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