winter mid term Flashcards
what makes earth habitable
-water
-energy/stable sun
-be within habitable zone of a star
-resonable temp (15)
-size and composition
-Stable atmosphere and chemical composition
-Magnetosphere
-moon to stabolize
-ozone layer
-larger outter planets
-stable solar sys
-loco in milky way
what did stanley millers experiment prove?
proved that organic molecules needed for life could be formed from inorganic components.
they were formed under conditions thought to simulate those of early Earth and proves how life started
what is the importance of nebule
it is the death and birth of stars rhat make up life and elements
what did aristotle believe
believed that species were fixed and unchanging.
what did Carolus Linnaeus do?
created the naming system we use for species today (taxonomy)
what did Georges Cuvier do?
studied fossils and realized life had been recored within rocks.
what did James Hutton do?
believed things would change overtime (gradualism)
what influecnced darwin
the conclusions from Charles Lyell.
he thought geological changes would be slow and overtime, and that the earth was very old
when did the major groups of organisms arise?
the cambrian era
what is natural selection
Organisms that are more adapted to their environment are more likely to survive and pass on the genes that aided their success
what were conditions of early earth
hot
thick atmosphere
no oxygen or ozone layer
toxic gases
lots of volcanos and extreme weather
what is the oldest prokaryotic fossil from?
3.5 billion years ago
what are the 3 eons started w oldest
The Archaean (4.6 bya
to 2.5 bya)
The Proterozoic (2.5 bya to ~ 542 mya)
and
The Phanerozoic (542 mya to present day)
what happened in The Archaean eon
-4.6 bya-2.5bya
-first prokaryotic life
-oxygen started
what happened in the Proterozoic eon? when was it?
-first eukaryotic life
-first multicellular eukaryotes
-2.5 bya to ~ 542 mya)
what happened in the Phanerozoic eon? how long ago was it? what are the 3 divisions?
-organisms began life outside of water
-larger forms of life began 500 mya
-explosion of multicellular life of all kinds and has been subdivided into the following three eras – Paleozoic (542 – 251 mya); Mesozoic (251-65.5 mya) and the Cenozoic (65.5-
present day
-542 mya to present day
when and what is the cambrian explosion
abt 542 mya- 488 mya, a sudden increase in animal diversity and showed first similarities to modern animals
when was earth formed? when was the big bang?
e- 4.6 bya
b-13.8 bya
what is the cryogenion period? when was it?
720–635 million years ago in the Neoproterozoic Era, it was really cold, ice age
what is the permian extinction?
251 mya
biggest extinction
96% marine and 70% land species died because of CO2 released by volcanic activity
what happened in the Paleozoic era
all life was aqautic
what happened in Mesozoic era
first mammals and flowering plants, age of dinos
what happened in the Cenozoic era
current, evolution of mammals, birds, insects, and angiosperms 65 mya.
what is the cretaceous extinction?
65.5 mya
end of dinos
180 km meteor hit and ejected materials, blocked sun, added acids, and shut down photosynthesis
what is the tarassic era
251 mya, start of dinos, origin of mammals
what is the snowball earth theory
in the cryogenion period, the earth was super cold and suggests that most life would have been confined to areas near deep ocean vents and hot springs, or to equatorial regions of the ocean that
lacked ice cover.
what are plate techtonics
irreg shaped plates that float on the mantle and move 2 cm a year.
the movement of these is why earths surface looks the way it does
what is the colonalization of land? when was it?
movement of species out of water to land 500 mya
what is the continental drfit
the theory that all of the continents in the world once formed a single giant continent that ultimately split apart around 200 million years ago in a process called continental drift.
first broke apart in mesazoic era
when did our continents take shape
65 mya
what are the layers of earth starting superficial
crust
mantle, hot
outer core, liquid
inner core, hot solid
what is sea floor spreading
happens when two tectonic
plates diverge (pull apart) and
Magma from the mantle
rises to fill the gap, creating a ridge at the bottom of the ocean
explains why ocean is widening
what is subduction
Where two plates come together, the lighter of the two will rise on top of the other while the heavier plate gets pushed down into the hot
mantle, where the rock may melt and form volcanoes
what is the ring of fire?
because of plates often colliding, volcanoes erupt and earthquakes happen frequently.
located in pacific ocean
what is reffered to as “the great dying”
Permian extinction
What is an adaptive radiation?
an event in which a lineage rapidly diversifies
how are fossils dated
Radiometric dating, uses the decay of radioisotopes to determine the age of the sample.
use C14 as it decays over time, and When the animal dies, it stops accumulating carbon and we can look at the amount of C-14 present in the organism
what is a population
group of individuals of the same species that live in the same area and interbreed
what is a gene pool
the total collection of genes in a population at one time. It equals all of the alleles in all
of the individuals within the population
where do new alleles come from?
mutations, a change in DNA sequence
what is the Hardy–Weinberg principle
a principle stating that the genetic variation in a population will remain constant from one generation to the next
what does the HW equation letters mean
p- dom
q- recessive
p+q- 1
p2- WW
pq- Ww
q2-ww
what is the HW equation
p2+2pq+q2=1
What is genetic drift?
rapid shift in allele frequencies in a population. it drifts from what it was on average to something notably diff
what is a bottleneck event
reduction in the number of alleles within the gene pool
what is the founder effect
what happens to genetic variability when a small group of a pop settle on a new island.
bc group is smaller traits are inherited more often than they would in a large group
what is gene flow?
occurs when a population gains or loses alleles when fertile individuals or their gametes move in or out of the pop
what are Three ways Natural Selection can alter populations?
stabilizing, directional or disruptive
what is stabilizing selection?
Functions to reduce variation and maintain a particular trait
what is direct selection?
selective pressure against one of the phenotypic extremes, a mid range of variablility
what is disruptive selection?
Extremes are favoured over intermediate phenotypes.
What is sexual selection
individuals with certain traits are more likely than others to obtain mates.
what is sexual dimorphism?
a difference in appearance between males and females
what is intersexual selection
between two sexes
females may be picky w mates
what is intrasexul selection?
selection within the same sex, males compete w each other
Why can’t natural selection make perfect organisms?
-It has to work with existing alleles.
-Evolution is descent with modification, not a recreation of the entire organism.
-Adaptations are compromises, can be good on land but horrible in water.
- beneficial alleles may be lost from a population
what does the HW equation test
if a population os evolving
What is microevolution?
a change in allele frequency
what is Macroevolution?
major evolutionary change. The evolution of whole taxonomic groups over long periods of time.
what is a species? what 4 ways can you define one?
A species is a group or population whose members have the potential to interbreed in nature and
produce fertile offspring.
Biological, morphological, ecological, phylogenetic
what is speciation?
the population has changed enough that it diverges from its present species and becomes a new species
what is biological species concept
A species is a group or population whose members have the potential to interbreed in nature and
produce fertile offspring
what is Morphological Species Concept
based mainly on physical traits
such as shape, size, appearance etc
Ecological Species Concept?
species is adapted based on their ecological niche (nest) and the role they play in their environment
Phylogenetic Species Concept?
based on evolutionary history,
he smallest group of individuals that share a common ancestor and thus form one branch on the tree of life.
what is reproductively isolated ?
prevents genetic exchange between species
what is a reproductive barrier
prevents organisms from interbreeding
can be prezygotic or postzygotic
what is prezygotic? what are the 5 types?
occur before fertilization takes place.
5 types;
-habitat iso, live in diff habitats and dont see each other
-Temporal isolation, organisms breed at different times
-Behavioural isolation, diff ways of repro
-Mechanical isolation, the reproductive parts don’t fit or align.
-Gametic isolation –not able to fertilize.
what is postzygotic? what are the 3 types?
occurs after fertilization takes place
-Reduced hybrid viability, offspring wont survive
-Reduced hybrid fertility, offspring cant breed (sterile)
-Hybrid breakdown, can mate but their offspring wont survive
allopatric speciation
species are geographically
separated from one another and gene flow can no longer occur between them
sympatric speciation
a new species arises within the same geographical area as its parent species and they both continue to live
what is Polyploidy
the heritable condition of possessing more than two complete sets of chromosomes. most common in plants, creates triploid species
what is punctuated equilibrium?
long periods with little change to species, punctuated w rapid change
What is phylogeny?
the origin of diff groups of animals
what is convergent evolution?
species from different evolutionary branches may come to resemble one another if they live in similar environment and natural selection has favoured similar adaptations.
what is Analogy?
the similarity between two species due to convergent evolution, rather than descent from a common ancestor.
what is a homologous character?
characters in different organisms that are similar because they were inherited from a common ancestor
what is a Analogous character?
performing a similar function but having a different evolutionary origin, such as the wings of insects and birds
How do we use systematics to classify life?
classifies organisms and determines their evolutionary
relationships.
Cladistics is the most common way, Common ancestry is used to group organisms into clades.
what is an Outgroup and ingroup?
o- taxon that is not apart of what youre studying
i- the group of taxa whose evolutionary relationships are being determined
How can we study the evolutionary history of a species?
fossils, homologies, molecular systematics
what is molecular systematic?
uses DNA or other molecules to determine relatedness
What is a Virus?
mirco organism that injects genetic material and infects a host cell.
why arent viruses considered living
DO NOT
-metabolize
-reproduce independently
-respond to stimulus
-complex grow
-cell composition
What is the lytic cycle?
when a virus is exiting a cell it causes it to rupture (lysis)
what is the lysogenic cycle?
when a virus injects DNA directly to host so the cell continues to divide w virus DNA in it
what are shapes of viruses?
-rod shaped,
-icosahedral shaped (20 sided),
-round and covered in spikes,
-icosahedral head and a rod
shaped “body” with tail fibers. (mini spider)
how do viruses enter a cell
-by injecting genetic info to host cell
- by attaching to a cells receptor and entering thru endocytosis
how do viruses exit a cell
-lytic cycle, cause cell to rupture
-lysogenic cylce, cause cell to reproduce w virus in each one
What is an emerging virus and what contributes to their creation?
appears suddenly and is new to science. (HIV or COVID).
-mutation
-increased contact w species
-spread from isolated populations
What is a viroid?
naked circular RNA molecules that infect plants. There are no known viroids that infect animals.
what is a retrovirus
contain an enzyme called reverse transcriptase. This transcribes an RNA into DNA, which is the opposite of normal transcription
what is a prion?
has no genome at all and is simply a misfolded form of a protein normally present in brain cells
infect only animals
alzeimers and parkinsons
Can you catch a cold from being cold?
no, being cold as a human actually increases immune func
why are emerging viruses more of a threat
spread quickly and we know nothing abt it
whats the cause for common colds
rhinoviruses
Can antibiotics help against viruses?
no bc theyre surrounded by a protein coat and dont have cell walls to be attacked by anitbiotics
what types/shapes of bacteria is there
cocci- round
bacilli- rod
spirochaetes- spiral
Strep- form chains
Staph- form clumps
what is the smallest form of life
bacteria
what is a gram stain test
tests what bacteria can hold a stain.
they can be gram + bacteria, stain purple
or gram - bacteria, stained pink
what is photoautotrophic bacteria
they get energy from the sun to make organic molecules out of CO2
what is Photoheterotrophic bacteria
they get energy from sunlight but carbon from organic sources
what are Chemoautotroph bacteria
harvest energy from inorganic
chemicals and use carbon from CO2 to make organic molecules
what are Chemoheterotroph bacteria
acquiring both energy and
carbon from organic molecules,
most common
why are bacteria good for us?
important to our microbiome.
- develops immune sys
Why shouldn’t we use antibacterial soaps?
bc they contain Triclosan which interacts with an enzyme that
maintains the bacterial cell wall and bacteria can become resistant to
what is dysbiosis
a microbial imbalance on or inside a body, caused by poor diet or use of antibiotics
what are Archaea
closer to eukaryotes than pros,
extremophiles,
outer lipid layer so they can survive extremes
what is an extremophile?
live in extreme environments that would normally kill other organisms
symbiosis
a physically close association between organisms of two or more species
halophiles
live in salty environment
thermophiles
live in hot environments
Endosymbiosis
a symbiotic relationship between 2 organisms where they both benefit and one lives inside the other.
explains how prokaryotes merged and made eukaryotes
mutualism
a relationship where organisms living in symbiosis both benefit from the relationship
What is a protist?
unicellular eukaryotic organisms.
-use all forms of repro
-can be photoautophoic, hetero, or both (mixotrophic)
-NOT a plant, animal, or fungus
What are fungi?
- heterotrophs that absorb food through their cells
- eukaryotes
- secrete enzymes that breakdown macromolecules and absorb the nutrient
what are Hyphae
each of the branching filaments that make up the mycelium of a fungus, allows spores to spread.
consist of chains of cells
separated by cross-walls with
pores large enough to allow
things to pass
what is Mycelium?
A mass of branching hyphae
What kind of cell wall do fungi have?
made of chitin which is strong and flexible and contains a N-containing
polysaccharide
Are fungi closer to plants or animals?
animals
are adult fungi haploid or dipoloid? what abt zygote?
adult- haploid
zygote- diploid
imperfect fungi
asexual repro is only means of spore formation
molds and yeasts
what is the heterokayotic phase in fungi
where hyphae of two parents
fuse cytoplasms, but may remain haploid
what are Mycorrhiza?
fungus and plants come together and both benefit from the relationship.
fungi get sugar from the plant and the plant gets an increased surface area for water uptake and gets supplied w nutrients
what are the uses of plants
food
clothes
medicine
building material
what is asprin made from? what % of medicine is from plants?
- willow bark
-25%
what are Angiosperms?
flowering plants
what is the plant life cycle?
gametohpyte plant (n) - produces sperm and egg by mitosis - fertilization - zygote - sporophyte plant (2n) - meiosis - produces spores
where did plants start
in water w algae w flagellated sperm
Bryophytes
mosses, liverworts,
hornworts – dominant
gametophyte, very small
sporophyte, no vascular tissue,
spores not seeds, flagellated sperm
Pteridophytes
ferns, Dominant sporophyte, reduced gametophyte, leaves,
vascular tissue, spores not seeds
Gymnosperms
mostly evergreen
trees and Angiosperms, dominant sporophyte, vascular tissues, pollen, seeds.
what are 7 Adaptations for living on the land for plants?
-vascular tissue, structural support
-surfaces covered in waxy cuticle to prevent water loss
-stomata holes that allow for gas exchange
-specialized roots, stems and leaves
-Xylem and Phloem
-pollen and seeds
-seed disposal, wind, water, animsl
what is Xylem? what is Phloem?
x-consists of dead cells that form pipes to convey water and minerals up from the roots
p- living cells that distribute sugars
throughout the plant
earliest land plants are…
bryophytes
whats the diff between spruce a fir trees
s- leaves come off of the branch singly, they are “squarish” in cross section and can be easily rolled between the fingers
f-leaves come off of the branch singly; they are soft and flat – cannot be rolled between the fingers
whats the diff between Pine and Tamarack trees
p-come off of the branch in clusters of 2-8, They are “roundish” in cross
section and can be rolled between the fingers. They are often pointy.
t- needles come off the branch in
clusters of 15-25, they are soft, and turn yellow in the fall before falling off tree
How do pollen and seeds “get around”
wind, water, or animals
What is an animal
multicellular eukaryotes and are heterotrophic
Basic animal life-cycle;
- m and f make gametes
-zygote forms
-zygote div by mitosis
-Blastula stage – a hollow ball of cells
-Gastrula stage – the hollow ball of cells folds in on itself
-dev into adult or larva - organisms that have a larval stage, they must pass through metamorphosis
how do we organize animals?
by types of symmetry, embryonic tissue layers, absence/presence and type of body cavity (coelom)
what is radial and bilateral symmetry?
r-A body plan that radiates from a
centre
b- L and R side mirror each other
what are the 3 embryonic tissues
endoderm(inner) give rise to internal gut organs, ectoderm(outter) give rise to nervous sys, or mesoderm(mid) give rise to musc tissues and CT
what is a coelom?
Animals with all three embryonic tissues may also have a body cavity called a coelom – a fluid filled
space between the digestive tract and outer body wall
what are Sponges
primitive, sessile, no true tissues, no real symmetry, no coelom.
Water flows into small pores throughout the sponge body and is
directed towards the excurrent pore, called an osculum.
consume food via phagocytosis and produce food vacuoles
what are primitive animals?
ones that dont change much over time, look similar to ancestors
what are Cnidarians?
radial symmetry,
two tissue layers,
animals like jellyfish,
all have stinging tenticles,
carnivores,
incomplete digestive system
what are characteristics of Flatworms?
Phylum Platyhelminthes
bilateral symmetry
three tissue layers, but no coelomic cavity
acoelomates
live in marine enviros
what are Rotifers? how do they feed?
aquatic
multicellular
use cilia for food
bilaterally symmetrical,
have three tissue layers,
a complete digestive tract,
a pseudocoelom
has organs
use parthenogenesis to repro
whats is parthenogenesis?
a process where an organism produces diploid eggs that do not need to be fertilized and will turn into females, rotifer use this
what are Nematodes, round worms?
bilaterally symmetrical,
have 3 tissue layers and a pseudocoelom
complete dig tract
decomposers
humans can host them
what are Tardigrades? what can they withstand in tun state?
bilateral symmetry, a complete digestive system, 3-tissue layers, mostly a pseudocoelom
plant-eating,
in tun state, theyre lifeless and can withstand extreme temps.
what is cryptobiosis (tun state)?
tardigrade/water bears, they pull in their head and legs, lose most of their water and go into a state of suspended animation. In this “tun” state they are lifeless and can withstand 0 water, super high temperatures, super low
temperatures, and radiation levels
what are Molluscas? what are their body planes?
Includes slugs, snails, oysters, clams, octopuses and squid (soft bodies)
3 germ layers and a true coelom,
complete digestive tract and circulatory system
body plane- foot for movement, visceral mass which contains internal organs, a mantle which covers viseral mass and makes shell, and a radula to scrape up food
what are the 3 types of molluscas
gastropods (snails),
bivalves (clams, oysters, mussels and scallops), and
cephalopods (squid and octopods)
How intelligent is an octopus? How long do they live?
-go thru small spaces
-find their way back to ocean
-can open jars from inside and out
-can build
-take things apart
-camo
-use tools
live for 2 yrs or less
what are Annelids
-segmented bodies
-bilaterally sym
-have 3 tissue layers and a true coelom
- 3 groups earthworms,
polychaetes, and leeches
What is a hydrostatic skeleton?
a skeleton formed by a fluid-filled compartment within the body, called the coelom
Arthropoda, state 7 thinngs
jointed legs
most numerus animals
includes insects, arachnids, crustaceans (crabs, lobsters), millipedes, centipedes,
Have an exoskeleton of chitin,
segmented bodies
bilaterally symmetrical with 3 tissue layers and a true coelom
what are some adaptations for insects
- waterproof
- camo
Which animal kills the most people?
Mosquitoes bc they spread infections
Basic mosquito life cycle. do males bite?
4 main stages – egg, larva, pupa, adult
no
How do mosquitos find their victims?
smell
Basic dragonfly life cycle.
egg, larva (nymph) which lives in water for 1-3 yrs, shed exoskeleton and become an adult and only survive for only few weeks to months
Benefit of having a larval stage that lives in a different environment (niche) from the adult stage.
allows them to avoid competition, gather food,
what are Echinoderms?
sea stars
radially symmetrical
what is a protostome vs. a deuterostome?
In protostomes, the first opening in the embryo becomes the mouth. In deuterostomes, the first opening in the embryo becomes the anus
What are the 4 main characteristics that all chordates have?
a notochord, a dorsal hollow nerve cord, pharyngeal slits, and a post-anal tail
what are The first chordates do not have vertebrae ?
tunicates, lancelets, and hagfishes
What is a vertebrate?
Any animal with a backbone
as a group fish are…
aquatic
cold blooded
lay eggs, many eggs
little parental support
what is the amniotic egg?
allowed vertebraes to lay eggs outside of water
what are lampreys?
oldest living lineage of vertebrates, lay eggs in water
chondrichthyans?
jawed vertebrae with gills and live under water.
sharks and rays
vertebrae made from cartillage
what are amphibians?
vertebrae in water
repro in water but live on land
cold blooded
larval in aquatic state
tetrapods (animals with two pairs of limbs)
first to colonize land
Reptiles
100% of their life cycle on land
covered in scales w keratin
cold blooded
has specialized amniotic egg
birds
warm blooded
lay eggs
have feathers
fewer offspring and parental support
what are the first mammals to arise
monotremes, platypus and echidnas
theyre egg layers
have fur and secrete milk
what are Eutherians?
true mammals
placental mammals and the young fully develop within the confines of
the uterus, with the young born fully developed
