Biodiversity: Ch 13 & 14 Test 2

Are the 3 domains of life all connected to one common ancestor?

What are the 3 domains of life?

Yes

1) Archaea

2) Bacteria

3) Eukarya

True or False:

Archaea and Bacteria are Sister Taxa

Explain

False

Archae and Bacteria both fall under Prokaryotes; they are NOT sister taxa

What are some of the characteristics of Early Life on Earth

- Anoxic & UV radiation= no oxygen and UV radiation was strong

- So, Deep ocean vents (pathways in volcanic interior chambers) and caves where there was not a lot of light were able to thrive (extremophiles) = therefore lineages of bacteria formed a niche in an inhospitable environment where they could live

- Microbial mats: biofilm of multiple layers of prokaryotes and obtained energy from ......

- Hypothermal vents: releases heated water (naturally)

What is formed as a result of microbial mats?

What is its purpose

Stromatolites

- serves as the microorganisms and home and offers protection

- coastlines dotted by green film

The Anoxic atmosphere in early life on earth supported what organisms? How?

anaerobic organisms

- because they do not require oxygen to survive

What role did the cyanobacteria play in early life on earth

- Cyanobacteria (blue-green algae)

- increased O2 in atmosphere

- O2- O3 = (ozone) --> abosrbs UV radiation

- aerobic respiration allowed for more efficient ATP production

- less radiation was hitting the earth's surface and more was being absorbed

What are the characteristics of Prokaryotes?

- no membrane bound organelles

- have ciricular chromosomes and plasmids

- have cell walls and capsules (most) = support and protection & attachment

- are asexual organism

- gram positive or gram negative

EXamples: Cocci, Bacilli, Spirilla

Whu are asexual organims problematic when studying their evolution? How do these organisms have variation as a result?

- they reproduce via binary fission and produce identical copies of themselves so there is no variatin or heritable traits

Solution:

horizontal gene transfer: organisms can exchnage chunks of DNA and integrate it into their own DNA and then pass it on via binary fission

What two characteristics of prokaryotes do we usually use to classify them? What is the difference between the two?

Gram positive & Gram Negative (describes peptidoglycan in cell wall)

Gram positive: thick layer of peptidoglycan around plasma membrane

Gram Negative: thin layer of peptidoglycan in between an extra outer membrane and plasma membrane

monophyletic clade

a taxonomic group that includes ALL of the taxa/species descended from a specific common ancestor

EX: archaea, bacteria, and eukarya

What is a biofilm?

microbial communities consisting of prokaryotes and sometimes fungi

- creates a film that is a mixture of secreted ORGANIC molecules that binds and protects the organisms in the community

EX: plaque on teeth, rust (microbes facilitate the rusting process by attaching themselves to wet metals)

Types of Prokaryotic Reproduction

What is special about prokaryote genome?

1) Binary Fission

2) Transformation

3) Transduction

4) Conjugation

genome is TINY

Binary Fission

duplicate circular chromosome and divide into identical daughter cells

-cloning

-no heritable variation

Transformation (reproduction) in Prokaryotes

- uptake of DNA in environment

- Free floating DNA in enviornment that is taken up and integrated into organism's DNA

Transduction Reproduction

-viral translocation from one prokaryote to another

- transfer of DNA from one prokaryote to another via the transmission of a virus

Conjugation

- DNA (usually a plasmid) transfer via contact with another prokaryote

- Horizontal Gene Transfer

TRUE OR FALSE:

most bacteria are pathogenic

False:

pathogenic bacteria are the exception

Zoonotic Disease

transmitted from non-human animals to humans

- process called zoonosis

- EX: corona

Pandemic vs Epidemic

EXamples:

Pandemic is a world wide spread of a disease and epidemic is a regional outbreak of disease (upper Midwest influenza outbreak)

EXamples:

Bubonic Plague: Epidemic

Botulism:

Salmonella

What are the two main causes of the ongoing antibiotic crisis?

1) Overused: Excessive use in Argiculture

- drives diversiification

- 70% of antiibotic use is found in agriculture

- used to enhance production, not prevent disease

2) Incorrect Use in Humans

- not finishing antibiotic

- exposes bacteria to antibiotic but does not eradicate them allowing them to develop a mutation that allows them to be resistant to antibiotic

EX: MRSA = resistant to strep throat

What are some of advantages of beneficial prokaryotes?

- Fermentation

- Bioremdiation

- Commensalism & Mutualism

- Digestion

- Competitors agaist pathogenic microbes

- Vitamin K production

- Training of Immune system: creates antibodies to recognize and fight off pathogens

Who proposed the Endosymbiotic Theory and what is the evidence for it?

Lynn Margulis in 1960s

- mitochondria and chloroplasts originated from prokaryotes

Evidence:

1) chloroplasts and mitochondria have their own unique circular DNA

2) roughly the same size as a prokaryotic cell

Hypothesis for endosymbiotic theory?

- infoldings of plasma membrane developed endomemebrane components including nucleus & ER

- Ancestral proto-eukaryotic cosumed aerobic bacteria that evolved into mitochondria

- early eukaryote consumed photosynthetic bacteria that evolved into chloroplasts

- altogether creating the modern photosynthetic eukaryote and modern heterotrophic eukaryote

What are Protists?

- microbial eukaryotes

- formerly a kingdom (Protista) but there are MULTIPLE origins within the kingdom

- usually unicellular

- some exceptions such as kelp

- have membrane bound organelles

- are NOT plants, animals, & fungi but INCLUDE eukaryotic ancestors to plants, animals, & fungi

Characteristics of Protists:

- live in aquatic/moist environments or are parasitic

- motile protist move by flagella, cilia, or pseudopodia

- feed via photosynthesis and/or phagocytosis (via food vacuoles)

- digest food in lysosomes and expel wastes via exocytosis

Phylogeny of Protsists

- there are 6 monophyletic clades

- there is uncertainty of relationships between the different clades

- such as Archaeaplastida & Opisthokonta

Pathogenic Protist

- transmitted to a secondary host such as humans

EXamples:

1) Malaria (Plasmodium falciparum) : from mosquitos to humans (however it would rather stay in the mosquitos so it can complete its life cycle)

2) Trypanosomes (Trypanosoma):

- African sleeping sickness transmitted by kissing bug

3) Downy & Powdery Mildew (Plasmopara viticola): devastated french winery in 19th century

4) Potato Late Blight (Phytophthora infestans): irish potato famine

Advantages of Beneficial Protists

1) conduct photosynthesis (25% of it)

- such as diatoms, dinoflagellates, & algae

- accounts for oxygen we breath

2) Zooxanthellae:

- mutualistic relationship with coral & give coral their color; coral reefs would collapse without them

3) Saprophytes:

- decompose organic matter

- dog vomit slime mold

- key part of global biogeochemical cycles

We can see the diversity of plants based on what?

1) Plant Kingdom: characterstics & terrestrial adaptations

2) plant divisions

3) plant reproduction

Plants are fall into what domain of life

Eukarya

What are archaeaplastida?

- clade that is derived from ancestral endosymbiosis of cyanobacteria

Plants within this clade are:

- red algae

- Green algae & land plants

- dominance of chlorophyll, cellulose synthesis, flagellated sperm

What is the difference between algae and land plants?

land plants retain embryos

What are the chracteristics of a plant?

ALL multicellular eukaryotes

- photosynthetic (unless secondarily lost)

- cell walls made of cellulose

- usually have apical meristems

the most abundant organic molecule on the planet is found in plants, what is it? How does it relate to evolution?

cellulose

- because cellulose is difficult to digest, it allows animals that eat plants to develop adaptations so they can digest it more easily

Apical Meristems

- collection of specialized cells of tissues arund the end points of the growing tips of plants

- specially evolved for rapid developing & growing which is indeterminant

- also assoicated with roots, shoots, and vascular tissue that are used to transport nutrients from soil to vegetative structure and distribute energy via photosynthesis

It is believed that all plants first lived in what type of enviornment before evolving and changing location?

originated in aquatic setting

Why do biologist believe plants moved on to land rather than staying in water?

1) abundance of sunlight (photosynthesis)

2) access to carbn dioxide (reactant in photosynthesis)

3) lack of predators (at the time)

- at the time there were mre predators in aquatic environment

What were some of the challenges that plants faced once invading terrestrial enviornments? What were their adaptations?

Challenges:

1) risk desiccation when out of water

2) needed a new way for structural support & be held upright

3) had to acquire nutrients

4) sexual reproduction

5) Herbivory (later on)

Adaptations:

1) tolerance & waxy cuticle(thick organic substance that encases surface of plant) , elaborate system of pores called stromata (open/close pores to release gas or retain it)

2) Cellulose & lignin (structure)

3) Roots and Vascular Tissue (acquire nutrients)

4) Pollen, seeds (dispersal), embryo retention (increases probability of development)

5) secondary metabolites: act as defense mechanism that act against herbivores such as thorns

What is the advantage and cost of plants growing tall

Advantage:

- optimal sunlight= higher rate of photosynthesis

Cost:

- have to get nutrients further away (from bottom to top)

- needs more energy because of size

- easily detected by predators

The land plants make up a class of plants called the ____________________?

embryophytes

1) The 2 major most broad groupings of plants are ___________________ & ____________________.

2) Vascular plants are then divided into ____________________ & ___________________

3) Seedless plants are then divided into _________________ & _____________

4) Seed plants are then divided into ____________ & ______________

1) vascular and nonvascular

2) seed & seedless vascular

3) Lycophytes & Pterophytes

4) Gymnosperms & Angiosperms

What are the nonvascular, seedless plants

Bryophytes

What are the characteristics of Bryophytes

- nonvascular, seedless

- consist of liverworts, hornworts, & true mosses

- lack vascular tissue

- limited to living in moist environment

- lack lignin: no structural support mechanism

- limited to horizontal grwoth patterns

- Achored by RHIZOIDS, no true roots

- Reproduce: sperm must swim to to egg cells following rain event

life cycle of bryophytes illustrates the _________________________ of ____________________

Alternation of Generations

In each cycle a haploid gametophyte alternates with a diploid sporophyte

Gametophyte Generation:

Gametophytes produce sperm and egg which fuse to form diploid zygotes that grow into sporophytes (the 2nd generation):

Sporophyte Generation:

- Zygote undergoes multiple rounds of mitosis giving rise to a diploid sporophyte

- specilaized cells of the sprophyte undergo meiosis and produce haploid spores

- the spores then develop into gametophytes & process begins again

Key Facts about Bryophyte Life Cycle

- the major vegetative component is the GAMETOPHYTE (can be male or female)

- the diploid portion is the sporophyte

- the haploid portion is the male & female gametophyte

Evolution of VASCULAR plants

- competition for sunlight favors tall growth

- vascular tissue is required for taller growth

- develop TRUE roots & leaves: support larger size & vascular system, anchors to ground, enables photosynthesis

- symbiosis with soil fungi= mycorrhizae

- associated with vascular plant roots

- provides nitrogen to roots of plants in a more efficient way than uptaking nitrogen from the soil

Types of vascular tissue in vascular plants

1) Xylem: water and mineral transport: roots to shoots pathway

2) Phloem: sugar & organic molecules: source to sink pathway ( take nutrients from leaves and transports them to roots for storage or use)

What are the two subdivisions of seedless, Vascular plants? Give examples for each division

1) Lycophytes: club mosses, quillworts, spike mosses

2) Pterophytes: whisk ferns, horsetails, ferns

Characteristics of lycophytes & pterophytes

vascular, seedless

- almost like an intermediate between nonvascular & vascular

- well defined leaves

- true root systems

- can be assoicated with bryophytes: (live in dark moist envirnments)

- dominant in carboniferous period- rich coal deposits

- water is still required for fertilization like bryophytes

life cycle of a fern

- Alternation of Generations

- primary vegetative structure is SPOROPHYTE

- sporophyte produces spores found on underside of leaves

- sporophyte is still diploid

- gametophyte is haploid (can be male or female)

- spores undergo meiosis, germinate, and develop into gametophytes

- sperm fertilizes the egg, develop zygote, and grows into leafy sporophyte

Evolution of Seed Plants

- pollen & seeds confer relative independence from water: enhances reproductive success & no longer need flagellated sperm to reach egg

1) Pollen grain: contain sperm cells & pollen tube

- designed for dispersal without water

- pollen reaches female portion of gymnosperm

- coevolve with dispersers

2) Seeds- contain embryo and nourishment w/ protective seed coat

Importance of seeds

- allow for dormancy and early development of embryos

- also coevolve with dispersers such as animals, wind, & insects

- want seeds to be dispersed away from parent plant so they do not compete for growth with their own species

True or False:

Pollen and Seeds coevolve with dispersers to enhance reproduction of plants?

True

What are the two subdivisions of Vascular, Seed Plants?

Gymnosperms & Angiosperms

What are the characteristics of gymnosperms

When does the seed form in gymnosperms?

-often called "naked-seed" plants

- nonflowering, usually cone bearing (cones contain pollen & egg)

- needle-like leaves, often evergreen

- pollen is dispersed by WIND: wing-like flaps branch off pollen grain so they can ride on wind and land on neighboring tree

the seed forms after pollination & fertilization:

- develops after fertilization

- seed is a diploid in developing plant

Whata re the two cone types of gymnsperms? Where are the male and female cones usually locate don the plant?

1) Staminate Cones:

- male cones

- contain microsporophyte generation: pollen plants

- pollen grains: haploid gamete structure

2) Ovulate Cones:

- female cones

- contain megasporophyte generation: contain eggs

**** Female cones located on upper branches and male cones are located on lower branches so that when the pollen blows in the wind, self-fertilization does not occur*****

What are some examples of Gymnosperms?

Pine trees, Cyad, Conifers (spruce, sequioa, juniper, tamarack, Ginkophyte, Gnetophyte

What are the characteristics of Angiosperms?

- vascular, seed plants

- flowering plants: the leaves are modified for reproduction

- Contain: Seeds & Fruit

3 key characteristics:

flowers, embryo retention/dormancy in seeds, & development of fruits

Role of seeds and fruits in angiosperms?

Seeds: contain embryo w/ food source

- allows for dormancy and germination

Fruits: protection & dispersal of seeds

- may contain secondary metabolites

Parts of an Angiosperm

1) Sepals: enclose & protect developing bud, carry out photosynthesis (leafy structure at base of each flower, usually occurs in pairs)

2) Petals: modified leaves; attract pollinators & contain color

3) Receptacle: base of flower

4) Stamens: male reproductive organs

- consist of anther and filament

- produce pollen grain: contain 2 sperm cells & pollen tube

5) Carpel: female reproductive organs

- consist of ovary, style, & stigma

6) Ovary

In angiosperms the _____________ __________ are within the ovule to produce the ___________________ after fertilization and the _______________________ are within the ovary to produce the ________________________

- eggs cells within ovule to produce seeds

- ovules are within ovary to produce fruits after fertilization

What is the function of the 2 sperm cells and pollen tube

- 2 sperm cells: responsible for fertilization of egg cells in ovule

- pollen tube provides the route for the sperm cells to go into the ovule

What are the two parts of the Angiosperm reproductive cycle? Describe them

1) Pollination: occurs when pollen grain is transferred to the stigma and then the style provides the pathway for the pollen grain to ovules within the ovary

2) Double Fertilization Event:

- pollen grain moves down stigma into style and into one of the ovules containing multiple egg cells

- sperm cells travel down the pollen tube into the ovules

- 1st sperm cell fertilizes egg

- 2nd sperm cell combines with the polar nuclei

Once the double fertilization event occurs in the angiosperm what is produced by the 2 sperm cells

- 1st sperm cell: fertilizes egg producing embryo

- 2nd sperm cell: combines with polar nuclei to produce an endosperm

- endosperm: triploid protective layer contained within seed coat of developing embryo (like yolk that nourishes embryo) & can lie dormant

Simple Fruit

Example: Pea fruit

- individual seeds contained within single ovule

Aggregate fruit

fruitlets: individual ovaries

- bunches of carpels as opposed to single carpel

- each fruitlet contains egg cells

EX: Rasberry

Multiple Fruit

- each segment considered an individual flower containing a carpel

- Example: Pineapple

Accessory Fruit

A fruit, or assemblage of fruits, in which the fleshy parts are derived largely or entirely from tissues other than the ovary

- ovules contained within ovary

- ovary contained within receptacle

- receptacle swells after fertilization

Example: Apple

what are the two mechanisms of fruits?

1) layer of protection for seeds

2) incentive for dispersal by animals

Methods of Dispersal of Fruits

1) Animals: such as squirrel burying seeds/fruits underground

2) Wind: dandelion (fruit)

3) Water: coconut

4) Mechanical function:

- fruit of puncture vine (sandspurs)

- seeds in black bear feces

- ant carrying seed with attached "food body"

What is a monoecious plant? How does it avoid self-fertilization?

- contains male and female component within a single flower

- prevents self-fertilization through embryo inviability

dioecious plants

- seprate male and female plants

- contain only 1 of the 2

What ar ethe easily observed characteristics that can distinguish monocots from eudicots. List the characteristics for each

1) Veins in leaves

2) Flower parts

Monocots: parallel veins and three or multiples of 3 flower parts (petals)

Eudicots: branched network of veins & four, five, multiples of 4 or 5, and whorls flower parts

Exceptions to characteristics that distinguish monocots and eudicots

flowers can lose petals/sepals due to environmental conditions

Example of Biocontrol with Tamarisk and Salt Cedar

Salt Cedar:

- angiosperm native to old world (Eurasia & Africa)--> looks like a gymnosperm

- introduced to N. America and invasive in southwest

- can out-compete neighboring vegetation by making enviornment in inhospitable for all plants but itself through secretion of salts

Tamarisk Beetle:

- Biologist released Tamarisk beetle to fight invasion of salt cedar

- ate leaves, laid eggs, etc and regulated the population size of salt cedar

- however the pathway backfired and the beetle started invading native plants

What is the biggest issue with biocontrol

- pathways can sometimes backfire so it is usually used as a last resort/nuclear option for wildlife management