Prentice Hall
Chapter 21
LIVING THINGS AND THE ENVIRONMENT
DEFINE HABITAT.
INCLUDE THREE BASIC THINGS
ORGANISMS GET FROM THEIR HABITAT AND TELL
WHY THEY NEED THOSE THINGS.

Habitat: the environment (forest, grassland,
desert, tundra, etc.) where living things
obtain what they need to live, grow, and
reproduce.
 BASICS:
1. food to live & grow
2. water to live & grow
3. shelter to live and reproduce
DEFINE BIOTIC FACTORS AND DESCRIBE
THE BIOTIC FACTORS FOUND IN THE HABITAT OF
A PRAIRIE DOG.
The living parts of a habitat – the organisms,
populations, and communities.
 In a prairie grassland, this includes grass
and other plants; seeds and berries; hawks,
ferrets, sage grouse, bison, rattlesnakes,
badgers, and eagles.
 Worms, fungi, and bacteria are also biotic
factors found in the prairie dog habitat.

LIST AND DESCRIBE THE FIVE MAIN
ABIOTIC FACTORS OF AN ECOSYSTEM.

WATER makes up 65% of the bodies of most organisms and is

SUNLIGHT provides the energy for photosynthesis, and therefore

OXYGEN is required by most living things to carry out life

TEMPERATURE has a major impact on ecosystems.

SOIL is a mixture of rock fragments, nutrients, air, water, and the
needed to carry out life processes including photosynthesis and
cellular respiration.
helps begin most food chains
processes. For land animals, it is obtained from the air which is
about 20% O2. Aquatic organisms require dissolved oxygen.
The
degree of heat or cold partly determines which plants and animals
can survive in an area.
decaying remains of living things- along with bacteria and fungi.
The type of soil largely determines which plants can grow in an area.
SUMMARIZE THE TWO PARTS OF EVERY
ENVIRONMENT:
1. BIOTIC: all the LIVING factors in an
environment
2. ABIOTIC: all the NON-LIVING factors in an
environment (physical factors - such as water,
soil, light, and temperature that affect
organisms living in a particular area)
HOW IS AN ENVIRONMENT ORGANIZED?
WHAT ARE THE LEVELS OF ORGANIZATION?
ORGANISMS- Individual living things
POPULATIONS – same species living together in the same place at the
same time
COMMUNITY – all the Living populations in a region
ECOSYSTEM – living communities along with their non-living (abiotic)
surroundings
BIOME – group of land ecosystems with similar climate and organisms.
Ex.: Rainforest, Desert, Prairie, Deciduous Forest, Tundra. See p. 758.
BIOSPHERE - the global sum of all ecosystems.
It can also be called the ZONE of LIFE on EARTH
* 1-3 are strictly BIOTIC; Interactions between biotic and abiotic components occur at levels 4-6 of an environment
HOW ARE THE LEVELS OF THE ENVIRONMENT
CONNECTED?
As we move to higher levels of organization,
the levels include more and more living
things, types of habitats, and complexity.
DEFINE POPULATION:

A population is a group of individuals of the
same species that live together in the same
area at the same time.

Examples: a population of Great Horned Owls,
prairie dogs, sage grouse, bison, etc.
DEFINE COMMUNITY:
Consists of all the populations of different
species (plants, animals, protists, bacteria,
fungi) that live and interact in an area
DEFINE ECOSYSTEM:
Is made up of a community of organisms along
with abiotic factors
DEFINE ECOLOGY:
the study of how living things interact with each
other and with their environment
ECOLOGY
LIST AND DESCRIBE FIVE METHODS OF
DETERMINING THE SIZE OF A POPULATION.
1.
Direct Observation: Locate, count, and tally organisms you
2.
Indirect Observation: Calculate numbers by signs of
3.
4.
5.
are studying
organisms, such as nests, tracks, scat (droppings), or sounds
(bird or whale vocalizations)
Sampling: Calculate an estimate based on a sample density
of organisms in a small area (Ex: 1 m2), and multiply times the
number of these units in the study area.
Mark-and-Recapture: Mathematical calculation of
population size based on capturing, marking, and later recapturing organisms
PHOTOGRAPHY: WEB CAMS, MOTION SENSOR REMOTE
CAMERAS (trail cameras), STILL PHOTOS
CHANGES IN POPULATION SIZE

If birth rate
›
(is greater than) death rate,
population size increases.
- ----------------------------------
If death rate
›
(is greater than) birth rate,
population size decreases.
DEFINE IMMIGRATION:

Moving into a population
 Some
Canada geese which used to migrate north
for the summer now stay in locations farther south
year round,
 And additional former migrants might immigrate to
join these local populations
DEFINE EMIGRATION:
Leaving a population
 If food is scarce, members of an antelope herd
may wander off in search of better grassland
for grazing. If they are permanently separated
from the original herd, they will no longer be
members of that population. They will have
emigrated to a new territory.

DEFINE POPULATION DENSITY AND INCLUDE
THE EQUATION TO ILLUSTRATE.
Number of individuals of a species in a given area:
POPULATION
DENSITY

=
NUMBER OF INDIVIDUALS
UNIT AREA
Example: If you counted 20 monarch butterflies in a
garden measuring 10 square meters, the population
density would be 20 monarchs per 10 m 2 ,
or
2 per sq. meter.
DEFINE LIMITING FACTORS AND DESCRIBE FIVE
EXAMPLES.


Definition: environmental factors that cause a population to decrease; any needed
resources that can become scarce and result in competition
–OR- abiotic conditions that can influence the size of a population
------------------------------------------------------------------
1.
FOOD- Lack of food could mean starvation for some
2.
WATER- Dehydration is deadly!
3.
LIVING SPACE – Loss or reduction of space or territory makes it less likely that organisms
will reproduce
4. WEATHER – Extremes of temperatures can be deadly, and floods can wash away nests and burrows.
5. HUMANS often impact animal and plant populations. When humans develop land for houses and
buildings, they cut down trees and change animal and plant habitats. Some animals, like the raccoon
and the skunk, can adapt, but other animals can't adapt and their populations are affected.
6. COMPETITION for resources, PREDATION, or DISEASES
EXPLAIN CARRYING CAPACITY:
the largest population an area can
sustain over a long period of time
NATURAL SELECTION
ANY CHARACTERISTIC
THAT MAKES AN
INDIVIDUAL BETTER
SUITED TO ITS
ENVIRONMENT MAY
EVENTUALLY BECOME
A COMMON TRAIT
THROUGH THIS
PROCESS.
NICHE – is the role of an organism in its
habitat, or how it makes its “living,”
– this includes the type of food it eats, how it
obtains the food, and which other organisms
use it as food- is its . . .
A niche is the role of a particular species -what it does -- within its habitat. No two
species perform precisely the same role in a
particular habitat, at least not for long. If they
do, competition for food and a place to live
results, and one species eventually excludes
the other.
EXPLAIN HOW THREE DIFFERENT SPECIES OF WARBLERS CAN
HAVE 3 DIFFERENT NICHES ALL IN ONE TREE.
By feeding in different areas of a spruce tree,
the birds avoid competing for food.



The Cape May Warbler feeds at the top;
the Bay-Breasted Warbler feeds in the middle;
the Yellow-Rumped Warbler feeds in the lower part and the bases of the
middle branches.
DEFINE COMPETITION.
INCLUDE EXAMPLES OF COMPETITION FOR FOOD, WATER, SHELTER, SPACE, OR SUNLIGHT.

One of the three major types of interactions among living
things,
competition is the struggle between organisms to
survive as they attempt to use the same limited
resource.
DEFINE PREDATION. INCLUDE “PREY” IN YOUR
EXPLANATION.

interaction in which one organism (the
predator) kills another for food (the prey)
HOW DOES PREDATION AFFECT POPULATION SIZES?




Populations of predators and prey rise and fall in
related cycles.
Too many predators = drop in prey populations.
Lack of food then causes predators to decline.
Too few predators = increase of prey populations.
LIST AND ILLUSTRATE EFFECTIVE ADAPTATIONS
USED BY PREDATORS AS STRATEGIES TO
LOCATE &/OR KILL PREY.







Speed – to out-run, out-swim, or out-fly prey
(cheetah)
Poison – to stun, immobilize, or kill prey
Sticky substances to snare insects
Light-sensitive eyes that see well in low light (owls)
Echolocation: Bats, whales, & dolphins use sound
waves to pinpoint location of prey
Camouflage to avoid being noticed by prey
Group cooperation for hunting
LIST AND ILLUSTRATE EFFECTIVE
ADAPTATIONS USED BY PREY ANIMALS AS
DEFENSE STRATEGIES.
Speed
 Poisons (stinging tentacles of jellyfish)
 Offensive smells (skunk spray)
 Mimicry – caterpillar that looks like viper
 False coloring – False eyespots on wings of
moth
 Protective covering – pangolins, armadillos
 Camouflage – walking leaf insect
 Warning coloration – the bright colors of
certain insects, reptiles, and amphibians
warn that they are poisonous

DEFINE SYMBIOSIS:

A very close long-term association between two or
more species. Thousands of these relationships
are found in nature and they are classified
according to the impact the association has on
the species involved.
DEFINE
MUTUALISM,
COMMENSALISM
& PARASITISM IN
THE SPACE
PROVIDED ON THE
CHART.
MARK A “+” “-“ OR “0”
IN EACH SPACE UNDER
THE HEADINGS FOR
SPECIES A AND
SPECIES B TO
INDICATE HOW EACH
IS AFFECTED.
NEXT, PROVIDE
CLEAR
EXAMPLES FOR
EACH OF THE THREE
TYPES OF
SYMBIOSIS.
THREE TYPES OF SYMBIOSIS
RELATIONSHIP DEFINITION -
TYPE OF SYMBIOSIS
Mutualism
:
both species benefit
Commensalism:
SPECIES
A
“
”
SPECIES “
B”
& EXAMPLES
& EXAMPLES
+
Saguaro
Cactus
gets pollinated
+
Long-eared bat
Gets food
+
0
one species benefits; the 2nd
Red-tailed hawk
species is neither helped nor Gets good nest site
harmed
in region without
trees
Saguaro
Cactus
Not affected
Parasitism:
+
-
the parasite benefits
and the host is
harmed
(parasite)
(host)
Tapeworm or tick
Gets food
Dog or human
Is weakened or
made sick
DEFINE SUCCESSION:

(NATURAL SUCCESSION)
the series of predictable changes in vegetation
that occur in a natural community over time
DEFINE

PRIMARY SUCCESSION
Primary succession is the slow series of
changes in plant life that occurs in areas
where . . . no soil or organisms are present,
such as a new island formed by the eruption of
an undersea volcano or an area of rock
uncovered by a melting sheet of ice (retreating
glacier).
DESCRIBE AND ILLUSTRATE THE STAGES OF
PRIMARY SUCCESSION.
WHAT ARE PIONEER SPECIES AND HOW
DO THEY ARRIVE AT THE LOCATIONS THEY
COLONIZE?
Pioneer species are the first organisms to
populate a bare area.
 They are often carried by wind or water.
 Lichens and mosses are often among the
first to colonize

WHAT ARE LICHENS ?
AND HOW DO THEY MANAGE TO LIVE ON THE SURFACE OF
ROCKS?



Lichens are a
combination of fungi
and algae growing in a
symbiotic partnership.
The fungal part
dissolves the minerals
on rocks to extract
nutrients.
The algal part
photosynthesizes to
make food for the
lichen.
Observe LICHENS at stereoscope and
make a detailed, colored drawing ABOVE
at 10x or 20x magnification.
EVENTUALLY, SUCCESSION MAY LEAD TO
A STABLE COMMUNITY THAT DOES NOT
CHANGE SIGNIFICANTLY UNLESS . . .

the ecosystem is disturbed
(by nature or by human actions)
WITH PRIMARY SUCCESSION, HOW LONG
MIGHT IT TAKE TO REACH A CLIMAX
COMMUNITY OF ORGANISMS GROWING IN
FERTILE SOIL WITH MATURE PLANTS?

It can take centuries to mature to this state—
often called a climax community!
DEFINE SECONDARY SUCCESSION:

The series of changes that occur in an area
after the ecosystem has been disturbed.

Unlike primary succession, secondary
succession occurs in a place where an
ecosystem currently exists.
DESCRIBE EXAMPLES OF NATURAL
EVENTS THAT MAY DISTURB AN
ESTABLISHED COMMUNITY AND LEAD
TO SECONDARY SUCCESSION.
Fires caused by lightning,
 hurricanes,
 tornadoes,
 floods,
 mudslides,
 tsunamis,
 earthquakes

WHAT KINDS OF HUMAN ACTIVITIES CAN
DISTURB AND ALTER ECOSYSTEMS?

Human activities such as
 farming,
 housing
development,
 clear-cut logging,
 strip-mining ,
 mountain top removal mining–
 or even abandoning fields that were once
cultivated –

can set the stage for secondary succession.
DESCRIBE SECONDARY SUCCESSION.
INCLUDE
DIAGRAMS, EXPLANATIONS, AND EXAMPLES AT EACH STAGE.
WHAT TWO “INGREDIENTS” ARE NECESSARY
FOR SECONDARY SUCCESSION TO OCCUR?
1.
SoiL
2.
Organisms