BIOL Flashcards
hypothesis
a statement about nature that can be tested by experiments or by new observations
controlled experiment
researcher sets up several groups to be tested, keeping the conditions and set up as similar as possible from one group to the next
variable
the feature of an experiment that is changed by the experimenter from one treatment to the next
test group
the experimenter group that is exposed to the variable in an experiment
control group
the group that is NOT exposed to the variable
scientific method
using observations to generate a hypothesis and then making predictions based on that hypothesis
scientific inquiry
a deliberate, systematic, careful, and unbiased way of learning about the natural world around us
theory
a general explanation of a natural phenomenon supported by many experiments and observations
1st step to research
observations, prior knowledge, article reviews
2nd step
creating a hypothesis and predictions
research hypothesis Ha-
a plausible and testable general explanation for a phenomena
null hypothesis
Ho- no change
predictions
specific outcomes for the particular experiment/ observations designed to the Ha
3rd step
design a study (experimental, observational, meta-analysis, model)
location, species, treatments, control, replicates, variables
4th step part 1
collecting data
4th step part 2
quantifying the data
4th step part 3
statistical analysis
4th step part 4
draw ideas from the analysis
5th step
drawing an evidence based conclusion from the data
final step
share/communicate findings
evolution
changes in the genetic makeup of populations overtime, sometime resulting in adaptation to the environment and the origin of new species
variation categories:
environmental: due to the differences in the environment
genetic: differences in genotype among individuals in a population
what do experiments do?
helps in laboratory evolution understand how life works and they have an immensely important practical side
fossils provide….
strong complementary insights into evolutionary history
3 things that fossils do:
- fossils enable us to calibrate phylogenies in terms of time
- provide our only record of distinct species
- they place evolutionary events within the context of Earth’s dynamic environment history
what are fossils?
remains of once-living organisms preserved through time in sedimentary rock
fossils give us..
provide us direct documentation of ancient life
fossilization requires….
burial (accumulation of sediments from sand or mud on soil harden in sedimentary rocks)
What properties will determine the probability that an ancient species will be part of the fossil record?
properties of organisms and environment
trace fossils
tracks and trails left by animal as it moves or burrows into sediments
molecular fossils
sterols, bacterial lipids, some pigment molecules, which are relatively resistant to decomposition
what did darwin and wallace hypothesize?
that species evolve due to the changes in population from one generation to the next (concept of shared ancestry)
darwin observed:
diversity of life, similar/differences between species, similar/differences between habitats
artificial selection:
humans decide who survive and reproduce and who doesnt
key impacts of natural selection:
concept of shared ancestry between species
focus on populations changing
provides mechanisms by which change occurs
can apply theory to make and test scientific predictions
adaptations:
anatomical, physiological, or behavior tratits that are hereditary, increase survival and reproduction, is functional, increases fitness and the population has a variation.
analogous traits
similar traits, face similar obstacles
vestigal traits
apendex in humans
conclusions from mendel:
genes are passed down from parent to offspring
alleles segregate- parents passes 1 allele to offspring at random
within a single individual, alleles of a gene occur in pairs
both parents contribute equally to the genotype of their offspring
some alleles are dominant in expression to others
central dogma of biology
explains the flow of genetic information within a biological system
somatic mutations
body tissue nonreproductive cells (cancer) cant be passed down
germ-line mutations
reproductive cells; can be passed down
mutations occurs….
throughout the genome randomly
deleterious
harmful
advantageous
beneficial; improve their carriers chances of survival or reproductions
mutations
sources of genetic variation
allele frequencies give us
information about genetic variation
assumptions of HW E?
- no natural selection
- large population
- no migration
- no mutations
- random mating
- no genetic drift
population in the HW e?
all alleles are equal
proportion recessive phenotype is always ________
q2
p is always proportion of ________ in gene pool
dominant
q is always proportion of ________ in gene pool
recessive
p+q is always equal to _____
1
sum of all genotypes is equal to ______
1
directional selection
one survives better than the other
expected:
AA-0.25
Aa- 0.50
aa-0.25
observed:
AA- 0.35
Aa- 0.45
aa- 0.10
change in AA gets better has has better survival
stabilizing selection (best for natural selection)
decrease in variation in population average phenotype
expected:
AA-0.25
Aa- 0.50
aa-0.25
observed:
AA-0.20
Aa- 0.65
aa- 0.15
Aa hetero has better survival
disruptive selection
acts against the average phenotype; more homo individuals than hetero
expected:
AA-0.25
AB-0.50
BB- 0.25
Observed:
AA-0.35
AB-0.30
BB- 0.35
against the hetero decreases
