isc bio exam 1 (copy)

mitochondrial eve

last common maternal ancestor of all humans through an unbroken line

y-chromosome adam

most recent common male ancestor of all living humans

LUCA

last universal common ancestor

bacteria’s characteristics

single cell, no nucleus, no membrane-bound organelles, no cytoplasmic structure

archaea’s characteristics

single cell, no nucleus, no membrane-bound organelles, live in extreme habitats but also soils + aquatic environments

eukarya

includes protists/protozoans, plants, fungi, and animals - has nucleated cells w/ cytoplasmic structure & membrane-bound organelles

phylogeny

the study of evolutionary relationships among biological entities, often based on genetic and morphological data

phylogenic trees

evolutionary trees/diagrams that represent a hypothesis about patterns of relationships among species

systematics

the study of evolutionary relationships

ancestral similarity

similarities from most recent common ancestor

derived similarity

similarity that arose more recently, does not come from the most recent common ancestor, and is only shared by a subset of the species

are ancestral similarities or derived similarities considered informational in cladistics?

derived similarities

character states

variations of a character/feauture/trait

ex. character “tail” has 2 states

i. presence of tail

ii. absence of tail

taxon

species or other higher-level groups

polarizing of characters

determining whether a character is ancestral or derived

outgroup method

method that assigns one species or multiple as the outgroup (closely related to the species under study, but not an actual part of it) and compares character states between the two groups

→ when the outgroup exhibits the same character state as the group under study, the state is considered ancestral

→ if not shown by outgroup, it’s considered derived

however: since outgroups also evolve, this method is considered most accurate when the character state is shown in multiple outgroups

what is a clade?

species that share a common ancestor

what does a clade include?

common ancestor + all descendants

synapomorphy

a derived character present in descendants but NOT in common ancestor

plesiomorphy

ancestral states/traits

symplesiomorphies

shared ancestral states/traits (shared among descendants and came from ancestor)

homplasy

character that is similar in different species, but those species don’t have a common ancestor

principle of parsimony

favoring the hypothesis that requires the fewest assumptions

molecular clock

uses the accumulation of DNA or protein mutations over time to estimate when different species diverged from a common ancestor

→ Scientists compare DNA sequences from different organisms, and the number of genetic differences observed is assumed to correspond to the amount of time that has passed since they shared a common ancestor

monophyletic group

includes most recent ancestor + all descendants

paraphyletic group

includes most recent ancestor, but not all descendants

polyphyletic group

characterized by convergent traits, parts of this group have no common ancestor

phylogenetic species concept

defines a species as the smallest group of organisms that share a unique, common ancestor and can be distinguished from other such groups

homologous structures/body parts

structures/body parts that were derived from common ancestor

homoplastic structures/body parts

body parts similar to common ancestor but did not directly come from them

at first, the Earth had a very ____________ environment, likely unable to support ____

inconsistent

life

in Earth’s early atmosphere, ___ levels shifted, changing the temperature

CO2

________ ______ caused the continents to move over time

tectonic plates

life emerged in the _______ time period

Archean

describe the process of weathering

1. water + CO2 in the atmosphere form carbonic acid (H2CO3)

2. carbonic acid interacts with rock to release HCO3^1- and Ca²+

   1. those ions wash into the ocean to form calcium carbonate (CaCO3)

where may early organic molecules have originated from? (2 possibilities)

1. comets and asteroids that slammed onto the Earth

2. Earth’s early environment, which was a reducing environment, meaning it wouldn’t have taken that much energy to make the compounds

what does fixation of an element mean?

making the element biologically accessible

life started off as ______ cells and evolved over time

single

what does increased weathering mean for CO2 concentrations

they decrease

what does low CO2 concentrations lead to?

glaciation, which causes low sea levels

what are the four eukaryotic supergroups

1. excavata, SAR

2. archaeplastida

3. amoebozoa

4. opisthokonta

what is endosymbiosis

two cells living together with one inside the other

what are the 4 key environmental factors?

temperature, water, sunlight, soil

what are the two ways that organisms cope with environmental changes?

1. homeostasis

   1. conforming to the environment

norm of reaction

ability to produce multiple phenotypes from one genotype

what are the 3 important characteristics of population ecology?

1. population range: the area throughout a population occurs

2. the pattern of spacing of individuals within that range

   1. how the population changes in size throughout time

metapopulation

made up of distinct populations that may exchange members

source-sink metapopulations

populations in the better areas (the sources) send out dispersers that support the populations in the poor habitats (the sinks)

demography

the quantitative study of populations

populations grow if there are ____ births than deaths

populations shrink if there are ____ births than deaths

populations stay constant if there is a(n) _____ amount of births and deaths

more

less

equal

generation time

average interval between the birth of an individual and the birth of its offspring

cohort

group of individuals of the same age

fecundity rate

number of offspring produced in a standard time

mortality rate

number of deaths in a standard time

age structure

determined by the number of individuals in different age groups

life table

shows the date of a cohort from birth until death through a table

→ shows # of offspring and # of deaths in each time period

survivorship

the percent of an original population that survives to a given age

type 1: ______ mortality rate as they age

type 2: _______ likely to die at any age

type 3: _____ mortality rate as they age

higher

equally

lower

cost of reproduction

reduction in future reproductive potential due to current reproductive efforts

semelparity

an organism reproduces only once and then dies

iteroparity

an organism reproduces multiple times over many seasons

biotic potential

rate at which a population increases when there are no limits placed on its growth rate

carrying capacity

max population size that can be sustained by a specific environment due to lack of space, water, nutrients, etc.

density-dependent factors

factors that affect population size through time and depend on the size of the population

limitations to population growth regulated by biotic factors such as competition, predation, and disease, which are increased by high population densities

density-independent factors

factors that affect population size through time regardless of the size

limitations to growth of a population regulated by abiotic factors such as severe weather, fires, etc.

is bacteria monophyletic, polyphyletic, or paraphyletic?

monophyletic

is archaea monophyletic, polyphyletic, or paraphyletic?

paraphyletic

is eukarya monophyletic, polyphyletic, or paraphyletic?

monophyletic

Allee effect

population growth rate increases at high densities and decreases at low densities

k-selected organisms/populations

organisms/populations that are adapted to thrive when the population is near its carrying capacity

other characteristics: large body size, few offspring, high parental investment, long lifespans, and late sexual maturity

r-selected organisms/populations

organisms/populations with a short lifespan and high reproduction rates

other characteristics: little to no parental care

population pyramid

a bar graph that displays the number of people in each age category

→ usually males are to the left, and women are to the right

metabolism = biomass to the what power?

¾ (metabolism = biomass³/⁴)