Lecture 1: Principles of Life Flashcards
What is life?
all organisms are a mixture of water, minerals, proteins, sugars, and fats, and yet living organisms are fundamentally different from mere chemicals.
life in diverse forms: the diversity of known life- all the species that have been identified and named-includes:
290,000+ species of plants, 52,000 species of vertebrates (animals with backbones) and more than 1 million species of invertebrates. Biologists add thousands of newly identified species to the list each year. Estimates of the total number of species range from 10 million to more than 100 million.
Life on Earth: Our 1 example:
origin of life and its evolution is closely linked with the physical properties of the universe in general. local planetary conditions
BIG BANG
13.8 billion years ago there was an expansion, and from that expansion all matter came to be
CHEMISTRY:
all the elements are from the stars, we can’t do much with just hydrogen and helium, carbon, oxygen, nitrogen, phosphorus, sodium, etc
Life seems to be more:
like a process than a thing
Temporal perspective:
13.8 billion years, it took a long time to happen-2.8 billion years ago.
Journalist approach to life:
who: cannot be answered by science at its current state of development. What: natural consequence to the evolution of matter. When: as soon as it was possible. Where: earth. Why: science can’t answer this yet.
6 MAJOR COMPONENTS OF LIFE
- actively maintain organized complexity. 2. acquire and use materials and energy. 3.sense and respond to stimuli. 4.growth and development, 5. reproduce. 6. evolve
Organization and complexity:
no ghosts, no energy clouds, “beings” have defined edges. complex internal organization. All living things are made of cells: multicellular or unicellular, plasma membranes, compartmentalization
compartmentalization
all cells have a defined volume enclosing the chemicals necessary for survival, while keeping toxic chemicals outside. this is achieved by membranes. larger organisms are further subdivided (cells, tissues, organs) in order to separate specific functions within the same organism.
Relationship between structure and function:
within biological systems, structure (the shape of something) and function(what it does) are often related, with each providing insight into the other. The correlation of structure and function can be seen at every level of biological organization. Consider your lungs, which function to exchange gases with the environment, Oxygen in and carbon dioxide out
Structure of lungs correlates with their function
increasingly smaller branches end in millions of tiny sacs in which the gases cross from the air to your blood and vice versa. this structure provides a tremendous surface area over which a very high volume of air may pass.
cells display a correlation of structure and function:
as oxygen enters the blood in the lungs, it diffuses into red blood cells. The shape of red blood cells provides a large surface area over which oxygen can diffuse
2: Acquire materials and derive energy from them:
break down nutrients, all cellular processes require energy, metabolism:sum of all chemical activity taking place in an organism
Regulation= internal constancy
autopoiesis: organisms do a lot of things just to stay the same (structurally speaking, maintenance) chemical reactions require very specific conditions, temperature, ph, etc.
Homeostasis: organisms must maintain constant internal environment, NOT equilibrium, non-stop chemical replacement is essential to life
Energy Transformations: Pathways that transform energy and matter:
Various cellular activities of life are work, such as movement, growth, and reproduction, and work requires energy. Life is made possible by the input of energy, primarily from the sun, the transformation of energy from one form to another.
- Respond to Stimuli:
all organisms perceive, individuals must exhibit behavior in response to external stimuli, all organisms can display behavioral responses
We do not usually thing about plants in terms of behavior:
behavior is the way that all organisms or living things react to stimuli. stimuli include chemicals, heat, light, touch, gravity, and others. For example, plants respond with growth behavior when light strikes their leaves. Behavior can be categorized as either instinctive (present in the living thing from birth) or learned (resulting from experience)
- Growth and development:
at some time in its life, every organism grows. bacteria grow wby enlarging their cells, then dividing to reproduce. Animals and plants grow by increasing the numbers of cells in their body via cell division. Growth may be accompanied by development, in which a growing organism becomes more complex.
- Reproduce
organisms reproduce by dividing in half, producing seeds, or bearing live young. Directions for the growth and development of organisms are contained in the genetic material: Deoxyribonucleic acid
DNA: Genetic program:
all cells use DNA as the chemical material of genes, the units of inheritance that transmit information from parent to offspring. The language of life has an alphabet of just four letters: A, T, C, and G. Adenine, Thymine, Cytosine, and Guanine. a lot of genes are similar across organisms.
Information flow:
For life’s functions to proceed in an orderly manner, information must be stored, transmitted, used (development is “genes in action”). Every cell in your body was created when a previous cell transmitted information (DNA) to it. Even your very first cell, the zygote, or fertilized egg, contains information passed on from the previous generations.
- Evolution
similarities are found among different types of organisms as a result of common ancestry. What can account for this combination of unity and diversity in life? the scientific explanation is the biological process called evolution.
Evolution
life changes over time (it evolves). each species is one twig of a branching tree of life extending back in time through ancestral species more and more remote. Species that are very similar, such as the brown bear and the polar bear, share a more recent common ancestor that represents a relatively recent branch point in the tree of life.
problems with our description of life:
are seeds alive? with correct environmental stimulus they will germinate, without that they are inert. Viruses almost fit but they can’t do all the processes on their own. Prions are self replicating proteins. tardigrades are simple organisms that can be dehydrated into a powder, and which can be stored in this state for years, but if water is added, the tardigrades resume their living functions.
Prokaryotic life took:
1 billion years after earth formed. eukaryotic cells took another 2 billion years, multicellular life took another 1 billion years.
