Post on 11-Mar-2020
• Each organism in an ecosystem needs a place to live called habitat.
1
• The habitat provides everything an organism needs to SURVIVE AND REPRODUCE:
• Food, water
• Shelter
• Adequate temperature and humidity
Habitats
Organisms are not alone
An ecosystem consists of all the
organisms living in an area, as well as the
nonliving parts of that environment.
Different types of organisms living in the
same area will interact.
• One of the most important aspects related to the interaction among organisms is called
COMPETITION
Competition occurs when two organisms seek the same resource at the same time.
2
Populations
Competition will:
1) Decrease an organism’s chance of survival
2) Limit population growth
2
Populations
• In nature, the most intense competition
is usually among individuals of the
same species, because they need the
same kinds of resources.
1) What do organisms living in the same
area will compete for?
Food, space, water, light (plants),
organisms of the same species to mate
2) What is population density? Book page
99 – Population size
It is the number of individuals of one species
Per a specific area
3) Why is it important to measure the
size of different populations on a given
environment?
-To make sure the species is not in danger
of disappearing of that area
-To determine hunting seasons
-To determine how many organisms can be
removed from the ecosystem
- The size of this organisms Ex. Crabs
4) What methods can be used to measure
population size?
2 methods that are widely used:
First method :
Sample Counts – Read page 100
Figure 7
Sample Counts
EX: A biologist collected 1 gallon of pond
water and counted 50 paramecium
(unicellular organisms).
Based on the sampling technique, how many
paramecium could be found in the pond if the
pond were 1,000 gallons?
50 x 1000 = 50,000
**Problem with the Sample Count
Technique
- different areas might have more dense
populations
if you took a sample from the bottom of
the lake it may be different from a sample
at the top of the lake
Measuring Population Size
Second method:
Trap, Mark and Release or Mark and Capture
- estimates the number of organisms in a
population
**This technique is commonly used by fish
and wildlife managers to estimate
population sizes before
fishing or hunting seasons.
worksheet
Problems with the Mark- Release
Technique
• Make sure:
• There is no immigration or emigration
• Animals are mixing with the rest of the
population in between samplings
• Mark them well or they will loose the
mark
• The period of time in between samplings
have to be smaller than the life span
Aspects that affect the size of a
population
• Birth rates and death rates
• Immigration and Emigration ( organisms
can be carried by wind, water, or just
move on their own)
• Limiting factors
Important terms
• Find the definitions of:
• Limiting factor
• Carrying capacity
• Biotic Potential
Limiting Factors – living or non living
2
Populations
• A limiting factor is anything that restricts the number of individuals in a population.
Ex: availability of food, water, living space, mates, nesting sites ( shelter), light (plants), predators
• A limiting factor can affect more than one population in a community, at the same time
• Ex: Lack of water ,will affect different populations
• lack of light for plants
2
Populations
Limiting Factors
Visualizing the effect of a limiting factor in a population
• Worksheet to turn in – graph paper and ruler
• The Lynx – Hare relationship over the years reflect how the predator /prey interaction of two species affects population size.
2 Limiting Factors
• The lynx eats the hare – so if there are
not enough hares, the number of lynx
will decrease. The number of hares
limits the lynx population.
• The hare is killed by the lynx, so if there
are few lynx, the population of hares will
increase.
• is the largest number of individuals of one species that an ecosystem can support over time.
Carrying Capacity of an Ecossystem 2
• If a population begins to exceed the environment’s carrying capacity, some individuals will not have enough resources and competition will increase.
• die
• move elsewhere.
• It is the highest rate of reproduction in a population, under ideal conditions
• Ideal Conditions would be:
No diseases
No predators,
Enough food, water and space ( no competition)
Biotic Potential 2
• When a species moves into a new area with plenty of food, living space, and other resources, the population grows quickly, in a pattern called exponential growth.
• Exponential growth means that the larger a population gets, the faster it grows.
Exponential Growth 2
Populations
2
Populations
• Over time, the population will reach the ecosystem’s carrying capacity for that species and will stop the exponential growth .
Exponential Growth
Section 3
• Interactions within Communities – about
feeding patterns within a community and
how the energy moves from one
organism to another
Guided reading
1) Organisms obtain energy by the
process of photosynthesis or cellular
respiration. Define:
1a)Producers
1b)Consumers
Explain which one uses photosynthesis
and which one uses cellular respiration
and why.
• 2) Explain the difference between the 4
types of consumers.
• 3) what is a food chain and what is food
web – see Glossary
• 4) What is symbiosis? List 3 types of
symbiosis and explain.
• 5) what is niche?
• 6) Why does each species have its own
niche, and why is this important in an
ecosystem?
• 7) Explain why a predator-prey relationship
can be important in an ecosystem.
• 8) Why is cooperation among organisms
important?
• Living organisms need a constant supply of energy to survive. There are 3 types of processes used by organisms to obtain E.
1 - Obtaining Energy 3
1) Photosynthesis
2) Chemosynthesis
3) cellular respiration
1) Organisms obtain energy by the
process of photosynthesis or cellular
respiration. Define:
1a)Producers
1b)Consumers
Explain which one uses photosynthesis
and which one uses cellular respiration
and why.
• Organisms that use an outside energy source like the Sun to make energy-rich molecules
1a- Producers: 3
• Green plants are producers
• they have chlorophyll and will transform water and carbon dioxide into sugars, in the presence of light.
• The process is called photosynthesis
Chemosynthesis – another chemical
process used by organisms to produce
energy rich nutrients.
It is used by organisms that do not have
access to light – such as bacteria that live
close to the ocean floor.
Chemosynthesis
These organisms use energy obtained
from chemicals to replace the sunlight
energy used during photosynthesis.
Chemosynthesis is thought to have
been used by the first forms of life on
Earth.
• Organisms that cannot make their own energy-rich molecules because they do not have chlorophyll.
1b - Consumers
Interactions Within Communities
• Consumers obtain energy by eating other organisms ( producers or consumers) and use cellular respiration to break the food and obtain E.
Oxidation = Cellular Respiration
Cellular Respiration is an oxidation process.
It is a chain of chemical reactions that happens
in the presence of Oxygen.
• Herbivores – eat plants
• Carnivores – eat meat
• Omnivores – eat plants and meat
• Decomposers – consume wastes and dead animals
Interactions Within Communities
2 - Consumers: 4 types
3 - Food Chain model that shows the feeding relationships in an ecosystem and the path of the energy .
• For example, shrubs are food for deer, and deer are
The arrow points to the predator
The arrow points to the predator
Food web is a complex model – shows the
connections among different organisms in
different food chains
• 4) What is symbiosis? List 3 types of
symbiosis and explain.
• Mutualism
• Commensalism
• parasitism
4 – Symbiosis 3
• It is the term used to describe any close relationship between species.
• Sometimes one species depend on another to survive
• There are 3:
Lichens – association between
algae and a fungus
3
Cyanobacteria or algae
will produce food for
the fungus
Fungus – provide
shelter
or a place to live to the
cyanobacteria
b) Commensalism - A symbiotic relationship in which one organism benefits and the other is not affected
3
• Anemones and Clown fish
• The anemone’s tentacles protect the clown fish from predators.
Shark and Remora:
Commonly called a
suckerfish, the
remora is a marine
fish that attaches to
the shark and feeds
on sharks left
overs.
c) Parasitism - a symbiotic relationship in
which one organism benefits but the other
is harmed
3
Roundworms
Are parasites that attach to the inside of the intestines of other organisms and feed on these organism’s blood.
• An organism’s niche is its role in its environment:
- how it obtains food
- or shelter,
- or a mate,
- or cares for its young
- what they eat, where they live, etc.
5- Niche
• 6- Why does each species have its own
niche, and why is this important in an
ecosystem?
• The niche of each species that live in the same area is a little different to avoid competition.
• So it is important that different species have different niches
• Examples:
5- Niche
Closely-related species will:
Have different food preferences,
Hunt for food at different times,
Live in different locations within the area
The niches are a little different so the
different species can live in the same
area
• It is important because it allows different species to inhabit the same place, bringing diversity to the area.
7- Predator and Prey
• Importance for the Ecosystem:
• The predator will limit the size of the prey population
• As a result, food and other resources used by the prey will not be scarce
• the population of the prey in that area will remain somehow constant and,
• the predator will be able to continue feeding on the prey
Is a predator and prey relationship
a type of symbiosis?
**Predator – Prey is different than symbiosis because one organism will die for the other to survive .
In symbiosis both will live
• Individual organisms often cooperate in different ways.
• Cooperation improve survival and it is part of a specie’s niche
8- Cooperation
• For example, a white-tailed deer that detects the presence of wolves or coyotes will alert the other deer in the herd.
• Social organization of insects – different tasks
Matter and Energy Flow
In nature, energy and matter are never
lost, they just change from one form to
another and are transferred from one
organism to another.
Food Chains and Food Webs are models
that illustrate these transfers.
Food Chains - is a simple model of
the feeding relationships in an ecosystem.
• It shows how energy is transformed in
nature and how is transferred from one organism to another.
Food Chains
• A food chain always starts with the producers or
autotrophs ( can make its own food – the others are called heterotrophs)
• The second step are the herbivores or primary consumers
• The third step are the secondary consumers that will eat the primary consumers or herbivores.
• The tertiary consumers eat the secondary consumers. They can be carnivores or omnivores.
• Decomposers
•A food chain always starts with the producers or autotrophs ( can make its own food – the others are called heterotrophs)
Decomposers play an important role:
• Decomposers complete the food chain and
will return nutrients from the decomposed dead plant or animal, back to the environment.
Food Web: model that shows the
complex feeding relationships in a
community.
It is complex because it shows how
different food chains are
interconnected.
Different consumers eat diff. types of
foods
Trophic Levels
The position of an organism within a food
chain or food web are called trophic levels.
These levels are divided into:
producers (first trophic level),
consumers (the following trophic levels),
decomposers (last trophic level).
Energy transfer and Energy loss
• Both Food Chain and Food Web show
how energy is transferred from one
trophic level to another.
• IN each one of the trophic levels,
organisms will oxidize their food to
obtain energy to survive.
• From one level to another some
energy is lost to the environment in
the form of heat.
•
Energy Pyramids
• Shows the amount of energy available in
each trophic level.
• The first trophic level is the base of the
pyramid, with more organisms and more
energy available.
Biotic and Abiotic Factors
• Biotic and Abiotic are important parts of
an ecosystem.
• Some abiotic factors are: water,
atmosphere and soil
• They are important because they contain
substances that are indispensable for the
survival of any organism.
Cycles in Nature
• The Earth contains a fixed amount of
water, carbon, nitrogen and oxygen;
materials required for life.
• Theses materials cycle through the
environment and keep on being reused
by different organisms
Oxygen Cycle
In your own words, write a paragraph
describing the Oxygen cycle.
Think about: plants, photosynthesis,
animals, respiration.
Time: 5 min
Oxygen Cycle
• plants ( autotrophs) take in CO2, water
and produce O2 in the presence of sunlight.
• The O2 is released in the atmosphere
• O2 is taken in by heterotrophs during
respiration , transformed in CO2 during
cellular respiration.
• It is released in the atmosphere by the
heterotrophs and absorbed again by
plants.
Nitrogen Cycle
• 78% of the atmosphere is Nitrogen
• But the N2 in the atmosphere can’t be
used by organisms
Organisms can’t absorb nitrogen from the
atmosphere
• Molecules of Nitrogen are two atoms of
nitrogen united by a stable triple bond.
This bond must be broken for the
nitrogen to be used.
• The nitrogen gas must be changed to
nitrogen compounds called nitrates or
ammonia, to be absorbed by organisms.
Nitrogen Cycle-Book page 132
1) Why is Nitrogen important for organisms?
2) Explain Nitrogen Fixation
3) Explain the Nitrogen Cycle or make a
diagram
4) Explain why farmers use fertilizers or
plants with nitrogen fixing bacteria.
5) What type of symbiotic relationship exists
between the bacteria and the roots?
1) Why is Nitrogen important for
organisms?
Proteins and DNA contain N2 and
organisms depend on these two types of
molecules to survive
2)Explain Nitrogen Fixation
- Some bacteria can absorb N2 from the
atmosphere and transform this N2 in the
Nitrogen compounds that can be used by
plants.
- Those are the nitrogen-fixing bacteria
that live inside the roots of some plants and
in the soil
Other important bacteria involved in
the N cycle ( copy)
• Nitrifying bacteria – turn the Nitrogen in
wastes and dead organisms ( ammonia)
into nitrates
• Denitrifying bacteria – turn the nitrates
into N2 ( nitrogen molecules) and return
them to the atmosphere
Nitrogen Cycle
4) Explain why farmers use fertilizers or
plants with nitrogen fixing bacteria.
When soils is over used, the level of
nutrients decrease. To add nutrients to the
soil and make sure the soil is fertile,
farmers use fertilizers, manure, compost or
plant with nitrogen-fixing bacteria
5) What type of symbiotic relationship exists
between the bacteria and the roots?
Mutualism:
It is advantageous for both species.
The bacteria depends on the plant for food
and the plant depends on the bacteria to
obtain N2
Carbon Cycle
• 1) Read page 66 of the textbook and
explain why is carbon important and
where is carbon found in our body.
• 2) Look at the picture on page 134 and
explain what the sources of carbon and
carbon dioxide are.
• 3) Make a drawing or a diagram of the
Carbon Cycle
1) carbon is found in organic substances
such as:
carbohydrates, lipids, nucleic acids and
proteins.
Organisms are made of these substances
Organisms are also dependent on
carbon dioxide that is an inorganic
compound that contains carbon, too.
Carbon Cycle
• 2) Look at the picture on page 134 and
explain what the sources of carbon and
carbon dioxide are.
2) burning of fossil fuels releases
carbon dioxide
Organisms cellular respiration to break
sugars releases carbon dioxide in the
atmosphere
organisms decay after death releases
carbon in the soil and carbon dioxide into
the atmosphere