Transcript Ecology Unit - Midwest Central CUSD #191 / Homepage

Ecology Unit
2.1 Organisms & Their Environment

Ecology

What does –ology mean on the end of any
word?
The study of

What word does eco- remind you of?
Ecosystem
Definition:
Ecology is the study of how organisms interact
with each other and their environment.

The environment has abiotic and biotic
factors.
Remember:
The prefix a- in front of any word
means no or not.
The prefix bio- mean life or living
Definitions:
Abiotic factors – nonliving things in the
environment.
Biotic factors – living things in the
environment.
Label the following items as biotic
or abiotic.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Air
Cat
Temperature
Moisture
Plant
Mushroom
Light
Soil
Water
Seeds
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Abiotic
Biotic
Abiotic
Abiotic
Biotic
Biotic
Abiotic
Abiotic
Abiotic
Biotic
Circle the biotic factor(s) and
underline the abiotic factor(s) in
the following studies:


Example #1 – Study of the life cycle of
trout to observe whether they need to lay
their eggs on rocky bottomed streams or
sandy bottom streams.
Example #2 – Study of moles and observe
which soil types the animals prefer to dig
their tunnels in.
Levels of Organization
(smallest to largest)
1. Organism – an individual living thing
2. Population – a group of organism (all of
one species) that breed with each other &
live in the same place.
3. Community (or Biological Community) – all
populations of different species that live in
the same place.
4. Ecosystem – all the biotic & abitoic factors that
interact with each other in a given area.
Two major types of ecosystems:
1.
Terrestrial – ecosystems located on land
2.
Aquatic - ecosystems located in fresh or salt water
Definitions:
Habitat – a place where an organism lives its life
- can change or disappear
- example: a tree, ocean, soil, pond
Niche (neesh) – how organisms interact with their
biotic and abiotic parts of the habitat
It is an advantage for a species to occupy a
niche different from other species in the
same habitat.
Two species can’t exist for long in the same
community of their niches are the same
(leads to competition & reduces resources
such as food).
5. Biosphere – the portion of Earth that
supports life
www.chesterfield.k12.sc.us/.../BiologyICP.htmlRemove frame
www.ux1.eiu.edu/~cfruf/bio3002/levels_ecology.htm
video
Do all organisms get along with
each other?


How organisms live together in an
ecosystem is called symbiosis.
There are 3 types of symbiosis:
1.
2.
3.
Mutualism
Commensalism
Parasitism
Mutualism


Both species benefit from each other.
Example – ants and acacia trees

Ants protect the acacia tree from other
animals that might eat the tree. The tree
provides nectar and a home for the ant. They
both benefit from each other!
Commensalism


One species benefits
and the other species
is neither harmed nor
benefited.
Example – Spanish
moss growing on trees

Spanish moss has a
place to live on the
trees but the trees are
not harmed by the
moss or get nutrients
from the moss. Only
one benefits and the
other does not.
Parasitism



One species benefits at the expense of another
species.
Parasites usually don’t kill their host (the animal
they live on). Why would you kill the person
that is providing you food & a home???
Example – ticks on a dog


Tick is a parasite that feeds off the nutrients in the
dog’s blood. The dog doesn’t get the nutrients so it is
harmed.
Tapeworm & roundworms work the same way as tick
but they are inside the host’s body.
Predator – Prey relationship

Predator – found in all ecosystems and eat
plants and/or animals. Predators are a
type of consumer that seek out and eat
other organisms.
Prey – the animal that the predator eats.

Example – cat & mouse; lion & antelope

Section 2.2 Nutrition & Energy Flow
In order to be living, one of the
characteristics of life is to use energy.
How is that energy obtained by
organisms? It varies on the organism.

Autotrophs – make their own food


Autotrophs are called producers. Think about
the definition! Autotrophs produce their own
food so called producers.
Example – grass, trees, green algae which is a
unicellular organism

Heterotroph – can not make their own
food; instead have to eat food to get
energy.


Heterotrophs are called consumers. Think
about the definition! Heterotrophs consume
food so called consumers.
Example – deer eating leaves; bison eats
grass; owl eats a mouse
Heterotroph Relationships:
1.
Herbivore – consumers (heterotrophs) that
eat producers (autotrophs)
Example – rabbits, grasshoppers, beavers,
squirrels, bees, elephants, bats
2. Carnivores – consumers (heterotrophs) eat
consumers (heterotrophs)
Example – lion kills another lion
3. Omnivores – consumers (heterotrophs) that
eat a variety of foods (plant or animal)
Example – raccoons, opossum, bears, humans
4. Others
Scavengers – do not kill for food; eat
animals that are already dead
Example - vultures
Decomposers – break down dead
decaying plants and animals.
Example – bacteria & fungi
Flow of Matter & Energy


Food Chain is a simple model that shows
how matter & energy moves through an
ecosystem.
Arrows indicate the direction in which
energy is transferred from one organism
to the next.
Example –
Berries (autotroph) Mice (first order
heterotroph)  Hawk (second order
heterotroph
http://www.umaine.edu/
umext/earthconnections/
images/foodchain.gif
http://kentsimmons.uwin
nipeg.ca/16cm05/1116/5
3-10-FoodChains-L.jpg
http://www.bcgrasslands.org/SiteCM/i/upload/4D9BB688
B89B4092F9D10BDAEF83EC41E762FBDB.jpg

Trophic level – a feeding step in the
passage of energy & materials


First order heterotroph – organism that feeds
on plants
Second order heterotroph – organism that
feeds on a first order heterotroph
http://www.utc.edu/Faculty/
DeborahMcAllister/educ575/wq04Mic
haelKavur/image002.jpg
http://www.mlms.loga
n.k12.ut.us/~mlowe/E
nergyPyramid.gif




Food webs – show many food chains that
can occur in a community.
Ecological pyramids show how energy
flows through an ecosystem in a pyramid
form.
Base is always the autotrophs (first trophic
level).
Next layers build upon each layer for
higher trophic levels.
http://cmore.soest.hawaii.edu/cruises/operex
/images/terrestrial_food_web_full.jpg
3.1 Communities


Various combinations of abiotic and biotic
factors interact in different places around
the world which results in conditions in
one part of the world are suitable or
certain life and not others.
Limiting factors – any biotic or abiotic
factor that restricts (or limits) the
existence, numbers, reproduction, or
distribution, or distribution of organisms.

Examples of limiting factors:



Availability of water & food would affect how
many, if any, organisms can live in an area
Predators to an area would affect the number
of organisms (prey) living in the area
Temperature of the area affect which animals
live there (polar bear will not be in a desert)
List of common limiting factors: amount of
sunlight, climate, temperature, water,
nutrients/food, fire, soil, chemistry, space,
other organisms



Factors that limit one population in a
community may also have an indirect
effect on another population.
Example – lack of water limits the growth
of grass  lack of grass limits the seeds
produced  lack of seeds limits the
mouse population  lack of mice limits
the hawk population
Tolerance – ability of an organism to
withstand many biotic and abiotic factors.

Different species have different ranges of
tolerance
video
Succession

Natural changes & species replacements
that take place in the community of an
ecosystem.




Occurs in stages and at each stage different
species of plants and animals may be present
At each stage of succession, new organisms
may move in, others may die or move out
Difficult to observe because takes decades or
more to go to the next stage
Two types of succession: Primary & Secondary
Primary Succession

Colonization of barren land by communities
of organisms.


Takes place in land where nothing lived before
Example – after a volcano
First species to grow in the area are called
pioneer species
LICHENS
Example - lichens
http://botit.bo
tany.wisc.edu
/images/332/
Lichens/Folios
e_lichens_130
_d.gif



Pioneer species eventually die making the
first stage of soil for other organisms to live
Example – small ferns, fungi, & insects
These organisms die & more soil builds.
Seeds carried or blown in will start to grow
After time, the are will become more stable.
A stable, mature community that undergoes
little or no change is called a climax
community.


Can last 100’s of years
Change DOES occur in a community but
changes are balanced.
http://www.life.illinois.edu/bio100/l
ectures/s97lects/05Succession/rock
Succession.GIF
Volcanic Eruption
Primary Succession
Secondary Succession
http://tinyurl.com/y95bfk9
Secondary Succession

The sequence of changes that takes place
after an existing community is severely
disrupted in some way
Example – forest fire, field is not replanted,
tear down a building and leave it


Are gradually changed over time
Soil already exists in a secondary succession so
takes less time than primary succession to
reach a climax community.
http://www.ck12.org/ck1
2/images?id=113572
Years after a forest fire.
Stages of
secondary
successsion
http://images.google.com/imgres?imgurl=http://biology.clc.uc.edu/graphics/bio303/w
etland.jpg&imgrefurl=http://biology.clc.uc.edu/Courses/bio303/succession.htm&usg=
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%2Bsecondary%2Bsuccession%26gbv%3D2%26hl%3Den
Chapter 4 Population Biology
Section 4.1 Population Dynamics
Principles of Population Growth
 Populations typically form a “J” shape curve
http://p
eer.tam
u.edu/cu
rriculum
_module
s/ecosys
tems/im
ages/ex
ponentia
l.jpg
This “J” shaped curve
is called Exponential
Growth – means that
as a population gets
larger, it also grows at
a faster rate.



Initial increase in the number of organisms
is slow because of the number of
reproducing organisms is small.
Rate of growth will increase because
number of individuals able to reproduce
has increased.
Can a population grow indefinitely
(meaning forever)? NO

Populations have limiting factors!
See Chapt. 3 for the list of limiting factors.
Because of these limiting factors the
population may form an “S” shape growth
curve.
Carrying
capacity –
number of
organisms of
one species
that an
environment
can support
indefinitely
(forever).
http://www.saburchill.com/IBbiology/images/140106009.jpg
Questions
1.
2.
3.
4.
5.
What happens to a population when there are
more births than deaths?
What happens to a population when there are
more deaths than births?
What happens to a population when the
number of deaths equal (or close to equal) the
number of births?
When the population overshoots the carrying
capacity, the ________ take over to bring the
population into check.
Why can a population fluctuate (go up and
down) once it reaches carrying capacity?
Answers
1.
2.
3.
4.
5.
Increases
Decreases
Stays the same
Limiting factors
The population can go up and the
limiting factors take over and bring it
back down into check. The population
can go down and the amount of
resources (food) goes up and the
population will go up.
Reproduction Patterns

Life–history pattern – an organism’s
reproductive pattern


Can be studied by population biologists to
determine if carrying capacity has been reached
Two types of reproductive patterns:
Rapid life history pattern
 Slow life history pattern

Rapid Life History Pattern


Meaning the organism can reproduce rapidly
Typically increase rapidly & then declines when
environmental conditions change
Example-mosquitoes grow and reproduce
quickly in the summer but not in the winter.

Usually have:




Small body size
Mature rapidly
Reproduce early
Have a short life span
Slow Life History Pattern

Meaning the organism reproduces slowly



Typically live in a more stable environment
Opposite of all the things listed in rapid life
history patterns
Maintain population sizes at or near carrying
capacity

Example – elephants, bears, whales, humans
3 Ways Organisms Are Dispersed
1. Random – often seen (ex. Dandelions)
2. Clumped – most common
3. Uniform – least common (visible with
birds on a wire)
Uniform
There are 2 kinds of limiting factors when it comes
to dispersal:
Density-dependent factors – include disease,
competition, predators, parasites, & food
-these factors have an increasing effect as
the population increases
Density-Independent factors – mostly abiotic
factors like volcanic eruptions, temperature,
storms, floods, droughts
-all populations can be affected by these
factors, small organisms are most vulnerable
What can limit a population size?
1 – Predation affects population size.


If number of predators decrease then the
number of prey increases
If number of prey increases then the number
of predators will increase over time & then
eventually will decrease because to many
predators for the amount of food available.
What can limit a population size?
2 – Competition within a population


When resources (food, water, shelter) are
plentiful, the population will increase
But when resources are not plentiful,
competition will occur or those resources &
the population will decrease
What can limit a population size?
3 – The effects of crowding & stress


Some organisms will show symptoms of stress
when in crowded situations
Increase in population can cause stress
symptoms such as: aggression, decrease in
parental care, decreased fertility, & decreased
resistance to disease which can lead to a
decrease in population