unit 2: ecology chapters 2-5. what is ecology? a branch of __ that studies the interactions that...
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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