Unit 2: EcologyChapters 2-5

What is Ecology?

A branch of __ that studies the interactions that take place between __ and their __

The Environment Abiotic Factors – The __ parts of an

organism’s environment Ex) air currents, __, moisture, __, and soil

Biotic Factors – All the __ organisms that inhabit an environment This includes an organisms relationships with

other organisms. They depend on each other for __

Levels of Organization 1) Organism - __

Ex) __

2) __ – A group of organisms, all of one species, which interbreed and live in the same place at the same time

Ex) A __ of dogs in an area

3) __ – All the populations of different species that live in the same place at the same time

Ex) dogs, cats, mice, insects, dandelions, grass, etc…

Levels (cont.) 4) Ecosystem – Made up of interacting __ in a

given area and with the __ components of that area Two Types:

A) Terrestrial – located on __ B) Aquatic – __.

5) __ – The portion of the earth that supports life.

Extends from high in the atmosphere to the bottom of the __

Organisms in Ecosystems Habitat – __

Ex) lawn, stream, forest Can change or disappear

__ – all strategies and adaptations a species uses in its environment Ex) how it meets its specific needs for __ and __, how

and where it survives, and where it reproduces. It is an __ for a species to occupy a niche different

from those of other species in the same habitat

Relationships in Ecosystems A. __

Organisms may compete with each other for food, water, mates, sunlight, space, etc… Ex) cattle and sheep Ex) plants for __

Competition also increases when resources are in __

Affects the __ of a species When a population increases to a point in which

demand of the resources exceeds the supply, the population size __

Competition (cont.)

There is a competition within and between species. __ – Animals that feed on other living animals (by

killing them first) Ex) Owls, Hawks

Prey – The animals that are killed or eaten Ex) __

Hawks and Owls are in competition for the same prey __reduces the competition.

Relationships in Ecosystem (cont.) B. __

Organisms that cooperate in their life activities may __ each other’s survival

__ animals – members of the same species that live together in colonies and help one another Ex) __

Symbiosis – when two different types of organisms (different species) __ These relationships help maintain survival in many

species

Three Kinds of Symbiosis 1) Mutualism – A relationship in which both species

__ Ex) Ants and acacia trees

2) Commensalism – A relationship in which one species is __. Ex) Spanish moss growing from limbs of trees

3) Parasitism – A relationship in which a member of one species derives __ at the __ of another species Ex) Ticks on a dog

How organisms obtain energy The producers: __

Organisms that use __ energy or energy stored in chemical compounds to make energy-rich compounds.

Ex) __ Other organisms in the biosphere depend on

autotrophs for nutrients and energy (__)

The consumers: __ An organism that __ make its own food and feeds

on other organisms. Types:

__- A heterotroph that feeds only on plants Ex) rabbits, grasshoppers, elephants, etc…

__- Heterotrophs that eat other heterotrophs Ex) lions

__- Organisms that eat a variety of foods that include animal and plant materials Ex) Humans, raccoons, opossums, bears

Types: (cont.) __- Organisms that eat animals that have already died.

(They do __ kill for food) Ex) Black vultures, buzzards, ants, beetles

__- Break down dead and decaying plants and animals and release nutrients Ex) Some protozoan’s, many bacteria, and most fungi

Food Chain Model that shows how __ move through an

ecosystem. Nutrients and energy move from autotrophs to __

and eventually to __ Most consists of two, three or four transfers Only a __ portion of energy remains in the final

transfer as compared to what was in the original A portion of the energy is given off as __

Example of a Food Chain Berries (__)

Field mouse (1st order __) Cat (2nd order __)

Coyote (3rd order __) Crow (__) Bacteria (__)

Food Web Shows __ the possible feeding relationships at

each level in a community Better than a food chain because organisms

__

Ecological Pyramid Shows how __ flows within an ecosystem Base of the pyramid represents __ Higher levels are layered on top of one

another The total energy transfer from one trophic

level to the next is only about __ Why? When an organism consumes food, it uses

some of the energy for __ and the rest is given off as __

How fast do populations grow?

Resembles a “__” curve Exponential growth – as the population gets

larger, it also grows at a __ rate Initial increase is __ because the number of

reproducing individuals is small Rate of population growth soon increases

because the total number of individuals that are able to reproduce has increased.

Population growth does have__

What limits growth? 1) __ 2) __ 3) __ 4) __, etc…(Table 3.1) __– Any biotic or abiotic factor that restricts the

existence, numbers, reproduction, or distribution of organisms Ex) Timberline

Population growth will stabilize in an __-shaped growth curve

Carrying capacity The number of organisms of __ species that

an environment can support __ When a population rises above the carrying

capacity, more organisms __ Limiting factors become an issue The population drops below the carrying capacity

The population will then __ below the carrying capacity (Fluctuates) Figure 4.4

Reproductive Patterns Life-history pattern – __

1. Rapid life-history patterns Common among organisms from __ environments Characteristics: __ body, mature __, reproduce

early, __ life span Populations increase __, then decline when

environmental conditions become unsuitable, then rapidly increase again

Ex) mosquitoes, wild mustard plants

Reproductive Patterns (cont.) 2. Slow life- history patterns

Organisms live in more __ environments Characteristics: __ species, reproduce and mature __,

and are __-lived They __ population sizes at or near carrying capacity Ex) Elephants, bears, whales, humans, trees

Reproductive Patterns (cont.) 3. Density factors – how organisms are __;

random (dandelions), clumped (mushrooms), and uniform (evergreens) *is a __ a) Density-dependent factors – these factors have an

increasing effect as the __ increases Includes disease, competition, predators, parasites, and food Ex) corn crop, HIV/AIDS

b) Density-independent factors – affect populations, regardless of their __ (usually __ factors) Includes temp., pesticides, floods, drought, volcanoes, etc… Ex) insects, earthworms

Predation and Population Size Populations of predators and their prey

experience changes in their numbers over periods of time

Is usually a predictable cycle Ex) Canadian lynx and the Snowshoe hare

The two populations rise and fall close to a 10 year cycle

In prey populations the young, old, or injured members are caught.

Effects of crowding and stress When populations become crowded

(overpopulated): 1. Environments cannot support increased

numbers 2. Animals exhibit various stress symptoms

a. aggression b. decrease in parental care c. decreased fertility d. Resistance to disease

Can have a negative effect on a population

Human Population Census taken every 10 years Demography – study of human population size,

density and distribution movement, and its birth and death rates

History: Before 1800’s – growth was slow (1st billion reached in

1800 Since 1930 – population grew rapidly 1999 – reached 6 billion 2002 – population growing at a rate of 1.3 million people

per year Estimate by 2050 – more than 9 billion people on Earth

Human Population (cont.) Human population is different than other organisms

because humans can consciously change their environment Ex) Eliminated diseases like small pox Ex) Developed methods for producing more food Ex) Infant mortality rate has decreased Ex) Improved the delivery of clean water

Results in people living longer and able to produce offspring that live to produce offspring

Calculating Growth Rate Four factors:

A. __ B. __ C. __ D. __

Formula: (Birthrate +Immigration rate) – (Death rate +

Emigration rate) = Population Growth Rate (__)

Growth Rate (cont.) Doubling time – the time needed for a __ to

double in size Developed country – has a __ growth rate Developing country – has a __ doubling time

__ – the proportions of the population that are in different age levels Rapidly growing countries have age structures

with a __ base (many children and teenagers) Stable populations occur when the % of people in

each age category is fairly __

Natural Resources

Those parts of the environment that are useful or necessary for __

Can be classified into two types: A) __ B) __

Renewable Resources

Those resources that can be __ when they are used

Examples: __, __, wildlife and fish, forests, and air

A renewable resource is not necessarily __ Ex) Fresh water can become limited by drought

or overuse

Nonrenewable Resources Resources that __ be replenished by natural

processes Sometimes called “__” resources Examples: coal, __, natural gas, and minerals

like iron, zinc, copper and lead __ formed millions of years ago from deeply

buried organic materials. When they are depleted they are gone forever

Sustainable Use Is a way of using natural resources at a rate

that __ __ activities affect the supply and the quality

of renewable resources These principles are applied to agriculture,

fisheries, land development etc… Ex) Use of __ instead of pesticides

Pollution The result of substances that __(becomes

unclean usually by contamination of man-made waste)

Air, water, soil, are damaged by pollution Pollutants (materials that pollute) can be

serious such as __, __ released by nuclear accidents, __, and __

Habitat Degradation – damage to a habitat by __ Three types: water, land and air

Water Pollution Degrades aquatic __ in streams, rivers, lakes and

oceans Ex) Excess __ and animal __ are often carried by

rain into streams and lakes These sudden nutrients cause __ blooms. When they die,

they sink and decay, removing needed __ from the water Ex) __ form eroded soils can enter water and clog

the gills of fish Ex) Detergents, heavy metals, industrial chemicals

in runoff cause death in aquatic organisms

Land Pollution __: made up of cans, bottles, paper, plastic,

metals, dirt, and spoiled food that people throw away each day

Average American produces about __ kg of daily (657 kg of waste/person /year)

Some decomposes __ Most becomes buried in __ (meant to reduce

contamination of groundwater supplies) Use of pesticides and other chemical can lead

to habitat degradation

Air Pollution Causes __ problems and irritates membranes

in the eye and nose Sources: Volcanic eruptions, forest fires,

burning of __ Ex) sulfur dioxide – from __ burning factories

and nitrogen oxide from __ exhaust combine to form acid precipitation. This take __ from the soil

__ waves from the Sun can cause damage to living organisms

Methods Used to Reduce Pollution 1. __ – large earthen pit for waste disposal

Either have a high __ content to keep wastes from seeping into underground water or have large __ liners

About __ of waste in US is disposed of in landfills

2. __ – Act of recovering and reusing materials

Ex) paper, aluminum, tin cans, glass, motor oil, auto batteries, auto tires, old cars

Just about anything can be recycled some way

Methods (cont.) 3. __

Laws impose strict standards for what can be released into the environment Ex) __ required to have a catalytic converter Ex) __ (1990) Requires power plants to install

scrubbers on all their smokestacks

4. International agreement to stop __ (chlorofluorocarbons) production Used as __ in refrigerators and air conditioners,

as aerosol propellants etc… Primary cause of __ hole

Methods (cont.) 5. Incinerating – __

They are equipped to prevent releasing harmful __ into the air

Pollution control devices catch __ materials Without this, smoke containing __ are released

into the air. They then settle to the earth and harm plants, animal, and structure (paint on buildings)

Only __ of waste in the U.S. are incinerated