LU 2 Complexity Of Life

Page 1

What does it mean to be alive ??

Auto conservation : main function for every living organism --> to make sure that it does not exist A.K.A conserve the species.

Auto reproduction : to reproduce, can reproduce.

Storage of info : All organism has genetic info stored in DNA, this DNA can be read & translated : genetic code which is universal.

Stability : Creatures remain stable & adapt towards what is happening around them/the environment. If they cannot adapt, they either die or move away if cannot stabilize.

Breathing - Fermentation : has metabolism to transform energy & matter from the env. to compounds & energy to be used.

Control : parts of an organism contribute --> survival of a group & conservation of their identity

Death

Origin of Life

Emergence of catalytic RNA : crucial early step

Catalysts are important and very needed in the chemistry of life

RNA : genetic messenger

The central Dogma of Modern biology : coded genetic info hard wired ---> DNA --> Transcribe to cassette containing messenger RNA (mRNA) : each mRNA cassette contains programs of protein synthesis of a particular protein // DNA --> RNA --> Protein --> common bio source of enzymatic catalysis

Structure of Biosphere

Species --> Can breed to produce fertile offspring, Resemblance in appearance, behavior, chem & genetic structure.

Population --> 1 group, same species, living at 1 place at the same time.

Community --> Population of diff species living together at 1 place.

Ecosystem --> a community of diff species that interact with each other & physical env. that supports it.

Biome --> region with a characteristic of plant community, ecologically same climatic conditions.

Page 2

Environment & Light

Organisms at the same habitat has their own separate niches such as strategies & living habits to avoid comp & extinction.

Light, water : community -- vertically stratified.

Photosynthesis, depends on certain depths to proceed, & other things like water clarity, sun angle & sea state. (Refer Lecturer)

Depth of light penetration : depend on amount & nature of dissolved & suspended constituent.

Oceanic : few particles : blue

Coastal : high amnt of phytoplankton : green

Estuarine : lots of suspended sediments : brown

Photosynthesis & Temp

dependant on amount of light & the color of light as not all photons are equivalent.

blue red : most efficient

Green : least efficient.

Temp in ocean varies depend on depth & latitude.

Chem rxn : slow at low temp & metabolism is defined by chemical rxn

Trophic

Enery transfer : 10% accept 90% lost to the env. as heat.

Primary producers : autotroph, making their own food & harvest sunlight.

Heterotrophs : consumers & eat organic matter.

Phytoplankton --> Zooplankton --> Small fish & larvae --> Mid size fishes --> tuna(top consumer)

Page 3

Biodiversity : No of species in a community

Diversity indices --> Simpson diversity : 1- [(species A) + (species B)+....]

Biodiversity over time =

General diversity increase

Change due to evolution & extinction(natural)

Recent changes : modern extinction caused by human populations such as over hunting/fishing & habitat destruction like deforestation & coral bleaching

Deforestation

Temperate forests : Thick rich topsoils, nutrients are stored in the soils. Has humus layer, thick one, of organic materials on top of subsoil.

Tropical rain forest : lateritic clay lack of nutrients, diminished. Has thin humus layers & nutrients stored in biomass. Loss of rainforest --> loss if nutrients * changes in water cycle.

Water Cycle

Destruction of rainforest --> Minimization of evapotranspiration which is where the source of H20 to the atmosphere. --> net temp increase

--> Soil moisture decreases, easy to run off (soil erosion etc)

Cause :

Social, political & economic drivers

Economic arguments - people & countries need hard currency (?)

Forest

Medical value : used as treatments

Agricultural value :-

Genetic diversity to ensure long term health

Variety limits vulnerability to diseases & pests

Modern agricultural --> limit diversity

Centers of genetic diversity for crops come from areas threatened by development, population pressures & deforestation

Seed banks (?)

Page 4

Ecosystem Stability

Complex relationship where in some settings, environment stability leads to high diversity but in some, intermediate disturbances lead to high diversity as well.

Loss of biodiversity effects ecosystem where enuf species are removed causes ecosystem to collapse.

System is maintained by a few keystone species whereby if those species were to die, the ecosystem would change drastically.

Elements of Life

23 basic element

if these elements are not available, growth and survival will be limited.

The Carbon Cycle

Basic Building block of life

Largest biogeochemical cycles

If it's not available, it rarely ever limits the marine productivity.

The Nitrogen Cycle

N : critical component for proteins, nucleic acids & pigment such as chlorophyll.

Traditionally, it is considered at the most limiting nutrient in the sea.

Leibig's

Law of the Minimum : Growth is limited not by the total of resources

available, but by the single source in shortest supply.