biological communities are characterized by species…

richness (number present), abundance, relative abundance (How common or rare relative to others), and diversity (Species richness and evenness of species abundance)

Evapotranspiration 

The release of water into the atmosphere in the form of water vapor by evaporation, respiration, and transpiration. As it occurs more, species richness increases (IT IS A KEY INDICATOR OF COMMUNITY COMPOSITION)

4 main abiotic biogeochemical cycles

Water, carbon, nitrogen, phosphorus

Nitrification

The biological oxidation of ammonia/ammonium to nitrite followed by the oxidation of the nitrite to nitrate. Nitrogen sources from the atmosphere via nitrogen-fixing bacteria. This nitrogen and nitrogenous waste from animals is converted back into gaseous nitrogen by soil bacteria, which also supply food webs with the organic nitrogen they need.

How does energy exist?

In the form of heat, light, chemical-bond energy,

First law of thermodynamics

Energy is neither created nor destroyed, rather changes forms

Second law of thermodynamics

Some chemical bond or light energy can be converted into heat (entropy)

Photoautotroph 

Organisms that use light energy to produce organic materials needed to sustain their own metabolism (plants, certain bacteria)

Chemoautotroph

An organism that takes inorganic chemicals and transforms it into energy. (ORGANISMS IN THE CAMBRIAN ERA THAT WOULD USE GEOTHERMAL VENTS AS FOOD)

Why are venus flytraps primary producers?

IT TECHNICALLY DOES NOT EAT THE BUG, It decomposes them and uses their chemicals like fertilizer

Order of levels

Primary producers, herbivores, primary carnivores, secondary carnivores, detritivores (physically break down decaying matter)

Why are decomposers important

essential for recycling the finite matter that occupies physical space in the biome.

Limiting nutrients

Nutrients that exist in the shortest supply and limit growth. For terrestrial and aquatic ecosystems, it is nitrogen and phosphorus

Gross Primary Productivity (GPP)

Rate at which primary producers incorporate energy from the sun.

Net Primary Productivity