AP BIO Ch 40-43 Ecology

Ecology

Scientific study of interactions among organisms and between organisms and their environment

Population

group of individuals of the same species that live in the same area

Community

All the different populations that live together in an area

Ecosystem

the community of organisms in an area and the physical/abiotic factors with which they interact

landscape

a mosaic of connected ecosystems

Biosphere

Global sum of all ecosystems on Earth.

global ecology (biosphere)

examines how the regional exchange of energy and materials influences the functioning and distribution of organisms across the biosphere

Landscape ecology

focuses on the factors controlling exchanges of energy, materials, and organisms across multiple ecosystems

Ecosystem ecology

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

community ecology

The study of how interactions between species affect community structure and organization

population ecology

analyzes factors that affect population size and how and why it changes through time

The mist significant influence on the distribution of organisms on land:

Climate

climate

The long-term average weather condition at a particular location

Four major components that make up climate:

temperature, precipitation, sunlight, and wind

Global climate patterns are determined by:

input of solar energy and Earth's movement in space (latitudinal variation, air circulation and precipitation patterns..)

The changing angle of the sun over the year, odies of water, and mountains exert:

Seasonal, regional and local effects on climate

Biomes

Major life zones characterized by vegetation type in terrestrial biomes

Climograph

A plot of the annual mean temperature and precipitation

Main 6 biomes:

Desert, Temperate grassland, temperate broadleaf forest, tropical forest, northern coniferous forest, tundra

Desert

30-50 degrees C, low precipitation (30 cm yearly), low-widely spread vegetation

Tropical Forrest

25-29 degrees C, 200-400 cm yearly rain, 6-7 dry months, vertically layered,millions of species

Temperate grassland

30-100 cm yearly rain, -10 - 30 degrees C, low vegetation spread out

Temperate broadleaf forest

70-200 cm yearly rain, 0-35 degrees C, deciduous trees

Northern coniferous forest

Largest terrestrial biome, 30-70 cm yearly rain, -50 degrees C - 20,

Tundra

20% of earth, high wind, low temp 20-60 cm, -30 - -10 degrees C

Disturbance

Storm, fire, human activities (removes organisms and alters resource availability)

Aquatic biomes are characterized by by ..

Physical and chemical environment

Marine and freshwater biome salt concentrations

Marine- 3.5% salt, freshwater - <.1% of salt

Photic zone

The region where there is sufficient light for photosynthesis

Aphotic zone

Zone where little light penetrates

Benthic zone

The bottom of the body of water with rocks and sediments

Benthos

Community of organisms that live in the benthic zone

Littoral zone

Are close to the shore and extending out of the edge of the continental shelf

Pelagic zone

The whole water column (vertically)

Limnetic zone

Further out from shore

Thermocline

Narrow layer of abrupt temperature change that separates the warm upper layers from cold deeper water

Marine algae and photosynthesis bacteria supply much of the world's:

Oxygen and consumes large amounts of atmosphere if carbon dioxide

Oligotrophic lake

Lake that is nutrient poor and oxygen rich (sterile)

Eutrophic lake

Lake that is nutrient rich and oxygen poor when heterotrophs use up oxygen at the end of the summer

Estuary

Transitional area between river and sea, water in this area is described as brakish because of its mixture of fresh and salt water

Wetland

Habit inundated by water at least some of the time and supports plants that are adapted to water saturated soil

Intertidal zone

Area that is periodically submerged and exposed by the tides

Species distributions are consequences of:

Both ecological factors and evolutionary history

Dispersal

Movement of individuals away from their area of origin or from centers of high population density

Abiotic factors

Temperature, water and oxygen, salinity, sunlight, rocks and soil

Population ecology explores how biotic and abiotic factors influence:

Density, distribution, and size of a population

Population density

Number of individuals per unit of area or volume

Patterns of dispersion

Pattern of spacing among individuals within a population

3 patterns

Clumped, uniform, random

Demography

Study of the vital statistics of populations and how they change over time

Life table

Age-specific survival and reproductive rates of individuals in a population. Produced by following the fate of a cohort (group of individuals of the same age from birth until death)

Type 1 survivorship curve

Low death rate at birth and middle life and then death rate increase sharply in older groups. Low infant mortality bc of good parental care (ex humans)

Type 2 survivorship curve

Intermediate between 1 and 2. Constant rate of birth and death (ex squirrels)

Type 3 survivorship curve

High death rate in early life, but death rate decreases for older age groups, large numbers of offspring and no parental care (ex oysters)

Population growth rate - number of individuals in a given area over time

R= b-d/N

Intrinsic rate of increase

The per capita rate at which an exponentially growing population increases in size at each instant in time (assume ideal conditions) (r max)

Life history

The traits that affect an organism's schedule of reproduction and survival

Due to limited resources there must be a tradeoff between

Number of offspring and the amount of resources a parent can devote to each offspring

Variables that influence life histories:

1. When reproduction begins (age of maturity), 2. How often the organism reproduces, 3. How many offsprings are produced per reproductive episode

K-selection

Selection of life history traits that are sensitive to population density and carrying capacity, also known as density-dependent selection

R-selection

Selection of life history traits that maximize reproductive success in uncrowded environments, also known as density-independent selection (boom or bust populations)

At large population sizes, negative feedback is provided by density-dependent regulation, which

Halts population growth through mechanisms that reduce birth rates or increase death rates

Density dependent mechanisms (usually biotic):

Competition for resources, territoriality, disease, intrinsic factors, waste accumulation, predation

Population dynamics

Population fluctuations from year to year or place to place

Meta-population

When a number of local populations (of the same species) are linked

Interspecific competitions

when populations of two different species compete for the same limited resource (-/-)

competitive exclusion

theory that states that no two species can occupy the same niche at the same time

resource partitioning

the differentiation of niches that enables similar species to coexist in a community

ecological niche

the sum of a species' use of the biotic and abiotic resources in its environment

Organisms's niche

Its ecological role - how it fits into an ecosystem

fundamental niche

The full potential range of the physical, chemical, and biological factors a species can use if there is no competition from other species.

realized niche

the range of abiotic and biotic conditions under which a species actually lives

character displacement

The tendency for characteristics to be more divergent in sympatric (geographically overlapping areas) populations of two species than in allopatric (geographically isolated) populations of the same two species.

cryptic coloration

camouflage

aposematic coloration

Bright warning colors in animals with a chemical defense.

Batesian mimicry

a harmless species mimics a harmful one

Mullerian mimicry

When two or more harmful species resemble each other

Herbivory

An interaction in which an herbivore eats parts of a plant or alga (+/-)

2 ways in which plants defend against predators

Chemical toxins and spines and thorns

Symbiosis

A relationship in which two different organisms live in close association with each other

Parasitism

One organism benefits and the other is harmed (+/-)

Endoparasites

live inside the host

Ectoparasites

parasites that live on the external surface of a host

Parasitoids

organisms that lay eggs inside other organisms or on the outside

Mutualism

A relationship between two species in which both species benefit (+/+)

Commensalism

A relationship between two organisms in which one organism benefits and the other is unaffected (+/0)

Species diversity

Variety of different kinds of organisms that make up a community.

species richness

the number of different species in a community

relative abundance

the proportion each species represents of all individuals in the community

Biomass

the total mass of organisms in a given habitat

trophic structure

Feeding relationships between organisms in a community.

trophic level

step in a food chain or food web

food chain vs food web

Chain is simplified illustrating energy flow and a web is a complex arrangement of food chains.

dominant species

Species that are the most abundant or have the most biomass.

keystone species

a species that has an unusually large effect on its ecosystem

stability

Community tendency to reach and maintain constant composure of species

intermediate disturbance hypothesis

the hypothesis that ecosystems experiencing intermediate levels of disturbance are more diverse than those with high or low disturbance levels

ecological succession

transitions in species composition in a certain area over ecological time (often result of disturbance)

primary succession

succession that occurs on surfaces where no soil exists

pioneer species

First species to populate an area