Ch. 1: Principles of Life Flashcards
What are the nine characteristics that all living organisms share and what is the implication?
1) are composed of a common set of chemical parts, such as nucleic acids
2) are composed at a microscopic level of similar structures, such as cells enclosed within membranes
3) depend on intricate interactions among structurally complex parts to maintain the living state
4) convert molecules obtained from their environment into new biological molecules
5) extract energy from the environment and use it to carry out life functions
6) replicate genetic information in the same manner when reproducing themselves
7) have a fundamental set of genes that share structural similarities
9) evolve through gradual changes in their genetic information
The characteristics shared by all organisms logically lead to the conclusion that all life has common ancestry
How long ago was the Earth formed?
~4.5 billion years ago
Explain what occurred ~3.8 billion years ago.
Prokaryotes were formed, the 1st appearance of life
A unicellular liquid membrane formed around organic molecules that could capture and replicate energy.
Explain what occurred ~2.5 billion years ago.
Before this time, prokaryotes were largely confined to oceans and then some prokaryotes developed the ability to photosynthesize. Photosynthesis is the process in which energy of sunlight is captured and oxygen is generated as a by-product. Oxygen then increased in concentration in the atmosphere, making aerobic metabolism possible. This made it possible for organisms to leave the protection of the water and live on land.
Explain what occurred 1.5 billion years ago.
Prokaryotic cells grew and were able to attach and engulf smaller cells. The smaller cells survived inside and had different functions and pH levels. These were the first eukaryotic cells.
What are the two developments that made the evolution of multicellular organisms possible ~1 billion years ago?
1) the ability of a cell to change its structure and function to meet the challenges of a changing environment
2) the ability of cells to stick together after they have divided and to act in a coordinated manner
Once organisms became multicellular, it became possible for certain cells to specialize.
Explain an effect of oxygen concentration building up in the atmosphere that occurred 800 million years ago.
Ozone (O3) accumulation in the upper atmosphere. Ozone has the property of preventing excess ultraviolet light from the sun from reaching Earth. This ozone accumulation shielded the landmass from radiation enough to allow the movement of organisms to land.
Explain what occurred approximately 450 million years ago.
the first land plants
What occurred ~365 million years ago?
first land animals
What occurred ~230 million years ago?
first dinosaurs
What occurred ~200 million years ago?
first mammals
What is a population?
groups of individuals of any one species that live together
Why is organization of life necessary?
it’s essential for cells to function in a multicellular organism, which has many levels of organization
What is a community?
populations of multiple species interacting
What is a landscape?
multiple communities interact within a landscape
