L5 Ecosystems and Living Organisms

7/28/2019 L5 Ecosystems and Living Organisms

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Lecture 4

Ecosystems &Living

Organisms

Lecture 5

Ecosystems & Living

Organisms


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Interactions Among Organisms

http://healthyhomegardening.com

http://proberts10.wikis.birmingham.k12.mi.us


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Ecosystems & Living Organisms

There are 3 main interactions among organisms:

1. Predation

2. Symbiosis

3. Competition


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Predation

- relationship whereone organism

consumes another

- includes animals

eating other

animals, animalseating plants and

plants eating

animals.

Venus Flytrap

http://www.bio.miami.edu/dana/dox/symbiosis.html


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Predator

- depends totally or in

part on killing another

organism for its food

Prey

- organism killed and

eaten by a predator


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Predator Strategies

Predator strategies include:

1. Pursuit (chase)

2. Ambush (lie in wait)

3. Special hunting traits e.g.,

speed, agility, claws

4. Traps

5. Hunting in packs


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Prey Strategies

Plant Defense Strategies include:

- spines orthorns

- leathery orwaxy leaves

- produce bitter orpoisonous

chemicals


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Prey Strategies

Animal Defense Strategies include:

- fleeing

- camouflage

- mechanical defenses, e.g.,

horns, quills

- group living

- warning coloration


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Symbiosis

- a close relationship between 2 or moreunrelated species usually involving nutrition

The 3 main types of symbiotic relationships:

1. Mutualism

2. Commensalism

3. Parasitism


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Mutualism- symbiotic

relationshipwhere both

organisms

benefit from

each other

shark

remora

- symbiotic relationship where both organisms

benefit from each other

Mutualism

Clownfish and Sea anemonehttp://www.mahalo.com


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Commensalism

- symbiotic

relationship where

one organism

benefits while theother is

unaffected

Epiphyte in the lowland

dipterocarp rainforest, Danum Valleyhttp://www.eoearth.org


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Commensalism - Barnacles encrusted on

the surface of a whale


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Head of a tapeworm

Hooks and suckers on

head for attachment to

body organs

Tapeworm

http://www.bio.miami.edu


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Tomato Hornworm covered with cocoon of braconid waspshttp://www.cals.ncsu.edu


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Ecological Niche

Niche

- the sum total of all the requirements and

activities of a species

- an organisms unique role

- an organisms profession

- reduces competition between species


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Fundamental vs. Realized Niche

Fundamental Niche

- full potential range of physical, chemical &

biological factors a species could use if therewere no competition from other species


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Fundamental vs. Realized Niche

Realized Niche

- the portion of the fundamental niche that a

species actually occupies

- species with a narrow realized niche (specialist

species) are more susceptible to extinction


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Habitat

- the physical & biological resourcesrequired by

an organism

- an organisms address


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Competition

-if2 different speciesrequire a common

resource they are said to

be in competition for it

http://www.biotopics.co.uk


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Competitive Exclusion Principle

- also called Gauses Principle

- two (2) speciescannot live in the same identical

niche & if they try one (1) will be excluded


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Evolution & Succession


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Evolution & Succession

Evolution

- change in the genetic material of a population of

organisms from one generation to the next

- involve processes which introduce new variations

/ characteristics (mutations or interbreeding) and

processes that make new variants either

increasingly rare or common

- does not necessarily mean speciation


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Natural Selection- a theory advanced by

Charles Darwin (18091882) to explain how

evolutionary change

occurs

- ifcertain individuals are

better able to survive &

leave more offspringbecause of their genetic

traits, then frequency of

the genes will change over

subsequent generations


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Succession

Successionis a process of community development

that involves a changing sequence of species.

S i


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Succession

The pioneer communi tyis the first community to colonise

or re-colonise an area.

Primary successionis community development in an area

that has not been previously inhabited e.g. on bare rock,sand, hardened lava flow from volcano, area left by a

retreating glacier.

Secondary successionis community development in an

environment that has been previously inhabited but was

destroyed by some process e.g. fire, flood, harvesting etc.

Usually takes thousands of years to reach climax community
http://upload.wikimedia.org/wikipedia/commons/8/8b/Rangitotolavapath.jpghttp://upload.wikimedia.org/wikipedia/commons/8/8b/Rangitotolavapath.jpg


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Primary Succession on a lava field on the

Rangitoto Island near New Zealandhttp://en.wikipedia.org

Usually takes thousands of years to reach climax community

Usually takes hundreds of years to reach climax community
http://upload.wikimedia.org/wikipedia/commons/8/8b/Rangitotolavapath.jpghttp://upload.wikimedia.org/wikipedia/commons/8/8b/Rangitotolavapath.jpghttp://upload.wikimedia.org/wikipedia/commons/8/8b/Rangitotolavapath.jpghttp://upload.wikimedia.org/wikipedia/commons/8/8b/Rangitotolavapath.jpghttp://upload.wikimedia.org/wikipedia/commons/8/8b/Rangitotolavapath.jpghttp://upload.wikimedia.org/wikipedia/commons/a/a2/Secondary_succesion_cm01.jpghttp://upload.wikimedia.org/wikipedia/commons/a/a2/Secondary_succesion_cm01.jpg


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Secondary Succession

Secondary Succession on an uncultiv

htt // iki

Usually takes hundreds of years to reach climax community
http://upload.wikimedia.org/wikipedia/commons/a/a2/Secondary_succesion_cm01.jpghttp://upload.wikimedia.org/wikipedia/commons/a/a2/Secondary_succesion_cm01.jpghttp://upload.wikimedia.org/wikipedia/commons/a/a2/Secondary_succesion_cm01.jpghttp://upload.wikimedia.org/wikipedia/commons/a/a2/Secondary_succesion_cm01.jpghttp://upload.wikimedia.org/wikipedia/commons/a/a2/Secondary_succesion_cm01.jpg

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L5 Ecosystems and Living Organisms