Lecture 2: Survival mechanisms of life Flashcards
Different shapes and forms of life reflect various, unique ___ which developed as the result of evolution
survival mechanisms
A common survival mechanism seen in some insects and majority of birds
flight
Organisms ___ of themselves for survival
interact and take advantages
Most flowering plants uses ___ for
sexual reproduction
pollen
How pollen is dispersed
- Pollen dispersal by wind
- Interaction with the non-living environment
- Pollen dispersal by flying creatures
- Interaction with other living species
How do Mammals nurture their young?
- nurture their youngling by feeding milk
Three groups of Mammals
- Monotreme (lays eggs)
- Marsupial
- Placental
What makes Marsupials unique?
Marsupials give early birth and nurture their younglings in their bags for an extended period. Marsupials diverged from the other ‘non-sacked’ mammals early in mammalian evolution
Most basic requirements for survival
- Life needs energy
- Life uses carbon to build their body
* Organic molecules: Compounds which are made of carbons and hydrogens, connected by covalent bonds
What is the ultimate source of carbon?
The ultimate source of these carbons are CO2 in our atmosphere
Photosynthesis and the food chain
- Most organisms cannot make organic molecules directly from CO2
- Primary producers convert CO2 into sugars
- Other organisms consume sugars produced by primary producers
- CO2 released from organic molecules via respiration and decomposition
What is lost at every step of cycle?
Energy is lost at every step of this cycle
* No such thing as 100% energy conservation
* Carbon cycle cannot be closed, or else it will run out of energy
How is energy required from outside the cycle?
- Sunlight
- Geothermal energy
____ sustains organisms on Earth
Sunlight is the major source of energy which is supporting organisms from outside Earth
Overall, we can categorize organisms by:
- How they obtain energy: Can they use sunlight directly?
- How they obtain carbon: Can they use CO2 directly?
Phototroph & Autotroph
– use light as energy source
– use CO2 as carbon source
Photoautotrophs
use light energy to make organic chemicals from CO2
* The ‘fixed’ carbon then gets used to build their body
Examples of Photoautotrophs
- Cyanobacteria, algae and plants
- Some photoautotrophs produce Oxygen (O2) as a byproduct of photosynthesis
Chemotroph & Heterotroph
– use chemicals (such as organic molecules) as energy source
– use organic molecules as carbon source
Chemoheterotrophs
consume organic carbon made by photoautotrophs
* Vast majority of fungi and animals, as well as heterotrophic microbes like E. coli
Major types of cellular organization
- Prokaryote – cells without nucleus and other membrane-bound organelles
- Eukaryote – cells with nucleus + organelles
- Compartmentalization of cellular processes such as storage of genetic material, energy production and photosynthesis
Eukaryote – “true kernel”
- The nucleus looked like a corn kernel under a microscope when scientists first discovered it
Major types of bodily organization
Unicellular organism
* Body of the organism consist of a single cell
* Most prokaryotes (bacteria and archaea)
* Some eukaryotes
* Still live as a population
Multicellular organism
* Body of the organism are composed of multiple cells
* Most non-microscopic eukaryotes
* Compartmentalization of bodily function into tissues
* muscles ,nerves, bones
* leaves, branches, roots
Viruses: acellular forms of ‘life’
- Viruses have DNA or RNA genome packaged by proteins
- Must infect host organism for reproduction
