TOPIC 4.1 – SPECIES, COMMUNITIES& ECOSYSTEMS

4.1 – A – Organization

INTRO

IB BIO – 4.1 3Ecology is the study how organisms interact both with each other

and with their environments.

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Understandings

U1: Species are groups of organisms that can potentially interbreed to produce fertile offspring.

Key Terms

Species

Fertile

IB BIO – 4.1 4Members of a species are organisms that can interbreed to produce

fertile offspring. This means that their children can have children.

https://wordlesstech.com/wp-content/uploads/2011/08/Earth-is-home-to-8.7-million-species.jpg

* Sometimes, members of

different species can breed, but

their hybrid offspring are sterile.

Understandings

U2: Members of a species may be reproductively isolated in separate populations.

Key Terms

Population

IB BIO – 4.1 5Populations are formed by multiple

members of a species living and

interacting in the same area.

Members of a species can be split

into different populations. If far

enough apart, the populations will

not be able to reproduce.

http://www.futuretimeline.net/blog/images/320-lions-historic-range-map.jpg

Understandings

U7: A community is formed by populations of different species living together and interacting with each other.

Key Terms

Community

IB BIO – 4.1 6

https://loatree.com/wp-content/uploads/2015/05/amazing-coral-reefs-12.jpg

Communities are formed by populations of different species that live

in the same area and that interact with each other.

The community in

this photo includes:

• All species of fish

• Sea turtle

• Coral

• Any microscope

organisms in the

area

Understandings

U8: A community forms an ecosystem by its interactions with the abiotic environment.

Key Terms

Ecosystem

Abiotic Factors

IB BIO – 4.1 7

https://https://aos.iacpublishinglabs.com/question/aq/1400px-788px/components-ecosystem_fd9af634cd7d4843.jpg

Ecosystems form from the interactions between a community and its

abiotic factors in the environment. These are the non-living aspects

such as terrain, temperature, light, weather, water, nutrients, etc.

What are the abiotic components here?

REVIE

WIB BIO – 4.1

Identify examples of: species, population, community &

abiotic factors

4.1 – B – Nutrition & Sustainability

Understandings

U3: Species have either an autotrophic or heterotrophic method of nutrition (a few species have both methods).

Key Terms

Autotrophic

Heterotrophic

IB BIO – 4.1 10

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All organisms require a source of

organic nutrients, which are

needed for growth and

reproduction.

There are two types of methods

used to obtain these compounds:

• Heterotrophic - carbon

compounds are obtained from

other organisms (aka feeding

on others)

• Autotrophic – carbon

compounds are made from

CO2 and simple substances

(aka self feeding)

Understandings

U4: Consumers are heterotrophs that feed on living organisms by ingestion.

Key Terms

Consumers

IB BIO – 4.1 11

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Consumers are a type of

heterotroph that feed on other

organisms.

The organisms they ingest can

either be alive or dead for a

short period of time.

They internally digest materials

and absorb products in their

digestive tracts.

Understandings

U5: Detritivores are heterotrophs that obtain organic nutrients from detritus by internal digestion.

U6: Saprotrophs are heterotrophs that obtain organic nutrients from dead organisms by external digestion.

IB BIO – 4.1 12Detritivores are a type of

heterotroph that internally digest

detritus, which consists of

decomposing organic matter.

Saprotrophs are a type of

heterotroph that externally digest

detritus. They excrete digestive

enzymes and absorb the products.

https://upload.wikimedia.org/wikipedia/commons/8/8b/Woodlice_in_tree_bark.jpg

Understandings

U9: Autotrophs obtain inorganic nutrients from the abiotic environment.

Key Terms

Inorganic Nutrients

IB BIO – 4.1 13

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Autotrophs obtain necessary

elements in the form of inorganic

nutrients from the abiotic

environment (mostly soil/air).

These nutrients include:

• Carbon

• Hydrogen

• Oxygen

• Water

• Nitrates

• Phosphorous

Understandings

U10: The supply of inorganic nutrients is maintained by nutrient cycling.

Key Terms

Nutrient Cycling

IB BIO – 4.1 14

http://www.agriculturesnetwork.org/images/resources/images-learning/module-2-figure-5-soil-nutrient-cycle/image

The supply of inorganic nutrients on Earth is maintained by nutrient

cycling. Nutrients cannot be made by organisms. Instead, they are

passed on through consumption, waste matter and decomposition.

Understandings

U11: Ecosystems have the potential to be sustainable over long periods of time.

Key Terms

Sustainability

IB BIO – 4.1 15

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Sustainability refers to the ability of a system or process to continue

indefinitely. When resources are used faster than they can be

replaced, unsustainability results in resources being depleted.

For example, the human use

of fossil fuels in

unsustainable.

Since the resources are not

being replaced and use is

increasing, fuel sources will

eventually be depleted.

Understandings

U11: Ecosystems have the potential to be sustainable over long periods of time.

Key Terms

Sustainability

IB BIO – 4.1 16

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It is possible for natural

ecosystems to be sustainable

over long periods of time

For this to happen there are

three requirements:

• Nutrients must be available

through the nutrient cycle

• Waste products of species

should be detoxified and

used by others

• Energy must be available,

usually from the sun or

heat

Skills

S2: Setting up sealed mesocosms to try to establish sustainability. (Practical 5)

Key Terms

Mesocosm

IB BIO – 4.1 17

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Sealed mesoscosms are enclosed

areas that can be used in ecological

experiments.

Setups like the one shown here can

be used to study the effects of

factors on the system as a whole.

Factors that might affect

sustainability include:

• Light availability

• Types and populations of

producer species

• Types and populations of

consumer species

REVIE

WIB BIO – 4.1 181. Describe heterotrophic and autotrophic methods of

nutrition.

2. Compare nutrition methods of saprotrophs and

detritivores.

3. Describe how autrophs obtain inorganic nutrients.

4. Describe the nutrient cycle.

5. Define sustainability

6. Outline the requirements for sustainability to occur

in natural ecosystems.