plbi 327 midterm

Charles Darwin

English natural scientist who formulated a theory of evolution by natural selection (1809-1882)

What are the four main points of Darwin

1. Variation is random in a population

2. Traits can be inherited from progenitor to progeny

3. Some traits are better than others

4. More fit traits survive, assumes the existence of competition

Evolution by Natural Selection is the only possible outcome

Thomas Malthus

Eighteenth-century English intellectual who warned that population growth threatened future generations because, in his view, population growth would always outstrip increases in agricultural production.

Carrying Capacity guy

carrying capacity

Largest number of individuals of a population that a environment can support

Limited resources limits population growth

Macroevolution

large-scale evolutionary changes that take place over long periods of time

Microevolution

Change in allele frequencies in a population over generations.

Speciation

the formation of new and distinct species in the course of evolution.

allopatric speciation

The formation of new species in populations that are geographically isolated from one another.

Ex: Seperated by a river

sympatric speciation

The formation of new species in populations that live in the same geographic area

ex: active at different times of day

parapatric speciation

speciation pattern in which populations speciate while in contact along a common border

geographically adjacent, but at the edge of a niche

Ecologically isolated and not reproductively isolated

Polyploidy

A chromosomal alteration in which the organism possesses more than two complete chromosome sets.

Polyploidy in plants

tend to be bigger and stronger than diploid plants

self-fertilization

When pollen fertilizes eggs from the same flower

4n

tetraploid

normal meiosis

1 of each chromosome in gamete

Advantages of polyploidy

- More chromosomes so larger cell nuclei → larger cells → larger leaves, stems, fruits, flowers etc.

- May allow plants to grow in a wider array of habitats and be more resistant to pests and diseases

Non-disjunction in Meiosis I

Homologous chromosomes fail to separate

only meiosis 2 occurs normally

-result in 2n + 2n

Non-disjunction in Meiosis II

Sister chromatids fail to separate

meiosis 1 occurs as normal but

-result in 1 2n and 2 1n

Heterosis (hybrid vigor)

ability of offspring to out perform the average of the parents breed

2x the dna with polyploidy

Negatives of polyploidy

issues with meiosis and mitosis

extra dna takes up a ton of space

Autopolyploidy

an individual that has more than two chromosome sets that are all derived from a single species

multiplication of the genome within ONE SPECIES

auto = same

allopolyploidy

polyploidy resulting from contribution of chromosomes from two or more species

Hybridization between two or more DIFFERENT SPECIES

allo = different

Carl Linnaeus

"Father of Taxonomy"; established his classification of living things; famous for animal naming system of binomial nomenclature

binomial system

Identifying organisms by their genus and species names

Taxa

group or level of organization into which organisms are classified

phylogeny tree

branching diagram showing relationships among different species or groups

Clade (monophyletic group)

A group of species that includes an ancestral species and all its descendants. -> CLADE

terminal taxa

The species being investigated

monophyletic

ALL descendants came from one common ancestor

paraphyletic

Pertaining to a group of taxa that consists of a common ancestor and some, but not all, of its descendants.

polyphyletic

pertaining to a group of taxa derived from two or more different ancestors

algae is a good example of this. primarily a human classification issue.

LUCA

Last Universal Common Ancestor. The shared ancestor that multiple organisms diverged from

cladograms KNOW HOW TO MAKE THESE.

a branching diagram showing the cladistic relationship between a number of species.

LOWEST NUMBER OF CHANGES

Prokaryote

A unicellular organism that lacks a nucleus and membrane bound organelles

hadean

Pre Cambrian. Before Archezoic. Rockless, formation of Earth, solidifying crust

hell. The first life.

anaerobic enviorment

First life

3.5 bya. it was Archea and Bacteria

cyanobacteria

Bacteria that can carry out photosynthesis

hadean extinction event

exterminated anaerobic bacteria and ended up raising O2 levels, this was bad for them and they couldn't handle it and they died.

banded iron formations

alternating bands of iron oxide and chert some of which date to as early as 2.5 bya (used as evidence for an oxygenated atmosphere during Precambrian time)

Chloroflexus

green nonsulfur bacteria

Anoxygenic photosynthesis - no O2 production

principle of parsimony

the belief that explanations of phenomena and events should remain simple until the simple explanations are no longer valid

what did mosses develop taxonomically (bryophyte)

embryos

what did ferns develop after moss (Tracheophyta)

xylem and phloem

what did pines develop after ferns (gymnosperm)

wood and seeds

what did oaks develop after pines (angiosperm)

flowers

make a simple cladogram of land plant taxonomy

ez

Cyanobacteria dna transfer

Cyanobacteria share a lot of dna between each other and they have easy transformation. (encorporate floating pieces of dna they find)

Cyanobacteria morphology

-filaments, spheres, spirals

-individual cells, chains or colonies

Unicellular. Binary fission. No sexual stage. Mucilaginous.

mucilagenous sheath

jellylike layer often surrounding cyanobacteria

what is the mucilaginous sheath made of

glyoaminoglycans, otherwise known as mucopolysaccharides

glyoaminoglycans

Glycosaminoglycans (GAGs) are a group of polysaccharides that are found in the body's tissues and cells.Also known as mucopolysaccharides.

What is the function of the Mucilagneous Sheath

It helps the cell not dry out.

important for water retention.

can also help with buoyancy.

can help to deter herbivores. (covered in gel is not appetizing)

They can provide UV protection (Important because there was no ozone layer at the time!)

Nostoc (cyanobacteria)

Genus and type of bacteria

Very large balls

chained organism

filaments of cyanobacteria are called

trichomes

filaments of cyanobacteria exists because

error in mitosis kept them fused together after binary fission

it was an error at first but it's not STILL an error, it's intentional now.

filaments in cyanobaxteria are primative ___________

plasmodesmata

Plasmodesmata

An open channel in the cell wall of plants through which strands of cytosol connect from adjacent cells

Resting spores

Spores with a thick wall that protects the contents during adverse conditions. The spores only germinate after a period of dormancy, when the conditions have improved.

Some cyanobacteria make these

heterocyte

A specialized cell that engages in nitrogen fixation in some filamentous cyanobacteria; formerly called heterocyst.

Thick walls. Nitrogenase doesn't like water.

look like glass balls

Oscillatoria (Cyanobacteria)

long filament of cells; photoautotrophs; cyanobacteria

form structures called hormogonium

how Oscillatoria change their morphology based on programmed cell death

Hormogonium

A short motile chain of three to five cells produced by filamentous cyanobacteria to disseminate their cells.

important for asexual reproduction.

cell-cell adhesion

binds cells into tissues/organs

cell specialization/differentiation

The process by which cells change as they grow and develop to become specialized with different functions.

how does cyanobacteria reproduce

Totally asexually. Binary fission. They have circular chromosomes

what kind of chromosomes do cyanobacteria have?

circular chromosomes

Cyanobacteria reproduction

binary fission, budding, fragmentation, multiple fission

what does the hormogonium do

The trichomes (filaments) of cyanobacteria break into hormogonia at regular intervals.

Each hormogonium is a short piece of filament that contains 5-15 cells.

The hormogonia glide and develop into new filaments.

separation disk

Note the separation discs in the uppermost filament: these are formed by the death of cells at intervals along a filament, the dead cells filling with mucilage. Filaments will eventually fragment at these separation discs into separate segments called hormogonia or hormogones, a form of asexual reproduction

algal bloom

The rapid growth of a population of algae

Stromalites

layered rocks that form when certain prokaryotes bind thin films of sediment together

USED TO BE CYANOBACTERIA

Endosymbiosis

A theorized process in which early eukaryotic cells were formed from simpler prokaryotes.

Phagocytosis

A type of endocytosis in which a cell engulfs large particles or whole cells

origin of chloroplasts

Cyanobacteria (photosynthetic prokaryotes) contain chlorophyll and enzymes similar to chloroplasts

Theory of Endosymbiosis Chloroplasts are the descendants of cyanobacteria that were engulfed by eukaryotic cells about 2 billion years ago

They lived in symbiotic relationship within the cells that had engulfed

Over time, the cyanobacteria became permanent residents of the cells and progressively changed

secondary endosymbiosis

a process in eukaryotic evolution in which a heterotrophic eukaryotic cell engulfed a photosynthetic eukaryotic cell which survived in a symbiotic relationship inside the heterotrophic cell

membrane counts

Green Algae have 2 membranes

Red Algae have 2 membranes

Brown Algae have 4 membranes

Diatoms have 4 membranes

Euglenoids have 3 membranes

Draw primary and secondary endosymbiosis

yes yes do this (primary and secondaru endodymb)

Misconceptions: In a 3 domain tree, all 3 are equally related

NOT TRUE: Archaea and eukarya are more closely related

Misconception: Not all eukarya are related to archaea

NOT TRUE: All eukarya are related to the common ancestor of archaea

Are cyanobacteria considered algae?

NOPE! Algae are protists.

protista is a ______________ group

polyphyletic

what are some examples of protists

algae, protozoa, slime molds, water molds

What trophy are protists?

they can be photosynthetic autotrophs, or heterotrophs or a mic between them.

Glaucophytes

Unicellular freshwater algae with chloroplasts containing traces of peptidoglycan, the characteristic cell wall material of bacteria.

RETAIN BACTERIAL CELL WALL (in the chloroplast)

Discoba

Protist supergroup of unicellular flagellates; often with feeding groove and uses phagocytosis to ingest food; disc-shaped mitochondrial cristae

Stramenopila

A diverse protistan clade that includes several heterotrophic groups and a variety of photosynthetic protists.

Dinoflagellates

Group of protists that form "blooms", can be toxic. make up phytoplankton and can be bioluminescent. They generally have two flagella, half are heterotrophic and the other half are photosynthetic, many species are luminescent

Dinoflagellates (Alveolates)

photosynthetic unicellular alveolate protist with two flagella, one that it uses to spin itself for locomotion and one that it uses to steer; many of them are luminous in water and they are the cause of toxic red tides in oceans that can be deadly for marine life

Eugelnoids

unicellular

terminal flagellum

no cell wall

contain chloroplasts with chlorophyll

eyespot can receive light

contractile vacuole to regulate water

do euglenoids have a sexual stage?

No. they do not have a sexual stage.

Longitudinal division

the cell never divide in a transverse manner, always longitudinal (always down the long end of the cell)

metaboly

the change in shape of euglena when it can't swim freely due to the flexibility of the euglena pellicle

Biological process that describes the abillity of a cell to change shape

To catch prey.

Relationship between metaboly and heterotophic

More metaboly = more heterotrophic

paramylon

The storage molecule of euglenoids

Plastids

A group of membrane‐bound organelles commonly found in photosynthetic organisms and mainly responsible for the synthesis and storage of food.

nucleomorph

tiny vestigial nucleus.

this happens in some secondary and tertiary endosymbiosis cases but most of the time you lose the mitochondria and nucleus.

sometimes you even lose a membrane

Normal outcome of secondary endosymbiosis

4 membranes

1. original cyanobacteria membrane

2. primary endosymbiosis membrane (from host cell 1)

3. New phagosome from ancestral host cell #2

4. ancestral host cell outer membrane

Pellicle

A firm, flexible coating outside the plasma membrane

proteinaceous plates

made of proteins called articulans - non-polar amino acids

articulans

connected via microtubules, they can get longer and shorter. LIKE A SUIT OF ARMOR.

An Endo exoskeleton