Bio 114 Notes

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Evolution by natural selection is slow but can be observed in certain situations.

How to spot evolution in real time:

Artificial selection – manipulation by humans such as breeding dogs or growing corn.

Repro-rate – rate of reproduction.

Stochastic Event: unexpected disaster like a volcano eruption or tornado.

(Research geological time)


Biology – Study of living things.

Living things – all the organisms descended from a single-celled ancestor.

* Characteristics:
Contains genetic information used to reproduce
Genetically related and have evolved
Can convert molecules from their environment into new biological molecules Can extract energy from the environment and use it to do biological work Can regulate their internal environment (what is internal environment)

Evolution: who lives and who dies with/without reproducing. Diffusion was a big part at the origin of evolution. Organisms evolve through differential survival and reproduction.

All life started as unicellular organisms (single cell carries out all functions of life)

Multicellular organisms: made of many cells specialized for different functions.

Cells are studied using microscopes.

Van Leeuwenhoek and Hooke were the first to observe living organisms and their cells under microscopes in the late 1600’s.

Charles Darwin proposed that all living things are descended from common ancestors.

Evolution by natural Selection

Survival of the fittest – Herbert Spencer

i.e. Survival of the reproducing

Fittest = The individual whose genes are most highly represented in the next generation ≠ most aggressive.

Killing off a species is bad for eliminating gene pools, but not always good.

Some survival of the fittest refer to a species such as bees (which are eusocial) They are 75% related to each other due to having one queen.

Cell Theory:

Cells are the basic structural and physiological units of all living organisms. Cells are both distinct entitites and building blocks for more complex organisms (Schleiden and Schwann 1838)

Beliefs about spontaneous generation prevailed when the original theore was set forth. (put meat in a jar and maggots will appear out of nowhere instead of somehow entering)

Modern Cell Theory:

All cells come from preexisting cells
All cells are similar in chemical composition
Most of the chemical reactions of life occur within cells

Multicellular organisms have an internal environment that isn’t cellular.

Cells specialized into tissues, tissues form organs, and organs form organ systems.

Living organisms interact, these can be positive or negative and can be intraspecific or interspecific.

Individuals are part of populations
Interacting populations of many different species make up a community and interacting communities in a given area form ecosystems.

Life first appeared about 3.8 billion years ago.
For 2 billion years, life consisted of only single celled prokaryotes. These cells were in the oceans, protected from UV radiation. At this time, there was no oxygen (O2) in the atmosphere, hence no protective ozone (O3) layer. Some greenhouse gasses regulating temperature of the planet.

Search biotic, cyanobacteria and abiotic.

Photosynthesis evolved about 2.5 billion years ago. Consequently, O2 accumulated in atmosphere, aerobic metabolism began and the ozone layer formed, allowing life on land. Lot’s of organisms died off when O2 hit because they were being oxidized.

Cyanobacteria in the ocean produced oxygen and formed the ozone layer.

Aerobic respiration – main respiration for humans. Produces 39 ATP. Anaerobic respiration – occurs when running, changes glucose molecules to produce only 2 ATP.

Eukaryotic cells evolved from prokaryotes.
Organelles – membrane bound compartments with specialized functions: Nucleus
Our metabolism depends on “enslaved bacteria” that does this process for us....
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