Biology 1114 Final- Calinger

Morphological Concept

Same species share more similar characteristics with each other than different species because of longer shared evolutionary history

Genetic Species Concept

Species share more similar DNA than other species because of longer shared evolutionary history

Ex: Forest and Savannah elephant DNA is as different as Asian elephants and wooly mammoths

Biological Species Concept

Species are groups of organisms that can interbreed and produce fertile offspring and are reproductively isolated from other species

What links all three species concept?

Members of the same species linked by shared evolutionary history via ability to exchange genetic information

Speciation

The process by which populations attain reproductive isolation

Reproductive isolation

biological barrier impedes members of different species from interbreeding and producing viable, fertile offspring

Pre-zygotic barrier definition

Prevents mating or fertilization (if mating occurs)

(physically cannot have sex or gametes cannot combine)

Example of Pre-Zygotic barriers (5)

1. Gamete isolation (length of reproductive tract or shape or length of sperm)

2. Morphological Differences (genital prevent mating)

3. Temporal Isolation (different timing)

4. Behavioral differences (different courtships or mating signals)

5. Habitat Isolation (breeds in different habitats; mosquitos)

Post-zygotic barrier definition

Prevents hybrid offspring of two species developing viable, fertile adults

Post- zygotic examples

Reduced variability: hybrids either fail to develop or are very frail and unlikely to survive

Donkey + Horse = Mule (infertile)

Allopatric Speciation

Gene flow prevented by geographical isolation

Can occur vicariance or dispersal

Vicariance

Population split by the formation of a geographical barrier

Ex: Grand Canyon

Dispersal

Distance as a result of movement to new areas results in reproductive isolation as populations are no longer continuous

Ex: Hawaii Islands

Parapatric Speciation

Geographically continuous over vast distances

No physical barriers

Individuals at either end functionally isolated and they often experience different environmental pressures

Ex: Salamanders/California example

Sympatric Speciation

Occurs in populations that live in the same geographical area

Most important more speciation for plants

Punctuated Equilibrium

Rate of Speciation Model (1)

RAPID burst of speciation the followed by little changes

Gradual Model

Rate of Speciation Model (2)

Species diverge gradually over time (steady)

small incremental changes

Adaptive Radiation

Period of evolutionary change in which organism form many new species with adaptations specialized to different niches

When does adaptive radiation occur?

Often after mass extinction or when new areas are colonized

(adapts to new niche)

Niche

specific biotic and abiotic resources used by a species

Competitive Exclusion

No two species will ever co-exist EQUALLY and be perfectly equally successful at utilizing a resource so more successful competitor will exclude the other from the niche

Inferior competitor will either go locally extinct or utilize different resources

Resource Partitioning

Similar species can coexist in an area IF they use different sets of similar resources or the same resource at different times or seasons

Sharing is caring

How old is Earth?

4.6 billion years old

How long has life been on Earth?

3.5 billion years

Mass Extinction

Rapid decline in large number of species

MUCH higher than background extinction rate

Permian Mass Extinction

Extreme volcanic activity size of half western Europe covered with lava, hundred of meters thick

CO2 increase atmospheric temperature to 6 deg. C

~90% of all species went extinct

Cretaceous Mass Extinction

End of Dinosaur Era

Earthquake 1000x stronger than atomic bomb, 400 km winds, oceans boiled, and forest in N. and S. America flattened by shockwave

Carbon and Sulfur cooled atmosphere followed by acidic showers

Increase in CO2 levels

Highly Conservative

Only includes species classified as extinct

Conservative

includes species classified as extinct, extinct in the wild, and presumed extinct

Early "proto" cells

1. Lipid bilayer spontaneously forms vesicles

2. Early conditions on Earth allows synthesis of amino acids (various gases)

3. RNA strands form spontaneously when dripped onto hot substrate (rock, sand etc.)

4. RNA as ribozyme allows replication of RNA within cells (biochem)

Prokaryotes

Lack membrane organelles and a membrane-bound nucleus

Domain Bacteria and Archaea

Eukaryotes

Have membrane-bound organelles and a mebrane bound nucleus

Protists, fungi and animals

Prokaryotic Characteristics

1. Smaller genomes than eukaryotes

2. Circular chromosomes

3. Plasmids independently replicating (antibiotic resistance)

4. Similar gene translation to eukaryotes but small ribosomes

5. Reproduce by binary fission (splitting one cell into two identical)

How do we kill bacterial cells without killing our own cells? (antibiotics)

1. Prevent bacteria from making cell wall

2. Disrupt small bacteria ribosomes that make protein needed for bacteria to live

Gut bacteria

secretes horomones that influence the enteric nervous system

varies depending on gut flora

ex: can change the way we interact with our food choices

Archaea

Single-celled prokaryote

Lovers of "extreme conditons"

Characteristic: Nuclear Envelope

Bacteria: Absent

Achaea: Absent

Eukarya: Present

Characteristic: Membrane Closed Organelles

Bacteria: Absent

Archaea: Absent

Eukarya: Present

Observation about mitochondria and chloroplast

1. Both have own lipid bilayer

2. Both have circular DNA that can replicate independently

3. Both have their own ribosomes that are smaller than ribosomes in the cell which they live

4. Both reproduce by splitting process similar to fission

Endosymbiont Theory

Mitochondria and chloroplast derived from ancestral prokaryotes that were "engulfed" by the cell

Relationship became symbiotic

Protists

a group of "mostly" unicellular organisms that are not fungi, plants or animals

We dont understand them; phylogenies are constantly changing as we add data and knowledge

MOST eukaryotes are protists and most protists are unicellular!!!!!!!!!!!!!!!! (we just cant see them)

NOT VALID EVOLUTIONARY GROUP because does not include most common ancestor and all descendants

Holdfast? Blade? And Stipe?

Aquatic life adaptations

Roots, leaves and stem

Very similar to plant structure but the DNA analysis indicated they arose from entirely different evolution lineages

Brown algae and Carotenoids are an example of what type of evolution?

Convergent evolution: similar structures but different lineages

Closest relatives to land plants?

Red and green algae

Photosynthetic protists

Feature of green algae

1. Often live in intertidal zones: someone submerged, sometimes not

2. Zygotes coated with sporopollenin: tough polymer that prevents desiccation (extreme dryness)

3. Flagellated gametes: "swim" to each other

4. No internal structural support: supported by water

Major challenges for movement onto land from water

1. Must be able to avoid desiccation (extreme dryness)

2. Must develop supportive tissue to remain upright (compete for light)

3. Need to have gametes that don't require water to swim and achieve fertilization

Benefits of early life on land

1. Unfiltered sunlight

2. Higher CO2 concentrations than in water

3. Fewer herbivores and pathogens (during initial colonization)

4. Nutrient rich soils and increase photosynthetic efficiency

derived traits that unite land plants but are absent in green algae

1. Alternation of generations

2. Multicellular, dependent embryo

Describe the plant reproductive cycle

1. Spore (haploid reproductive cell, n) goes through mitosis to turn into a gametophyte

2. Gametophyte (haploid multicellular organism, n) makes gametes via mitosis

3. Two gametes (haploid reproductive cell, n) join making a Zygote via fertilization

4. Zygote (diploid, 2n) makes sporophyte (diploid multicellular organism, 2n) via mitosis

5. Sporophyte makes spore via meiosis

Bryophytes

non-vascular plants

tend to be small and live in moist environments and lack vascular tissue

flagellated sperm

GAMETOPHYTE (haploid generation) IS THE DOMINATE GENERATION

Xylem

Transports water from root to shoot

Phloem

transports sugar formed via photosynthesis from leaves to the rest of the plant

Seedless vascluar plants

Ferns: first plants to grow tall

Sperm is still flagellated

BUT SPOROPHYTE IS THE DOMINATE GENERATION

Seed Plants {key differences from seedless}

Gymnosperms and Angiosperms

1. Extremely reduced gametophytes

sheltered from UV radiation and ground

by parental sporophyte tissue

2. Ovules and Pollen

Megaspore: female gametophyte

Integument: layer that protects sporophyte

tissue and developing embryo

Microspore: develops into pollen grain (male

gametophyte)

3. Seeds

initiated by pollination

Benefits of pollen delivered over flagellated sperm

1. MUCH greater distribution

2. No water

3. Can be transported by animals or wind

Three Generations in a single seed?

1. Sporophyte embryo

2. Food supply

3. Seed coat

Differnces between spore and seed (4)

Size:

Spore- single celled

Seed- multicellular embryo

Protection post-dispersal

Spore- NONE

Seed- Seed coat from integument

Post dispersal resource supply

Spore- NONE

Food supply from female gametophyte

Dormancy

Spore- relatively short

Seed- Up to hundreds of years (sometimes

thousands

Gymnosperms

"NAKED"

No fruit

often come in cones (pine cones)

Dispersal: WIND

No adaptation for pollinator attraction, produce mass clouds of pollen

Angiosperms

Flowers and fruits

90% of all known plant species

Sexual reproduction

4 modified whorl structures

1. Sepal (protection)

2. Petals: (Attractive)

3. Stamen: (anther and filament, male, pollen producer)

4. Carpel: (stigma, style, ovary, female, pollen acceptor)

Dispersal Strategies

1. defecation

2. wind

3. animal

4. explosive seeds

How do herbivores act as a selective pressure

-eats holes in leaves (less surface area, less photosynthesis, still functional)

- eats flower, (less attractive)

-eats flower, (loss of reproductive structures)

-loss of nutrients stored in tissues

Fungi

lives as decomposers, parasites or mutualist

fun fact: all mushrooms can kill you lol

Characteristics of fungi

1. Heterotrophs: feeds by breaking down compounds outside body

2. Hyphae: tiny filaments surrounded by cell walls of chitin

singled cell fungi is called yeast

Chytrid

Massive global amphibian decline

Fungal infection (unicellular parasite)

Burrow into amphibian skin

Fungus increases due to climate change (warming at night and cooler during the day)

Why are the nights warmer and days cooler?

Plant responses to heat stress, as the temperature increases, plants face heat damage so they must adapte

Transpiration: loss of water by opening stomata

Stomata: pores which CO2 enters and water and O2 leaves

Increased cloudiness from temperature increases

Day effects: clouds block incoming solar radiation (cooling day)

Night effects: clouds block heat loss, warming surface

Patterns of warming are favorable for Chytrid fungal growth

Choanoflagellates

closest living relative of animals

Gastrulation

movements that result in an in-folding of embryo to form a pouch that will eventually form the gut

Blastopore

initial opening formed by the in-folding of cells

Protostome

Blastopore becomes mouth

Deuterostome

Blastopore becomes the anus

Porifera

Asymmetrical

N/A (blastopore)

N/A (germ layers)

No tissues

No Edysis

Collar cells

Cnidaria

Radial

N/A Blastopore

Diplo

True tissues

No edysis

cnidoytes

Platyhelminthes

Bilateral

Protostome

Triplo

True tissues

No Edysis

Diffusion

Ex: flatworms

Mollusca

Bilateral

Protostome

Triplo

True tissues

No edysis

mantel (shells)

Ex: cone snail

Nematoda

Bilateral

Protostome

Triplo

True tissues

Yes edysis

Roundworm, parasites

Arthropoda

Bilateral

Protostome

Triplo

True Tissues

Yes edysis

Ex: cicadas

Joint appendages

Echinodermata

Bilateral

Deutero

Triplo True tissues

No edysis

Vascular water system and tube feet

Ex: Star fish

Chordata

Bilateral

Deutero

Triplo

true tissues

No edysis

dorsal hollow nerve cord

Ex: reptiles

change in populations

N/t = B-D

N/t =

B-D = bN-dN = rN

Carrying Capacity (k)

maximum population size that an environment can sustain because of limited resources, logistic growth model

Survivor curves: Type 1

low birth rate or few offspring survive at a time with high parental care (ex: elephants)

Survivor curves: Type 2

relatively steady chance of death throughout entire life (ex: ground squirrels)

Survivor curves; Type 3

very high mortality rate early in life but low mortality rate for older ages

large groups of offspring without parental care (ex: oak tree or sea turtles)

Interspecific interaction

interaction between species of different species

intraspecific interaction

interaction between members of the same species

Symbioses

when two individual species live in direct intimate contact for prolonged period of time

Parasite, commensal, mutualism

Parasitism

+/- relationship

parasite derives nutrition and energy from its host which is harmed in the process

Commensalism

+/0 relationship

one species benefits and the other is unaffected

VERY DIFFICULT TO FIND TRUE COMMENSAL

mostly blend between commensal and mutualistic

Mutualism

+/+ relationship

which individuals from both species benefit

Non-symbiotic interspecific relationship

species do NOT live in prolonged intimate contact but periodically associate

predation and competition

Predation

+/- relationship

one species eats another (including herbivory)

Competition

-/- relationship

interaction between diffferent species comepting for shared resources (competive exlsusion adn resource partitioning)

Fundamental Niche

full suite of resources potentially used by a species in ABSENCE of competition

Realized Niche

the portion of species fundamental niche actually used in presence of competition

Ecosystem Engineers:

species that directly and dramatically alters their physical environment such that the habitat is maintained or created

Ex: beavers

Savannah elephants

Keystone Species

Species that exert strong control over community structure as function of their niches

Ex: the otter

Wolves

Biosphere Pool

Stored in all living tissues

FAST

(respiration/death/decomposition/photosynthesis)

Carbon fixation

converging inorganic C to organic C in living tissue