Download Topic 2: Ecosystems and ecology

Topic 2: Ecosystems and
ecology
Starter:
Read the
2.1 Species and population
definitions your
partner wrote
yesterday. Do
you
agree/disagree
with them.
Discuss.
https://www.youtube.com/watch?v=GlnFylwdYH4
2.1 Learning objectives
• Define the following terms:
•
•
•
•
•
Species
Habitat
Ecosystem
Niche
Biotic and Abiotic Factors
There are LOADS of
definitions to learn
today (Sorry). If you
don’t understand them
at the end of the lesson
make sure you spend
some time getting
yourself familiar with
them.
• Describe the concepts of fundamental and realised
niche.
• Explain what is meant by carrying capacity and how
limiting factors affect population growth.
In your books:
What is a species?
• A group of organisms that share common
characteristics and that interbreed to
produce fertile offspring.
• Why can’t we use just appearance alone?
• Why can’t we just use genetic analysis
alone?
1. Write the
definition of
species.
2. Using
examples
explain why
defining a
species can
be difficult.
Which animal?
• Pysgodyn aur (Welsh)
• Carassius (Malthese)
• Peix de colors (Catalan)
• Goudvis (Afrikaans)
• Guldfisk (Swedish)
Latin Binomials
Carassisus auratus
Genus species
Can be shortened to: C.
auratus
When typed: italics
When handwritten: underlined
We must now be referring to species
by their proper names.
E.g.
1. Instead of fish we must say
Goldfish or Carassisus auratus
2. Instead of fish we must say
Atlantic Salmon or Salmo salar
In your books:
Explain why it is important for us to use Latin
binomials.
In your books:
And what is a habitat?
• The environment in
which a species
normally lives.
• Different individuals
within the same species
can live in very different
habitats.
• Habitats can change
over time as a result of
migration.
1.
2.
Write the definition of habitat.
Explain how to habitat of the
Pacific golden plover changes
through out the year.
Aand…. What is an ecosystem?
• A biological community of interacting organisms
and their physical environment.
In your books:
1.
Write the definition
of an ecosystem.
Biotic and Abiotic factors within
an ecosystem
Biotic Factors: The living
components of an
ecosystem.
NOT just a list of all the
living things in an
ecosystem, but the roles
played by each of those
organisms.
Abiotic Factors: The
physical and chemical
components of an
ecosystem.
In your books:
1.
2.
Write a definition of both biotic and abiotic factors.
Using the diagram to help you list the biotic and abiotic
factors within specific ecosystem.
Which factors are biotic and
which are abiotic?
Soil readings from 3 different sites in a temperate woodland
pH
Moisture Content
Site 1
Dissolved Nitrates
Site 2
Site 3
Note: Correlation NOT causation
Microbe Diversity
Aaand… What is an ecological niche?
• A role taken by a type of
organism within its community.
• The sum of a species' use of the
biotic and abiotic recourses in
an environment.
Includes:
• Space utilisation
• Food consumption
• Temperature range
• Moisture
requirements
In your books:
1.
Write the definition
of an ecological
niche.
The difference
between a
niche and
habitat:
Niche is like a
occupation
(what an
organism does),
whilst a habitat
is like an
address (where
an organism
lives)
Turn to the back of your books
• Match the key word with its definition (just letter
and number)
1) Habitat
2) Abiotic Factor
3) Ecosystem
4) Niche
A) The living components of an ecosystem.
• 1Dof organisms that share common
B) A group
characteristics and that interbreed to produce fertile
• 2E
offspring.
C) The• sum
3Fof a species' use of the biotic and abiotic
recourses in an environment.
4C
D) The• environment
in which a species normally
lives.
• 5A
5) Biotic Factor
E) The physical and chemical components of an
ecosystem.
• 6B
6) Species
F) A biological community of interacting organisms
and their physical environment.
Niches and
competition
• If two species have an identical or
very similar niches they cannot live
in the same habitat.
• The Eurasian red squirrel and Eastern
grey squirrel both eat very similar
foods.
• The grey squirrel outcompetes the
red squirrel.
Data interpretation: Competition
The biologists Lotka and Volterra theorized that no two species with similar
requirements for resources (food, shelter, etc.) could coexist in the same niche
without competition driving one to local extinction.
In 1930s G.F. Gause tested the Lotka-Volterra theory by growing two Paramecium
species in identical conditions. However, he found that if he grew them together
that only one species prevailed.
In your books:
Using what you
know explain the
findings of G.F.
Gause.
You must describe
the trends you see
in the graphs in
your explanation.
Fundamental vs. Realised Niche
• A species may not be able to occupy its entire niche
because of the presence of other species.
Fundamental niche: the set of resources a population is
theoretically capable of using under ideal conditions.
Realised niche: the resources a population actually uses.
Case study: Joseph Connell’s barnacles
• Read through the
information sheet.
• Then answer the
following questions:
1. What is the habitat of the two
species?
2. Why did Connell need to do both
experiments to make an accurate
conclusion? What information
would be missing without the
second experiment?
3. Use this example to explain the
differences between fundamental
niche and realised niche
Chthamalus
Balanus
Carrying capacity
• The number of organisms a region can support
without environmental degradation. (Population
density or food).
In your books:
Describe what is happening in the
graph.
Use this description to help write an
explanation of carrying capacity.
Interspecific relationships
Inter = different
Time
Number of
African lions
Number of
Thomson’s Gazelle
• Predator prey
relationships.
0
15
50
6
5
200
• Parasitic
relationships.
12
10
300
18
15
50
• Mutualistic
relationships.
24
5
200
30
10
300
36
15
50
Examples:
Each species
can influence
the population
dynamic of
other species.
In your books:
1. Using the data above draw a
graph of the population of the two
species over time.
2. Explain the pattern in the graph.
In your books:
Explain how humans have affected the carrying capacity of
certain ecosystems? Try to think of how we have increased the
carrying capacity of some ecosystems, not just decreased.
Limiting factors
Food
Space
Predation
Disease/Parasites
J-Curve:
exponential
growth, no limiting
factors
S-Curve: logistic
growth, limiting
factors slow the
rate of growth
In your books:
Draw the graph and then explain what it shows.