Lecture 2 Flashcards
Survival mechanisms of life
Different shapes and forms of life reflect various unique survival mechanisms which developed as the result of evolution
Example of survival mechanism
Flight: bats, birds, insects
Organisms interact and take advantages of themselves for
Survival - no organism is living in isolation on earth
Survival mechanism for flowering plants
Use pollen for sexual reproduction
Pollen dispersal by wind: Interaction with the non living environment
Pollen dispersal by flying creatures: Interaction with other living species
Survival mechanisms of mammals
Nurture their youngling by feeding milk
Three groups:
Monotreme (Lays eggs)
Marsupial (kangaroos give early birth and nurture younglings in bags)
Placental
Evolution of marsupials
Diverged from other non sacked mammals early in mammalian evolution
Most basic requirements for survival
- Life needs energy
- Life uses carbon to build their body. Carbon are organic molecules: Compounds which as made of carbons and hydrogens connected by covalent bonds
Ultimate source of carbons are CO2 in atmosphere
What is used for energy
Adenosine triphosphate ATP (nucleotide)
Photosynthesis in the food chain
Most organisms cannot make organic molecules directly from co2 so primary producers convert co2 into sugars
Other organisms consume sugars produced by primary producers
How is co2 released back into environment
Released from organic molecules via respiration and decomposition
Photosynthesis and energy
Energy is lost at every step of this cycle
No such thing as 100% energy conservation
Carbon cycle can not be closed or else it will run out of energy
Needs to receive energy from outside the cycle (sunlight, geothermal energy)
Sunlight
Major source of energy
We categorize organisms by how they obtain energy and how they obtain carbon
Describe the energy flow diagram
Light comes in from the sun -> Plants convert sunlight into chemical energy -> Organisms use chemical energy to do work -> Heat is lost from the ecosystem
Chemical cycle
Plants take up chemicals from air and soil -> Chemicals in plants are passed to organisms that eat the plants -> Decomposers such as fungi and bacteria break down matter which returns chemicals back into soil
Phototroph
use light as energy source
Autotroph
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
etc: Plants, algae, cyanobacteria.
Some produce oxygen as a byproduct of photosynthesis
Chemotroph
Use chemicals (such as organic molecules) as energy source
Heterotroph
Use organic molecules as carbon source
Chemoheterotrophs
Consume organic carbon made by photoautotrophs
Vast majority of fungi and animals
etc. E coli
Describe a prokaryote
Cells without nucleus and other membrane bound organelles
Have flagella for motility
Describe Eukaryotes
Cells with nucleus and organelles. Involves the compartmentalization of cellular processes such as storage of genetic material, energy, production and photosynthesis
Describe some organelles of eukaryotes
Mitochondria for energy production
Ribosomes
Golgi apparatus
ER (protein + lipid production)
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) and (leaves, branches and roots)
Viruses
Have DNA or RNA genome packaged by proteins
Must infect host organism for reproduction
Ex: Smallpox virus
