Lecture 2 - Evolution and the domains of life

Question 1

What is taxonomy

Answer 1

Taxonomy: the way to classify groups

in biological systems

Question 2

what are examples of morphological

characteristics?

Answer 2

colour, pattern,

bones, organs

Question 3

What is the hierarchy of biological classification?

Answer 3

Domain
kingdom
phylum
class
order
family
genus
species

Question 4

What does evolution lead to?

Answer 4

both variation and unity

Question 5

explain homologous structures

Answer 5

Although forelimbs look very
different on the outside,
there remain similarities in
their skeletal structure
• Shared a common ancestor,
and different environmental
condition led to the
individual evolutionary
changes of each species
• After millions of years, still
retain core

Question 6

what were the first steps towards developing the theory of evolution?

Answer 6

aristotle - developed scala naturae “‘ladder of ife”, based on organisms function and complexity
Carl linnaeus - developed hierarchies based on morphological characteristics
-pioneered binomial nomenclature

Question 7

which theory of evolution did Aristotle and Linnaeus believe?

Answer 7

the doctrine of fixed species

Question 8

What did Jean baptiste lamarck develop? explain

Answer 8

the theory of lamarckian evolution.

• thought organisms traits could change throughout their lifetime through use and disuse
• thought these could easily be passes onto their offspring
• giraffes example

Question 9

what is good and bad about the lamarckian theory?

Answer 9

organisms traits can change throughout their lifetime, BUT it is very difficult to pass these traits onto their offspring.

Question 10

what did charles darwin develop?

Answer 10

he refuted the doctrine of fixed species

developed the theory of evolution by natural selection

Question 11

what aspects of evolution show unity?

Answer 11

homologous structures

for example

Question 12

what aspects show diversity?

Answer 12

• after an environmental change, physical traits may give a survival advantage
• example: antibiotic resistant gene in bacteria
• organisms in that environment are going to be selected for, but not necessarily in other environments without the selective condition

Question 13

what is the central dogma of evolution?

Answer 13

environmental change –> selective pressure overtime –> new species

Question 14

what determines physical traits?

Answer 14

• DNA contains genes, which encode proteins
• expression and activity of the proteins determine the structure and function of cells
• cells are the basic unit of life for all organisms
• cells can inherit or obtain DNA from other cells in a number of ways.

Question 15

how can cells inherit or obtain DNA from other cells?

Answer 15

conjunction/transduction
mitosis
meiosis
asexual + sexual reproduction

Question 16

describe the structure and function of cell membranes

Answer 16

• made up of lipid bilayers
• hydrophilic heads on outer and inner edges of the membrane
• hydrophobic tail in the middle of membrane
• is semi-permeable, and allows various nutrients, wastes, proteins and ions to pass in and out of the cell

Question 17

describe how cells utilise and store energy

Answer 17

• energy and matter flow from one organism to another using cellular respiration and photosynthesis
• one of the most common forms of energy is ATP
• ATP contains chemical energy in the bonds between its 3 phosphate groups.
• after breaking down nutrients, energy is converted to ATP.
• When ATP is broken down to ADP (one Pi removed), this energy can be released and used.

Question 18

state and describe the different types of cells

Answer 18

> prokaryotes
- lack of cell nucleus or membrane bound organelles.
- cytoplasm, cell wall, DNA, Nucleoid, Glycocalyx, ribosomes, flagellum, fimibriae, pilus, plasma membrane, plasmid
eukaryotes
- contains nucleus and membrane bound organelles.
- animal cell contains: cytoplasm, DNA, ribosomes, plasma membrane, plasmid, smooth and rough endoplasmic reticulum, nucleolus,chromatin, nuclear envelope, peroxisome, microvilli, centrioles, cytoskeleton element, lysosome, golgi apparatus, mitochondria

Question 19

what are the similarities between prokaryote and eukaryote cells?

Answer 19

> all have a plasma membrane
- encloses cell, separates contents from surroundings, phospholipid bilayer, 5-10nanometers thick, contains embedded proteins
cytoplasm
- semi-fluid matrix, contains chemicals of the cells, sugars, amino acids, proteins, contain organelles in eukaryotes
protein
- the work horsed, e.g., enzymes, structural proteins
carbohydrates
- energy source

Question 20

what are the differences between prokaryote and eukaryote cells?

Answer 20

• eukaryotic cells have their DNA inside a membrane
• eukaryotic cells have internal membranes that allow them to compartmentalise cellular processes.
• eukaryotic and bacterial cells are different in size
• eukaryotes = 10-100um in diameter
• prokaryotes = 1-5 um in diameter