major events in the history of earth - san diego miramar ...faculty.sdmiramar.edu/bhaidar/bio 107...

Major Events in the History of Earth Cenozoic

Humans

Land plants

Animals

Multicellular eukaryotes

Single-celled eukaryotes

Origin of solar system and Earth

1

2

4

3

Proterozoic eon

Archaean eon

Atmospheric oxygen

Prokaryotes

Classification systems 5 Kingdom system 3 Domain system 1. Monera 1. Bacteria 2. Archaea 2. Protista 3. Eukarya 3. Fungi 4. Animalia 5. Plantae

Prokaryotes vs. eukaryotes Unicellular vs. multicellular

autotrophic vs. heterotrophic

Symbiotic relationships between any two organisms: 1. commensalism one organism benefits and the other is

unaffected 2. mutualism both organisms benefit 3. parasitism one organism benefits and the other one is

harmed.

Bacteria - Very diverse - Unicellular prokaryotes (lack a nucleus) - Three basic shapes: Bacillus, coccus, spirillum - Some are filamentous - Have a complex cell wall - Some autotrophic (Phototrophic or chemotrophic) others

heterotrophic - Found everywhere. Many live as symbionts in other

organisms

Protista Bottom–dwellers: attached or creeping Drift passively near the water surface (plankton) Phytoplankton - photosynthetic (planktonic algae and

cyanobacteria) form the foundation of most marine and freshwater food webs

- free–living species Zooplankton- Protozoa - heterotrophic

Eukaryotic- Protista • Majority unicellular • Multicellular – seaweed,

kelp • Cell wall present or

absent • Vary in cell wall

composition: o Silica (glass) o Calcium carbonate

(limestone) o Cellulose

• Vary in energy source o Photosynthetic –

Euglena o Heterotrophic –

Amoeba & Paramecium

Parasitic pathogens: • Giardia • Malaria

Amoeba

Euglena

Paramecium

Diatoms

Volvox

Early aquatic photosynthetic organisms : - Prokaryotic Cyanobacteria - Eukaryotic algae Unicellular Chlamydomonas Multicellular Spirogyra

Cyanobacteria filamentous photosynthetic prokaryote

Spirogyra filamentous photosynthetic algae, pond scum

Fungi Eukaryotic decomposers (heterotrophic) found in many

environments - saltwater or fresh water - on land - cold or warm temperatures Serve as a valuable ecological function by processing dead

organic matter Unicellular (yeast) Multicellular filamentous (mold) Parasitic pathogens:

Fungi evolved from an aquatic, flagellated ancestor A fungus usually consists of a mass of threadlike

hyphae called a mycelium

Hypha

Mycelium

Fungi absorb food after digesting it outside their bodies and absorb the nutrients

Fungal life cycles include asexual and sexual stages ASEXUAL - Haploid spores give rise to multi-cellular filamentous haploid hyphae by mitosis - The haploid hyphae are made of mating types

Fungal groups differ in their life cycles and reproductive structures Key

Haploid (n) Heterokaryotic (n + n) Diploid (2n)

Fusion of nuclei

Meiosis

Mycelia of different mating types

Cells fuse

Young zygosporangium (heterokaryotic)

Zygosporangium (n + n)

Sporangium Spores (n)

1

2 3

4

SEXUAL in fruiting bodies - Fusion of haploid hyphae produces a

stage containing nuclei from two parents heterokaryotic hyphae

- Nuclei fuse and undergo meiosis which

produces haploid spores

Fungal groups have characteristic reproductive structures

Key Haploid (n) Heterokaryotic (n + n) Diploid (2n)

Fusion of nuclei

Meiosis

Basidia Spores (n) Mushroom

1 Fusion of two hyphae of different mating types

2 Growth of heterokaryotic mycelium

3 Diploid nuclei

4 Spores released

5 Germination of spores and growth of mycelia

Lichens consist of fungi living mutualistically with photosynthetic organisms

Lichens consist of algae or cyanobacteria within a fungal network

Fungal hyphae

Algal cell

Col

oriz

ed S

EM

1,0

00 ×

Early land photosynthetic organisms Lichens- symbionts of a fungus and a

photosynthetic organism either a cyanobacteria or an algae

The photosynthetic algae or bacteria provide

organic compounds which the fungus can use and the fungus provides support and protection for either the algae or the bacteria.

Lichens can be found in the harshest of

environments on rocks