2 - Biodiversity and Ecosystem Dynamics

What is biodiversity and why is it important?

What is biodiversity and why is it important?

• diversity at a range of levels (genetic, species, etc.) within an ecosystem

• biodiversity is important to bring stability to an ecosystem

What is genetic diversity and why its important?

• the variety of genes and forms of genes that occur within an ecosystem

• It is important for the survival of a species, as a wider gene pool gives a bigger chance of surviving a changing environment

What is species diversity

• the variety of species that live within a particular habitat or space

What is ecosystem diversity

• the number/abundance of species within an ecosystem

What are the definitions for species, population, community and ecosystem?

Species – a group of organisms with similar genetics that are able to reproduce with eachother

Population – a group of the same species living in the same area at one time

Community – the sum of all species living in an ecosystem at one time

Ecosystem – the sum of all abiotic and biotic factors and their interactions

What are the three main types of interactions within an ecosystem?

Competition

• Organisms competing for the same resource, occurs due to a limited number of resources

• Competitive exclusion principle – no two species can have the same niche in same haitat at one time

• Ex. Corals competing for space, nutrients and light

Predation

• When an organism captures and feeds on another organism

• Predator – hunter, prey – hunted

• Ex. Snake hunting a frog for food

Symbiosis

• When two species live closely together, there are three types (Mutualism, Commensalism, Parasitism)

What are the three types of symbiotic interactions between species?

Mutualism

• Both species benefit from a relationship

• Ex. Oxpeckers eat parasites of rhinoceros or zebras, birds get food, animals get pest control

Commensalism

• One member benefits, the other is neither benefited nor harmed

• Ex. Egrets live near cows grazing, can eat insects they dig up

Parasitism

• One member benefits, the other is harmed

• Ex. Tapeworms feed on human insides, to get nutrients

What are autotrophs?

• Producers

• Manufacture organic compounds from simple inorganic compounds, photosynthesis

• Use organic compounds for themselves as energy and for all other members within that ecosystem

What are heterotrophs? (+ 4 sub divisions)

• consumers

• Obtain energy by eating other organisms or parts of them

• Have sub-divisions

  -herbivore – eats plants

  -carnivore – eats animals

  -omnivore – eats both plants and animals

  -detritivore – eat decomposing organic matter

What are abiotic and biotic factors?

Abiotic Factors

• Non-living factors

• Atmosphere: wind, light, temperature. Water: nutrient levels, pH levels. Soil: nutrient availability

Biotic Factors

• Living factors

• Producers, consumers, detritivores, decomposers and their interactions

How are species named? (scientific name)

Genus species

What are the 7 taxonomic levels?

Domain Kingdom Phylum Class Order Family Genus Species

What is a domain, kingdom and species?

Domain

• Three domains of life; archaea (prokaryotes), bacteria (prokaryotes), eukarua (eukaryotes)

Kingdom

• Encompasses all related species; anamalia, plantae, protista, fungi, archaea, bacteria

Species

• A group of similar organisms that can interbreed and produce fertile offspring

What are the three factors when classifying species?

Physical features

• logically, organisms with similar features are often closely related

Reproductive species

• giving birth to live young, laying eggs, methods of caring for young, etc.

Molecular sequencing

• examining DNA sequences and protein sequences of organism allows for inferences to be drawn regarding common ancestors and therefor the degree of relatedness

If two scientific name have same genus are they similar?

yes they are closely related

If two scientific name have different genus but same species name are they similar?

no, they are different species and not closely related

What is an adaptation? + names of three types

• An adaptation is a feature that seems to equip an organism for survival in its environment

• Helps an organism to: find food/water, find protection/avoid predators, reproduction

• They are hereditary -> pass on to next gen if it helps them survive

• Structural, Behavioural, Physiological

What are the three types of adaptations?

Structural

• An adaptation to the structural form of an organism; a physical feature

• Eg. Body coverings, teeth, movement, camouflage

Behavioural

• Activities that help an organism to survive

• Can be instinctive (nature) or learned (nurture)

• Eg. Social behaviour, behaviour for protection, migration, nocturnal,

Physiological

• An adaptation to the internal or biochemical functioning of an organism

• Eg. Control of body temp., organs, breeding times, venom

What is the purpose of an adaptation?

allow organisms to survive in their environments

What is an ecological niche?

• The way in which a population of organisms function within an ecosystem

• A niche may refer to the populations habitat in an ecosystem, or the role that an organism plays in an ecosystem

• Example: photosynthesis in plants, beavers making dams,

• The role a population of organisms completes in an ecosystem

What is a niche overlap?

• When populations of two species have a similar niche, they will compete where parts of the niche overlap

• Ex. Type of food eaten, light, habitat

What is the difference between a fundamental and realised niche?

Fundamental

• The entire set of conditions under which a species can survive and reproduce

Realised

• The set of conditions used by a species, after interactions with other species are taken into account

What is ecosystem stability?

• A stable ecosystem is one which is maintained over a long period of time through a rich diversity of species

• An unstable ecosystem has low diversity which will lead to a less resilient ecosystem which cant adapt to change

What is a keystone species?

• The species within an ecosystem whose ecological niche (role) affects the stability of the ecosystem greatly

• The extinction of a keystone species is a serious prospect to face, as it can weaken the overall stability of an ecosystem

How is energy used in an ecosystem?

• The sun is the primary source of energy for most (not all) ecosystems

• Energy is vital for organisms to survive

• Light energy (radiant) -> chemical energy

How is energy transferred in an ecosystem

• Stored chemical energy is passed through the trophic levels

• First order (or primary) consumers feed on producers, second order (or secondary) consumers feed on first order consumers and so on

What are the three types of ecological pyramids

Pyramid of numbers = number of organisms per unit over area

Pyramid of biomass = total weight of dry organic matter of organisms at each trophic level given in an area

Pyramid of energy = shows the amount of energy input to each trophic level in a given area

How much energy is passed on to the next trophic level and why?

• 10% passed on, 90% lost

• The majority of energy is lost as heat energy during respiration, muscle movement and body waste

How do biogeochemical systems work?

• decomposers break down the organic material like carbohydrates, proteins, nucleic acids, and lipids, into inorganic substances

• These are then taken up by producers and incorporated back into new plant material and in turn to the bodies of consumers

• As matter is neither created nor destroyed in the ecosystem, it is important to cycle matter

How does the carbon system work?

- plants use photosynthesis to incorporate carbon dioxide from the atmosphere into tissue

- consumers feed on plants to incorporate carbon into their own tissues

- decomposers break down dead organisms, releasing carbon dioxide back into the atmosphere

How does nitrogen system support plant growth

• nitrogen is essential for plant growth

• Nitrogen fixing bacteria convert atmospheric nitrogen into nitrates which is a readily available form of nitrogen to be used by plants for growth

What are the three types of change in an ecosystem

Daily Change

• The abiotic components of an ecosystem change during the day as day passes into night, for example; Light Intensity, Air temperature and humidity

Seasonal Change

• The abiotic factors of many terrestrial ecosystems in spring support the reproduction of most plant and animal species, and the growth and development of offspring they produce

• The size of populations of many species may change so much that the community begins to visibly change

Long Term Change

• Long term change to ecosystem occurs if the abiotic and biotic components of the ecystems are significantly altered

  - colonisation of new species to the area

  - natural disaster

  - human activity eg. Deforestation

• Events like this may change the abiotic and biotic factors so much that they instead of supporting earlier collections of species in the ecosystem, they favour different living things

• This more unidirectional type of ecosystem change is called ecological succession

What is ecological succession (primary + secondary)?

Ecological Succession

• May start in a virtually lifeless area that lacks soil; for example beginning on bare rock uncovered by a gradual decrease in sea level, lake level, or the retreat of a glacier

• It also occurs after the formation of volcanic islands. This type of sucession is called primary succession

Ecological Succession – Secondary

• Ecological succession may also occur in an already mature ecosystem if it experiences a natural disaster or is subjected to a major human activity for example a woodland burnt by a bushfire or cleared for agriculture

How does climate change impact ecosystems

• burning fossil fuels, deforestation

• long-term shift in weather patterns as fossil fuels trap heat in atmosphere

• changes conditions in ecosystems, saltwater intrusion

• can affect and destroy ecosystems

What are 5 ways humans impact ecosystems

• habitat fragmentation

• climate change

• introduced species

• agriculture