1. Chapter 4 Lecture Slides
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2. Fundamentals of Biology
Chapter 4
Fundamentals of Biology

3. Types of Organisms
All living organisms can be divided into two basic groups based on cellular composition:
Prokaryotic
Eukaryotic

4. Types of Organisms Prokaryotic Organisms: Lack a nucleus
Posses ribosomes
Contain a circular ring of DNA
Some may also have plasmids, extra pieces of DNA
Cell wall is normally present
May have a flagellum
Unicellular

6. Types of Organisms Eukaryotic Organisms
Possess DNA enclosed inside a nucleus
Posses many specialized organelles (look at organelles in Fig. 4.8)
Eukaryotic organisms can be unicellular or multicellular

8. Levels of Organization in Living Organisms
Atom – fundamental unit of all matter
Molecule – two or more atoms chemically joined together

9. Levels of Organization in Living Organisms
Organelle – specialized features of cells
Cell – basic unit of life

10. Levels of Organization in Living Organisms
Tissue – group of cells functioning as a unit
Organ – many tissues arranged into a structure with a specific purpose in an organism

11. Levels of Organization in Living Organisms
Organ system – group of organs that work together
Whole organism (individual)

12. Levels of Organization in Living Organisms
Population – group of organisms of the same species occurring in same habitat

13. Levels of Organization in Living Organisms
Community – all species that exist in a particular habitat (ex: all the organisms on a coral reef)
Ecosystem – combination of the community and the physical environment

14. Diffusion and Osmosis
Solutes (substances dissolved in water) will move from areas where they are more concentrated to an area where they are less concentrated
This movement is called diffusion
Movement of water from an area where it is more concentrated to an area where it is less concentrated is called osmosis

16. Diffusion and Osmosis
Since marine organisms live in a very solute-rich environment, they have a tendency to gain solutes and lose water
This can result in the death of cells if the water loss/solute gain is significant
These organisms must find ways to deal with this diffusion and osmosis

18. Regulation of Solute/Water Balance
Osmoconformers-
Do not attempt to control solute/water balance
Their internal concentration varies as the salinity in the water around them changes
Most can only tolerate a very narrow range of salinity

19. Regulation of Solute/Water Balance
Osmoregulators
These organisms control their internal concentrations
Can generally tolerate a wider range of salinities than osmoconformers
This can be done in a variety of ways such as secreting very little urine or using specialized glands to secrete salts as examples

21. Temperature Control Ectotherms
Generate body heat metabolically, but cannot maintain constant internal body temperature
Examples: fish, reptiles

22. Temperature Control Endotherms
Generate body heat metabolically and body temperature does not match the temperature of the surrounding environment
Example:mammals

23. Modes of Reproduction Asexual reproduction
Does not involve mating of two individuals
Young are produce by a single parent organism
The young produced are genetically identical to the parent

24. Modes of Reproduction Examples of Asexual Reproduction
Fission – the splitting of one organism into two smaller organisms of equal size
Budding – the organism develops buds (small clones) that eventually break off and become another organism
Vegetative reproduction – a plant reproduces new individuals by sending an underground stem (rhizome) sideways from which new plants will sprout

25. Modes of Reproduction Sexual reproduction
Normally involves two individuals
Parent individuals produce gametes (eggs or sperm) that unite to produce a new, genetically unique individual
Ovaries are the organs that produce eggs
Testes are the organs that produce sperm

26. Modes of Reproduction
Many marine organisms release their eggs and sperm directly into the water, this is known as broadcast spawning.
For broadcast spawning to be effective, millions of gametes must be released into the water at roughly the same time to ensure fertilization will occur
Many broadcast spawning species time the release of their eggs to tides, moon phase, water temperature, etc. to ensure success

27. Modes of Reproduction
Other marine organisms rely on internal fertilization, where a copulatory organ is used to insert sperm directly into the female’s reproductive tract
This method requires contact between parent individuals, but less gametes are required for success

28. Evolution and Natural Selection
Evolution is defined as a change in the genetic make-up of a population over time
In the wild, any genetically derived traits (such as faster swimming or above-average intelligence) can give one individual survival advantage over others in his/her population.

29. Evolution and Natural Selection
These advantages can be translated into reproductive advantage as well.
If one organism is better survivor, more of their gametes will make it into the next generation in a population.
Those individuals that are less advantaged may not survive to reproduce or will reproduce less.
This is known as natural selection.

30. Evolution and Natural Selection
Natural selection therefore strengthens the gene pool of a species by eliminating less advantageous traits through lack (or reduction) of reproductive events in these individuals.

31. Taxonomy Taxonomy is the science of classifying and naming organisms.
This classification is done by a variety of methods including DNA and protein analysis, comparing embryos, looking at the fossil record and comparing internal and external body structures.

32. Taxonomy
Taxonomy uses several levels of classification shown below from the largest (most species inclusive) to the smallest (only one species):
Domain  Kingdom  Phylum  Class  Order  Family  Genus  Species

34. Phylogenetics
Phylogenetics is defined as the study of evolutionary relationships (relatedness) in organisms.
Biologists may use many factors to determine the relatedness of organisms such as structure, reproductive patterns, embryological or larval development, fossils, behavior or DNA/RNA.