Module 4 - Biology

Evolution

the change in the organisms characteristics over time

Speciation

formation of new species, change in existing species

phylogenetic trees

display the evolutionary relationships of different species

What does evolution result in?

Huge diversity in all organisms on earth

What is fossil evidence?

Preserved remains or traces that can be dated back compared to other fossils. It demonstrates history of evolutionary change

Homologous structures

similar structure in closely related organisms

Do organisms go through the same basic developmental patterns?

Yes

Molecular evidence

comparing DNA in a gene, or a type of protein.

Do closely related species have more similar genes/proteins?

yes

what was the observation on Galapagos islands?

finches have different beak shapes depending on feeding habits

DNA of finches was compared:

Adaptive radiation - Finches descended from a common ancestor, with modifications that were adaptive for different food sources

Mutations

create changes and new traits in organisms

Natural selection

individuals with adaptive traits in an environment will survive and reproduce more frequently than those without. Population gradually evolves.

Sexual selection

individuals with traits that are advantageous for securing mates will out-reproduce those without

Artificial selection

Selective breeding, humans breed other plants/animals for particular traits

‘runaway’ sexual selection can result in extremes:

sex-related traits may be disadvantageous for survival

Isolating mechanism

prevents different species from cross-breeding

Geographic isolation

species are found in different areas, separated by a barrier

Ecological isolation

species are in the same area but occupy different habitats (Niches)

Temporal isolation

species reproduce in different seasons or times of the day

behavioral isolation

species have different mating rituals

mechanical isolation

Different species reproductive parts cannot fit together

Gamete isolation

gametes from different species are not able to come together (egg and sperm cannot fuze)

hybrid inviability (or sterility)

hybrids of different species are not able to survive or cannot reproduce (zonkey)

convergent evolution

independent evolution of similar traits in unrelated organisms

Ex: shark/dolphin - tapered body form, fins

Analogous structures

structures that are functionally similar but evolved independently

Ex: Wings for flight

Biological classification

categorizes organisms into groups (taxa) based on similar features

scientific name

specific names include genus then species

Biological classification changes as more information is gathered

Recent changes due to DNA technology

Bacteria:

Bacteria

Archaea

Archaea

Eukarya

protista, plantar, fungi, animalia

Kingdom bacteria

Unicellular prokaryotes and the most abundant organisms on the earth

Kingdom bacteria different features:

photosynthesis, nitrogen-fixation, have a flagellum

Kingdom bacteria relationship with humans:

pathogens - cause disease, symbiosis - benefit human hosts (gut bacteria), bioremedation - break down toxic compounds, food products

Kingdom archaea

Unicellular prokaryotes, ‘extremophiles’ - live in extreme conditions (hot, cold, salty, pH)

Kingdom protista

members of protista are very diverse, do not all share the same common ancestor = ‘catch all kingdom’

Features of different kingdom protista members:

outer cell walls, silica surfaces

may have cilia, one or more flagella

reproduce asexually or sexually

Unicellular, form colonies or multicellular

may be photosynthetic

Notable protists:

algae - food, agar

diatoms - have glassy shells

Paramecium - pond dwellers

Dinoflagellates - cause red tides

phytoplankton - base of aquatic food webs

Some protists cause disease

Giardia intestinal is (beaver fever)

Trichomonas vaginalis (trichommoniasis)

plasmodium (malaria)

amoeba sp. (encephalitis, gastroenteritis)

toxoplasma gondii (toxoplasmosis)

fungi kingdom features:

reproduces sexually and asexually

often use spores to disperse

yeast reproduce by budding off

notable kingdom fungi:

mycorrhizal fungi - symbiosis with plants

Lichen - symbiosis with an alga

Yeast - fermentation

penicillium fungi - antibiotics

virus

an acellular infectious particle that is an obligate parasite

Basic structure of viruses:

genetic material (RNA or DNA) surrounded by a protein coat (capsid)

naked virus - no phospholipid envelope

Eveloped virus - phopholipid envelope surrounding capsid

cytopathic effects

virus induced damage to cells

Where are viruses alive?

metabolism - no

cells - no

DNA - yes

replication - no

evolution - yes

lytic cycle

virus infects cell, replicates and destroys infected cell

lysogenic cycle

virus infected cell, pastes DNA into hosts genome, is copied with entire cell

Rhinovirus

causes common cold

influenza

causes flu

HIV

Leads to AIDS

HPV

produces warts

hepatitis B

liver inflammation

ebola virus

cause hemerrohagic fever