BISC 102 Midterm Flashcards
Adaptation
A heritable trait that increases survival and reproduction of an individual in a particular environment compared to individuals without that trait
Categories of Adaptations
- structural - physical features
- behavioural - learned or inherited actions/activities carried out by organism
- Physiological - internal cellular processes
Darwin’s 5 Observations
- for any species, population size would increase exponentially
- populations tend to be stable in size except for seasonal fluctuations
- resources are limited
- members of a population vary extensively in their characteristics
- much of this variation is heritable
Darwin’s 3 inferences
- production of more individuals than the environment can support leads to a struggle for existence among individuals of a population with only a fraction of their offspring surviving
- survival depends in part on inherited traits. Individuals whose inherited traits give them a high probability of surviving and reproducing are likely to leave more offspring than other individuals
- this unequal ability of individuals to survive and reproduce will lead to gradual change in population, with favourable characteristics accumulating for successive generations
When does natural selection occur?
- heritable phenotypic variation in the populations leads to …
- differential reproductive success - unequal ability of individuals to survive and reproduce
Phenotype
organism’s observable characteristics or traits including physical form and structure, developmental properties, biochemical and physiological properties as well as behaviour
biological fitness
ability of an individual to survive to reproductive age, find a mate, and produce live, fertile offspring relative to that ability in other individuals in the population
Artificial selection
humans have modified other species by selecting and breeding individuals with desired traits (cattle, sheep, dogs, flowers)
fossil record
provides evidence of the extinction of species, the origin of new groups, and changes within groups over time
mold
formed when organism decays completely but leaves behind hollow physical impression of itself
cast
forms when resulting minerals and sediment deposit into a mold and hardens over time (leaving 3D physical replica of hard structures of the organism)
permineralized fossils
forms as an organism decomposes slowly, which allows dissolved minerals to gradually infiltrate interior of cells and harden into stone
True form fossils
preserve the entire natural form of the organism
carbon film fossils
are formed from carbon residue of soft bodied organism that has been buried sediment
trace fossils
provide indirect evidence of life
habitat bias
organisms that live where sediment is actively being deposited are more likely to fossilize than are organisms in other habitats
taxonomic/tissue bias
some organisms (those with hard parts) are more likely to decay slowly compared to soft-bodied organisms
temporal bias
more recent fossils are more common than ancient fossils
abundance bias
organisms that are more abundantly widespread and present for a long time leave evidence much more often than do species that are rare, local, or ephemeral
homologous structures
body parts that share a common ancestor, but many not necessarily perform the same function
- develop through divergent evolutions
divergent evolution
a process in which a trait held by a common ancestor evolves into different variations over time
homoplasy/analogous structures
body parts that perform the same function but have different evolutionary history (similar in function but not resulting from common ancestry)
convergent evolution
process in which species that are not closely related to each other independently evolve similar kinds of traits
vestigial structures
reduced or incompletely developed structure that serves no or little functions - used to be functional in ancestral species
comparative embryology
similar embryological development in closely related species
biogeography
describes the distribution of life forms over geographical areas, both in past and present times
internal validity
the extent to which you can be confident that a cause and effect relationship established in a study cannot be explained by other factors
experimental unit
the physical entity to which a treatment is randomly applied and on which an observation is made
sexual selection
a form of non-random mating which occurs when individuals within a population differ in their ability to attract mates
intersexual selection
mating success determined by between sex interactions (looks at mate choice, often female choice)
intrasexual selection
mating success determined by within sex interactions (ex. male male combat)
good genes hypothesis
the traits females choose when selecting a mate are honest indicators of the male’s ability to pass on genes that will increase the survival or reproductive success of her offspring
sexual dimorphism
differences between the male and female sex in some species
sexy-sons hypothesis
states that females ideal mate choice is one whose genes will produce males with the best chance of reproductive success
monogamy
pattern of having one mate at a time - one male and female in exclusive relationship
- parental care normally involves both parents
polygamy
pattern of having more than one mate at a time
polygyny
one male mates with two or more females
- male walruses
polyandry
one female mates with two or more males
- male usually provide most parental care
ex. spotted sandpiper
polygynandry
two or more males mate with two or more females
promiscuity
mating system where there is no pair bonding
behaviour
change in the activity of an organism in response to a stimulus
behavioural ecology
study of behavioural adaptations that evolved in response to ecological selection pressures
fixed action patterns
sequence of behaviours essentially unchangeable and conducted to completion once started
imprinting
results in newborn animals bonding with their parents
spacial learning
entails memorizing the features or layout of an environment (such as maze, tank, or section of forest)
conditioning
requires that an animal form an association between two events (ie lever and food)
cognition
involves complex thought, which is evidenced in behaviours such as tool manufacture and use, language acquisition, and problem solving
habituation
a simple form of learning in which an animal stops responding to a stimulus after a period of repeated exposure
ecology
scientific study of interactions between organisms and the environment
population
comprises all organisms of given species in defined area (least inclusive)
community
group of populations of different species in defined area
ecosystem
community of organisms in an area and physical factors that they interact with
biosphere
global ecosystem or sum of all the planet’s ecosystems (most inclusive)
quadrat analysis
use to quantify immobile organisms
mark-release-capture
used to quantify mobile organisms
clumped distribution
most common type of dispersion
- distance between neighbouring individuals in minimized as individuals are clustered in groups
random distribution
least common type
- distance between neighbouring individuals is unpredictable
Uniform distribution
distance between neighbouring individuals is evenly spaced
biotic factors
living components of an ecosystem
abiotic factors
non-living or physical components of an ecosystem
producers (autotrophs)
convert energy from sunlight to make chemical compounds into organic compounds
photoautotrophs
(plants) use energy from sunlight to make organic compounds (like sugars) out of carbon dioxide in photosynthesis (ex. algae, cyanobacteria)
chemoautotrophs
use energy from inorganic compounds to make organic compounds out of carbon dioxide or similar molecules
consumers (heterotrophs)
animals that depend on producers for food
- herbivores
- omnivores
- carnivores
decomposers (heterotrophs)
break down dead material and wastes
survivorship curve
graphic way of representing data in a life table
type 1 survivorship
low death rates during early/middle life. increased death rates among older age groups. usually have small number of offspring and provide lots of parental care
- humans
type 2 survivorship
death rates constant over the organism’s life span. organisms with this type may also have relatively few offspring and provide significant parental care
- birds
type 3 survivorship
high death rates for the young, slower death rates for survivors. usually have lots of offspring at once. don’t provide much care for the offspring
- tree releasing thousands of seeds
- trees, marine invertebrates, most fish
semelparity (big-bang reproduction)
reproduce once and die (such as pacific salmon, bamboo, grain crops)
iteroparity (repeated reproduction)
produce offspring repeatedly (such as humans)
population growth
populations are controlled by resources and resources are not unlimited - population can only reach a size that matches availability of resources in its local environment
exponential growth
population’s growth rate increases over time, in proportion to size of population (bacteria growing in lab)
logistic growth
is continuous population growth in an environment where resources are limited
- density dependent growth
r-selected species
has high rates of fertility, low levels of parental investment in the young, high rates of mortality before the individuals reach sexual maturity (evolution favours productivity)
k-selected species
low rates of fertility, high levels of parental investment, low rates of mortality as individuals sexually mature (evolution favours efficiency)
interspecific interactions
relationships between species in a community
competition
(-/- interactions) when a species compete for a resource in short supply
predation
(+/- interaction) refers to interaction where one species kills and eats the other
cryptic colouration
camouflage - makes prey difficult to spot since the blend with surroundings
aposematic colouration
chemical defence - bright warning colours
batesian mimicry
harmless organism imitates appearance of those that are dangerous in hopes they will be mistaken for them by predators (includes good tasting organisms appearing as bad tasting organisms)
mullerian mimicry
two or more unpalatable or harmful species that have the same predators resemble each other’s closely similar warning systems, such as same pattern of bright colours
aggressive mimicry
used by predators. allows predators to approach and sometimes attract its prey
herbivory
(+/-) herbivores eat parts of a plant or algae
symbiosis
relationship where two or more species live in direct and intimate contact with one another
paratism
(+/-) the parasite derives nourishment from another organism who is harmed in the process
mutualism
(+/+) both species benefit from the interaction
commensalism
(+/0) one species benefits and other is apparently unaffected
trophic structure
the feeding relationships between organisms in a community
genetics
scientific study of heredity and variation
heredity
transmission of traits from one generation to the next
variation
differences in appearance that offspring show from their parents and siblings
genes
are the units fo heredity and are made up of segments of DNA (different versions of specific gene called alleles)
gametes
genes are passed to the next generation through reproductive cells called gametes (sperm and eggs)
locus
what specific locations on a chromosome are called
fertilization
union of gametes
diploid zygote
name for fertilized egg
zygote
produces somatic cells by mitosis
homologous chromosomes
two chromosomes in a pair
- can exist as replicated or unreplicated
- have same size (length)
histones
add compaction and protection to chromosomes
condensins
protein rings along length of chromosome to compact chromosome just before cell division
karyotype
ordered display of chromosomes of an individual cell
karyotype
ordered display of chromosomes of an individual cell
autosomes
22 pairs of chromosomes that do not determine sex
centrosomes
organelle that serves as microtubule organizing center
aster
radial array of short microtubules that extends from each centrosome, which connect to proteins on inner surface of cell membrane
kinetochore
capture chromosomes by binding to kinetochore proteins
non-kinetochore
(polar microtubules) do not capture chromosomes
prophase 1
replicated chromosomes condense and spindle microtubules begin to form centrosomes
synapsis
homologous replicated chromosomes loosely pair up, aligned gene by gene
chiasmata regions
where crossing over occurs
crossing over
non-sister chromatids exchange DNA segments to produce chromosomes with a combination of parental alleles
metaphase 1
paired homologs line up at metaphase plate at random
microtubules from one pole are attached to the kinetochore of one replicated chromosomes of each bivalent
microtubules from the other pole are attached to the kinetochore of the other replicated chromosome of each bivalent
anaphase 1
paired homologs separate
one chromosome moves toward each pole guided by the spindle microtubules (kinetochore microtubules shorten while non kinetochore microtubules lengthen
sister chromatids remain attached at the centromere
Telophase 1 and Cytokinesis
homologs (as replicated chromosomes) finish migrating to the poles of the cell (cells are diploid)
cytokinesis occurs and forms two haploid daughter cells
