BIO 1M03 Exam

Definitions

species

an evolutionary independent population or group of populations

gene flow

homogenizes genetic variation among populations, so evolutionary independence starts with a reduction or cessation of gene flow.

biological species concept

assigns individuals to the same species if they “actually or potentially interbreed.”

pre zygotic isolation

occurs when individuals of different species are prevented from mating

post zygotic isolation

ccurs when individuals from different populations do mate, but the hybrid offspring produced either have low fitness/ sterility or do not survive.

morphospecies concept

species are distinguished by differences in size, shape, or other morphological features

phylogenetic species concept

based on reconstructing the evolutionary history of populations

monophyletic groups

contains all descendants of their most recent common ancestor

allopatry

refers to populations or species that live in different places

dispersal

occurs when a population MOVES to a new habitat, colonizes it, and forms a new population. → pre dates time of speciation

vicariance

occurs when a physical barrier SPLITS a widespread population into subgroups that are physically isolated from each other. → same age as speciation

Sympatric Speciation

Speciation that occurs when species are not physically isolated

Autopolyploids

produced by spontaneous genome duplication within a species

Allopolyploids

result from genome duplication in association with hybridization of two different species

Self-fertilization

The type of fertilization more common in plants

Homology

* occurs when traits are similar due to shared ancestry → same place
* a similarity that exists in species that was inherited from an ancestor

Homoplasy

occurs when traits are similar for reasons OTHER than common ancestry → similarities are not due to inheritance from a common ancestor → due to convergence → same form

convergent evolution

occurs when natural selection favours similar solutions to the problems posed by a similar way of life

Maximum Parsimony

assumes that the best explanation or pattern in the one that implies the least amount of change

synapomorphy

a novel trait that a clade of organisms have and that others outside this clade lack

Cryptic Species

Species that are not easily distinguishable from one another

Ecotypes

Evolved independently and repeatedly on the large islands of the Caribbean

Adaptive Radiations

instances of rapid diversification of a lineage accompanies by ecological diversification

background rate of extinction

* refers to the level of extinction during periods when mass extinctions are not occurring
* typically occur when normal environmental change, emerging diseases, or competition reduces certain populations to zero

Mass extinctions

* periods with extreme levels of biodiversity loss
* Results from extraordinary, sudden, and temporary changes in the enviroment; they cause extinction randomly with respect to individuals’ fitness under normal conditions

impact hypothesis

proposes that a meteorite struck Earth 65 mya and caused the extinction of an estimated 60-80% of the multicellular species alive, including dinosaurs.

Environmental Change

increased oxygen concentration in atmosphere increased thickness of the ozone layer, flooding of continental shelves, increased Ca 2+ in oceans

Ecosystem Engineering

animals that change their environment, opening up novel ecological niches

Anthropoids

NWM + OWM and apes, including humans

Hominoids

apes, including humans

Hominins

Human lineage after divergence from chimps + bonobos

Hunting

The practice of pursuing living things for food, recreation, trade, pest control, etc.

Human demography

The study of characteristics of human populations, such as size, growth, density, distribution, and vital statistics.

Organismal Ecology

Ask how adaptations of shape, physiology, and behaviour allow individual organisms to live in a particular habitat

population

a group of individuals of the same species that live in an area

Population Ecology

asks how and why the number of individuals in a population change over time

Community Ecology

refers to species that live and interact with one another in a habitat

Ecosystem Ecology

considers all the organisms in a particular region, along with nonliving or abiotic, components

Global Ecology

Investigates the biosphere the thin zone surrounding the Earth where all life exists

Conservation biology

aims to preserve and restore threatened populations, communities, and ecosystems

Biogeography

The study of how species are distributed geographically

Niche

The suite of conditions a species can tolerate

Climate

the prevailing long-term weather conditions found in an area

Weather

consists of specific short term atmospheric conditions of temperature, precipitation, sunlight and wind

Biomes

regions defined by distinct abiotic characteristics and dominant vegetation

Natural Biome

the type of biome present in a terrestrial region depends mostly on climate → temperature, moisture, sunlight and wind

Stimulation studies

models of weather patterns

Observational studies

long-term monitoring

Historical studies

reconstructing prehistorical trends

Experiments

simulate climate change conditions to record organisms’ responses

The population density

* number of individuals per unit area
* varies throughout the range

Meta-population

a population of populations connected by migration

Life table

shows the probability that an individual will survive and reproduce in any given time interval over the course of its lifetime

Age class

individuals of a specific age

Survivorship

The proportion of offspring that survive, on average, to a particular age

Survivorship curve

a plot of a logarithm of the number of survivors vs. age

biological community

consists of all the populations of interacting species living within a defined area

Commensalism

Occurs when one species benefits but the other is unaffected (+/0)

Competition

Occurs when individuals use the same resources -. resulting in lower fitness for both (-/-)

Consumption

Occurs when one organism eats or absorbs nutrients from another, increase the consumer’s fitness but decreasing the victim’s (+/-)

Mutualism

Occurs when two species interact in a way that confers fitness benefits to both (+/+)

Interspecific competition

occurs when members of different species use the same limiting resources

Intraspecific competition

Competition that is density dependent

Niche

A range of resources and conditions that species deals with

Competitive Exclusion Principle

When superior species uses all the resource space of its competitor, the inferior competitor will disappear

fundamental niche

The total theoretical range of environmental conditions that a species can tolerate

realized niche

Fitness Tradeoffs

The ability to compete for a particular resources is only one aspect of an organism’s niche

Herbivory

the consumption of plant or algal tissues by herbivores

Predation

the killing and consumption of most or all of another individual

Endoparasites

live inside a host’s body and are usually simple and worm-like

Ectoparasites

live outside of a host’s body and typically have adaptation for harvesting fluids from hosts

Parasitoids

Free living as adults but have endoparasitic larvae

→ almost always fatal to hosts

Constitutive or standing defences

defences that are always present

Mimicry

the close resemblance of another species

Müllerian mimicry

when two harmful prey species resemble each other → both benefit

inducible defences

traits produced in response to the presence of a predator

food chain

Multiple consumption interactions → linked together

Food web

How multiple food chains are linked together → summary of consumption interactions in a community

Trophic cascade

when impacts propagate down the food chain

Disturbance

any strong short-lived disruption to a community that changes the distribution of living or nonliving resources

Primary Succession

The gradual colonization of a habitat of bare rock or gravel, usually after an environmental disturbance that removes all soil and previous organisms.

Secondary Succession

Gradual colonization of a habitat after an environmental disturbance that removes some or all previous organisms but leaves he soil intact.

Facilitation

existing species help those that arrive → “building basecamp for new arrivals”

Tolerance

existing species do no affect the arrivals

Inhibition

presence of one species inhibits the success of another

Species Richness

The number of species present in a given community

Species Diversity

A weighted measure that incorporates a species’ relative abundance

The Theory of Island Biogeography

Larger patches of habitat contain more species than smaller patches of habitat

Immigration

Rates should decline as the number of specie son the island increase

Ecosystem

One or more communities in an area + abiotic components

primary producer or autotroph

can synthesize its own food from inorganic sources

gross primary productivity (GPP)

The total energy captured by autotrophs

net primary productivity (NPP)

part of the energy that is produced that is available for consumers (leaves, branches)

Consumers

Eat living organisms

Heterotroph

any organism that cannot synthesize reduced organic compounds from inorganic sources

Primary Consumers

Eat Primary Producers

herbivore; an organism that eats plants, algae or other primary producers

Secondary consumers

* eat primary consumers
* A carnivore; an organism that eats herbivores

Tertiary Consumers

* eat secondary consumers
* A carnivore; eat both primary and secondary consumers

decomposers or detritivores

obtain energy by feeding on the remains of other organisms or waste products