Mesozoic/ cenozoic - cretaceous paleogene period boundary
the end cretaceous mass extinction event caused by long standing volcanism from the Deccan traps
cenozoic - paleogene period - paleocene epoch
the abundant opens niches in earths ecosystems allowed for the major radiation of mammals and of the last dinosaur lineage. The birds. eventually, mammals become the dominant and large terrestrial animals on earth
cenozoic - paleogene - eocene epoch
angiosperms continue to dominate the land. Most present day mammalian orders are established including early primates
cenozoic - paleogene period- oligocene epoch
continued radiation of mammals including early ungulate ( hoofed mammal) groups.
cenozoic - neogene period - miocene epoch
mammals and angiosperms continue to dominate the land. The first apes including ape like ancestors of humans evolve
cenozoic - neogene period - Pleistocene epoch
the most recent glaciation events, the ice ages occur. The Pleistocene megafauna, extremely large mammals dominate the landscape but will mostly become extinct
cenozoic - neogene period- pliocene epoch
first fossil evidence of the genus homo , ancestors of humans
cenozoic - quaternari period - holocene epoch
the current geological time characterized by the end of the last major glaciation and the terrestrial dominance of Homo sapiens
what is gram staining
Formal classification of bacteria has undergone significant changes in recent years based
on molecular evidence. Historically, bacteria were primarily identified based on the
structure of the cell wall as indicated by the result of a Gram stain procedure. This stain
technique was developed in 1884 by Christian Gram, a Danish physician.
Using this technique, bacterial cells can be stained Gram Positive (Gram +) which is a
purple colour, or Gram Negative (Gram -), which is a red colour. Bacterial cells that are
Gram positive have a cell wall that contains a large amount of peptidoglycan, a protein-
carbohydrate polymer. Bacterial cells that are Gram negative have less peptidoglycan in
their cell walls which are also protected by a second, outer membrane. One major group
(Gram Positive Bacteria) is still identified by this feature.
Prokaryotes are
classified into two large groups or domains:
Domain Archaea and Domain Bacteria.
Organisms which belong to Archaea,
protists are
Protists are Eukaryotic cells (membrane-bound nucleus).
Many are unicellular (but not all)
plant like protists
carry out photosynthesis
Some are “fungus like”
(have thready structures used to
break down and absorb nutrients)
Some are “animal like”
(like us, they have to eat other
things and have structures that make them mobile)
Some act like animals sometimes
but can carry out
photosynthesis (mixotrophs)
chorophyta
Autotrophs (photosynthesis – chloroplasts)
* Is a mixotroph (auto and hetero)
-Cells have eyespots, which enable the colony to
swim towards light.
* Found in freshwater
Euglenozoa
- Unicellullar
- Flagellum at anterior end
- Autotrophs (photosynthesis –
chloroplasts) - Heterotrophs (ingest food)
- Mixotroph
- Eyespot called stigma (photoreceptor)
- plant and animal like
Ciliophora
Paramecium
- Unicellular
- Cilia (locomotion and feeding).
- Two types of nuclei: a large macronuclei and a
smaller micronuclei - Heterotrophs (consume bacteria and other protists)
Note: Oral groove on Paramecium. - Usually reproduce asexually (binary fission)
- animal like
Amoebozoans
- animal like
Unicellular - Lobe-shaped pseudopodia
- Movement – cytoplasmic streaming
- Heterotrophs - seek out and consume bacteria
and other protists. - A medically important group: Entamoebas
(parasitic , cause >100,000 deaths globally)
Cocci (
bacteria that are round shaped
Bacill
bacteria are rod-shaped and can occur either single or in
chain-like groups.
Spirochaetes and spirilla
are both spiral shaped bacteria. Spirilla are rigid and
spirochaetes are flexible.
procedure for making a wet mount
- Take a glass slide and cover slip.
- Using a plastic pipette, place (in center of your slide) a drop of liquid from the
specimen dish labeled Aquarium Filter Sludge. - Place cover slip onto drop.
- Examine under your scope.
permanent slides
also called permanent mounts, these contain material which is
dehydrated, stained and mounted in a plastic compound. Permanent slides last for
many years.
