Ecology

Ecology

Ecology

The science of the relationships between organisms and their environments.

Organism

an individual living thing that uses energy, reproduces, responds, grows, and develops

Species

a group of similar organisms that can breed and produce fertile offspring

Population

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

Community

all living, or biotic, things in an area

Ecosystem

all biotic (living) and abiotic (nonliving) things in an area

Autotroph

• also known as a producer

• an organism capable of making its own food from inorganic substances using light or chemical energy.

• eg. Green plants, algae, and certain bacteria

Heterotroph

An organism that obtains organic food molecules by eating other organisms or substances derived from them.

Carbon cycle

the continuous process by which carbon is exchanged between organisms and the environment

Energy flow

• sunlight is the source of energy for most ecosystems

Trophic level

step in a food chain or food web

Food chain

shows the transfer of energy between organisms.

producer --> primary consumer --> secondary consumer --> tertiary consumer

eg. passion flower --> heliconius butterfly --> tegu lizard --> jaguar

the energy in the carbon compounds (food) is released through respiration. much of this energy is lost as heat.

Food web

network of complex interactions formed by the feeding relationships among the various organisms in an ecosystem

Pyramid of energy

• diagram that shows the relative amounts of energy or matter within each trophic level in a food chain or food web

• should be stepped

• the length of the bar represents the amount of energy transferred to the trophic level (resulting in an increase in biomass)

• the unit = KJ m^-2 yr^-1

• around 10% of energy at any trophic level is passed on to the next trophic level

• the number of trophic levels is limited, as there is ever decreasing quantities of energy available for transfer and the energy is passed along the food chain.

• reasons for loss of energy between the trophic levels include:

• energy is lost as heat due to respiration

• not all of the individuals at each trophic level is consumed

• not all parts of the organism can be digested.

10% Rule

Only 10% of the energy in one trophic level gets passed onto the next trophic level

Biological magnification

increasing concentration of a harmful substance in organisms at higher trophic levels in a food chain or food web

Producer

organism that can capture energy from sunlight or chemicals and use it to produce food from inorganic compounds

also called an autotroph

Consumer

organism that relies on other organisms for its energy and food supply

also called a heterotroph

Primary Consumer

Consumer that feeds directly on producers The animal that directly eats the producer

this category includes organisms that consume producers (plants and algae).

Secondary Consumer

An organism that eats primary consumers

A member of the trophic level of an ecosystem consisting of carnivores that eat herbivores

Tertiary Consumer

An organism that eats secondary consumers

The third trophic level of consumer in a food chain

Detritivore

organism that feeds on plant and animal remains and other dead matter (ex. vultures, earthworms, crabs, etc.)

Saprotroph

an organism that lives on or in non-living organic matter, secreting digestive enzymes into it and absorbing the products of digestion (e.g. mushrooms, bacteria)

Obtains nutrients from decaying organic matter

Precautionary Principle

The principle that states that when an activity raises threats of harm to human health or to the environment safety should prevail in control measures should be initiated even if cause-and-effect relationships are fully established

Detritus

nonliving organic matter

typically includes decaying dead organisms as well as fecal matter

Habitat

the area where an organism lives, including the biotic and abiotic factors that affect it

Limiting factor

factor that causes the growth of a population to decrease or not grow any larger (ex. food, water, shelter, predation, disease, etc.- abiotic or biotic factors)

External factor

any living or nonliving factor that impacts the survival of an organism, population, or community (can be a limiting factor or a non-limiting factor)

Abiotic

non-living

Biotic

living

Greenhouse effect

is a natural phenomenon which maintains temperatures required for life to live on Earth.

short wave (visible light) radiation from sunlight passes through the Earth's atmosphere and strikes the surface of the planet.

much of the light is reflected, but some is absorbed and transferred to heat. the earth radiated the hear as infrared (long wavelength) into the atmosphere.

the greenhouse effect traps some of the heat keeping the atmosphere warm

most important greenhouse gases = CO2 & H2O (methane and nitrogen also contribute to greenhouse effect)

if the concentration of green house gases increase, more heat will be trapped. there is evidence that this is happening due to human activities (eg. combustion of fossil fuels)

Potential problems associated with climate change

1. ice habitats are melting (destruction of habitats)

2. flooding (destruction of habitats)

3. desertification

4. more extreme weather events

5. species extinction

6. movement of species further north=

7. destruction of food webs

Microorganism

an organism that is microscopic, or too small to be seen by the unaided human eye

examples include bacteria, archaea, most protists, and some fungi (viruses, although microscopic, are not considered microorganisms because they are non-living)

Quadrat Sampling

Using a known small area at random to count organisms within that area. The number of organisms within that area can give an approximate estimate of the population of that particular species in a larger area.

Transect

use string across a place where you collect data, collect the data of whatever passes the string

Fundamental Niche

all of the places a species can live if no competition

The entire range of resource opportunities an organism is potentially able to occupy within an ecosystem

Natality

Birth rate increases population size as offspring are added to the population

Immigration

Migration to a new location, Movement of individuals into a population

Emigration

Movement of individuals out of an area.

Mortality

Death rate

Competition

A common demand by two or more organisms upon a limited supply of a resource

for example, food, water, light, space, mates, nesting sites.

Predation

An interaction in which one organism captures and feeds on another organism

Parasitism

A relationship in which one organism lives on or in a host and harms it.

Mutualism

A relationship between two species in which both species benefit

Biomass

A measure of the total dry mass of organisms within a particular region.

Biosphere

The area on and around Earth where life exists.

Biome

A group of ecosystems that share similar climates and typical organisms.

Invasive Species

species that enter new ecosystems and multiply, harming native species and their habitats

Biomagnification aka Bioaccumulation

accumulation of pollutants at successive levels of the food chain

the process by which the concentration of toxic substances increases in each successive link in the food chain

CFCs

Chlorinated Fluorocarbons are chemicals that break down the ozone layer

Trophic Level

Each step in a food chain or food web

The position of an organism in relation to the flow of energy and inorganic nutrients through an ecosystem (e.g., producer, consumer, and decomposer).