Topic 4: Ecology 4.1 SPECIES, COMMUNITIES AND ECOSYSTEMS

Understandings (Aims)• Species are groups of organisms that can potentially interbreed to produce fertile offspring

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

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

•Consumers are heterotrophs that feed on living organisms by ingestion.

Understandings (Aims)•Detritivores are heterotrophs that obtain organic nutrients from detritus by internal digestion.

•Saprotrophs are heterotrophs that obtain organic nutrients from dead organic matter by external digestion.

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

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

Understandings (Aims)•Autotrophs and heterotrophs obtain inorganic nutrients from the abiotic environment.

•The supply of inorganic nutrients is maintained by nutrient cycling.

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

Ecology• A branch of biology that studies ecosystems.

• Ecology defined is the study of relationships between living organisms and between organisms and their environment.

• Several terms (vocabulary) are associated with ecology:• Environment

• Habitat

• Biotic versus Abiotic

• Population

• Community

• Ecosystem

• Biosphere

Important Vocabulary Associated with Ecology:1. Habitat – the environment in which a species normally

lives in (the location of a living organism)

2. Biotic – living organisms part of an environment

3. Abiotic – nonliving portions that are part of an environment (rocks, water, temperature, and air)

Important Vocabulary Ctd:4. Species – are groups of organisms that can potentially interbreed to produce fertile

offspringa. Most species have some method of trying to ensure that they reproduce with

other members of their species. (ex: elaborate and distinctive courtship dances from birds of paradise)

i. Often display an exotic plumageii. Ability to recognize the same type of species

b. Species are in search for a “fit” and sustainable partnerc. Interbreeding – when two members of the same species mate and produce

offspringd. Crossbreeding – when members of different species breed together (often results

in infertile offspring)

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Important Vocabulary Ctd:5. Populations – is a group of organisms of the same species who

live in the same area at the same time.a. If two populations live in different areas – no interbreeding

will occur

b. If no interbreeding every occurs, then they may become reproductively isolated

i. Reproductively isolated – gradual difference in their physical characteristics (phenotype)

Important Vocabulary Ctd:6. Nutritional Methods – all organize need a constant supply of food for life

to go on.a. Autotroph – make their own carbon compounds (from CO2 and other

simple substances)i. May also be called a producer or “self-feeder”ii. Producers – 2 typesiii. Photoautotrophs – feed via photosynthesis (green algae and plants)iv. Chemoautotrophs – feed via chemosynthesis (deep sea vent dwellers)

b. Heterotroph – obtain their carbon compounds from other organisms (feed on others for nutritional needs)

i. Divided into groups based on they organic molecules they use and the method of taking them in

Important Vocabulary Ctd:7. Consumers – heterotrophs that feed on living organisms by ingestion.

a. Feed off other organisms (can be alive or dead)

b. Examples: mosquitoes and lions

c. Ingest their food – take in undigested material from other organisms

d. Digest it and absorb the products of digestion

e. Can be divided into trophic levels based upon what other organism they consume

i. Primary consumers, secondary consumers, tertiary consumers

ii. No one consumer fits neatly into any of the following trophic levels because of dietary needs

iii. Trophic level – position it occupies in a food chain

Important Vocabulary Ctd:8. Detritivores – are heterotrophs that obtain organic nutrients from

detritus by internal digestion.a. Organisms discard large amounts of matter: dead leaves, hair,

and feces

b. Detritus – rarely accumulates

c. Detritus – source of nutrition for detritivores and saprotrophs

d. Ingest dead organic matter and then digest it internally and absorb the products of digestion

e. Examples: earthworms and larvae of dung beetles

Important Vocabulary Ctd:9. Saprotrophs – heterotrophs that obtain organic nutrients from

dead organic matter by external digestion.a. Secrete digestive enzymes into the dead organic matter and

digest it externally

b. Absorb the products of digestion

c. Examples bacteria and fungi

d. Also known as a decomposer – help break down carbon compounds in dead organic matter and release elements such as nitrogen into the ecosystem

Important Vocabulary Ctd:•Some organisms do exist that are BOTH an autotroph and heterotroph.

•Example of both feeding patterns:• Euglena gracilis

•Has chloroplasts – carries out photosynthesis only when there is enough light

•Also feeds on detritus via endocytosis

•Mixotrophic feeders

Important Vocabulary Ctd:10.Communities – a group of populations living together in an area

and interacting with each othera. All species are dependent on relationships with other species

for long-term survival

Important Vocabulary Ctd:11. Ecosystems – formed by a community and the abiotic environment

a. Organisms depend on non-living surroundings of air, water, soil, or rock (abiotic factors)

b. Abiotic factors exert powerful influence over organisms

i. Examples: rocky shore waves creates a specialized habitat for certain organisms (barnacles)

ii. Examples: sand dunes – develop along the coast because of sand being blown in via wind; specialized plants grow there to stabilize the sand and their leaves break the wind

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Inorganic Nutrients• Autotrophs and heterotrophs obtain inorganic nutrients from the abiotic environments.

• Living organisms need a supply of chemical elements:

• C, H, and O are needed for carbohydrates, lipids

• N and P are needed also to help make carbohydrates, lipids, and amino acids

• Autotrophs obtain all of the elements that they need as inorganic nutrients from the abiotic environment.

• Heterotrophs obtain these two elements and others as part of the food they consume.

Nutrient Cycles• Supply of inorganic nutrients is maintained by nutrient cycling• Carbon Cycle • Nitrogen Cycle• Phosphorus Cycle• Water Cycle

• Chemical elements can be recycled

• Organisms absorb the elements that they require, use them, and then return them to the environment. Atoms are unchanged.

Carbon Cycle

Nitrogen Cycle

Phosphorus Cycle

Nutrient CyclesNutrient Cycle Videos - Crash Course

Sustainability of ecosystems• Ecosystems have the potential to be sustainable over long periods of time.

• Some current human uses of resources are unsustainable.

• Sustainability – is defined as a process that can continue indefinitely

• Example of unsustainable activity: fossil fuel use

• Requirements for sustainability in ecosystems:• Nutrient availability• Detoxification of waste products• Energy availability

Sustainability Video

Sustainability •Nutrients can be recycle indefinitely – done correctly no lack of chemical elements

• Energy cannot be recycled - sustainability depends on a supply of constant energy from the light of the sun

• Example: Mount Tambora Eruption (1815) consequences

• Dust in the atmosphere reduced intensity of sunlight for several months

• Resulted in crop failures globally and deaths due to starvation