Test 1 Flashcards
Who proposed the theory of inheritance of acquired traits?
Lamarck
Who brought the idea of evolution into the realm of science, earth is older than we think. He developed the concept of the “unity of type”.
Buffon
What 2 people were on the famous voyage on Beagle, developed theory of evolution/natural selection. Observed patterns in organisms on how & why changes took place.
Darwin & Wallace
What 2 people discovered that earth is millions of years old, theory of uniformitarianism.
Hutton & Lyell
What kind of evolution is it when similar traits evolve independently in a species that does NOT share a recent common ancestor?
Convergent evolution
What kind of evolution is it when 2 species evolve in diverse directions?
Divergent evolution
What is the changes in allele frequency in a population over time?
Microevolution
What is the creation of new species with different characteristics in a population over time?
Macroevolution
What does macroevolution do?
Accumulation of small changes in allele frequencies over time to produce enough change where a new species is created.
What is the theory that explains how populations change over time & how life diversifies the origin of species. Does NOT shed light on the beginnings of life including the origins of the first cells.
Theory of evolution
What is an adaptation?
Heritable trait that helps an organism’s survival & reproduction in its present environment.
What is a structure with the same ancestor, different function. Divergent evolution.
Homologous structures
What is a structure with different ancestors, same function. Convergent evolution.
Analogous structures
What are vestigial structures & an example?
Remnants of structures of ancestors that are no longer used. Wings on flightless birds.
What are prezygotic barriers?
before fertilization, blocks reproduction from taking place.
What are the 5 kinds of prezygotic barriers?
Temporal isolation, geographic/habitat isolation, behavioral isolation (mating dances), mechanical isolation (reproductive organs don’t match up), gametic isolation (sperm & egg do not fuse).
What are postzygotic barriers?
Occurs after zygote formation - either organisms do not develop properly or offspring are born sterile.
What is allopatric speciation?
barrier separates population. Ex: river forming a new branch
What is sympatric speciation?
No physical barrier separates population, but microhabitats, behavior, or new alleles (through mutations) may drive separation. Can result in polyploidy.
What is polyploidy?
cell or organism has an extra set or sets of chromosomes
What is a hybrid zone?
Exists when closely related species continue to reproduce. Overtime, zones can change depending upon fitness of hybrids & reproductive barriers.
What are the 3 different patterns of hybrid zones?
Reinforcement, fusion, stabilityW
What is reinforcement in a hybrid zone?
occurs when hybrids are less fit than either purebred species (parents). Species continue to diverge until hybridization can no longer occur.
What is fusion in a hybrid zone?
occurs when reproductive barriers weaken until 2 species become 1
What is stability in a hybrid zone?
fit hybrids continue to be produced
What is Hardy-Weinberg equilibrium & what are the conditions?
baseline model to compare real pop. changes against each other/ Not usually seen in real populations
1. No selection occurs (no characteristics have advantage over other ones)
2. No mutation occurs
3. No migration (no new alleles/genes enter or exit pop.)
4. Large pop. (a chance of death in a pop. would not eliminate a characteristic & subsequent allele)
5. Random mating (no characteristic affords reproductive advantage over another)
What are the 3 mechanisms that will alter gene pool which goes against H-W equilibrium?
Gene flow, genetic drift (founder effect & bottleneck effect) & natural selection
What is gene flow?
if new individuals come into a pop., this can introduce new genes to the gene pool - increasing variation. Flow of alleles in & out of a pop. due to migration of individuals or gametes.
What is genetic drift?
when certain alleles or characteristics are eliminated from a pop. Due to chance!!
What is the founder effect?
subset of the pop. will break away from original with only a portion of original genes & will start a new pop. - descendants of new pop. will be limited to the alleles from portion that broke away
What is bottleneck effect?
Original pop. has dwindled to much smaller pop., resulting pop. does not have variety of alleles that was present in original pop.
What is natural selection?
a selective pressure (like a predator) will eliminate individuals from a pop. based on certain characteristics - does NOT occur by chance.
What are the 3 types of natural selection seen in populations?
Stabilizing, directional, disruptive (diversifying)
What is stabilizing NS?
average of the traits survive best. natural selection favors an average phenotype, selecting against extreme variation.
What is directional NS?
one extreme trait is favored over average, moving the pop. towards one direction & away from prior avg. Selects for phenotypes at one end of the spectrum of existing variation.
What is disruptive (diversifying) NS?
both extreme traits are favored over the avg., the “middle” ground is eliminated.
What is sexual selection?
Certain characteristics are favored in one gender or another, sexual dimorphism or trade-offs can result
What is a trade off?
strong sexual selection can maximize reproductive success at the expense of other traits that are better for individual survival
What are the 6 levels of ecological study?
- Individual
- Population
- Community
- Ecosystem
- Biome
- Biosphere
What are the 5 kinds of species types?
- Foundation
- Keystone
- Endemic
- Pioneer
- Invasive
What are foundation species?
considered base of a community, greatest influence on overall structure. Ex: plants
What are keystone species?
exert influence to maintain biodiversity in an ecosystem. Ex: wolves
What are endemic species?
found only in one location, nowhere else. Typical in isolated islands
What are pioneer species?
1st to colonize an area. Ex: weeds
What are invasive species?
non-native organisms that threaten ecosystem balance
What are the 3 ways that animals regulate temperatures?
hibernation, estivation, migration
What is hibernation?
enables animals to survive cold temperatures. Enter torpor: condition where metabolic rate is slowed
What is estivation?
allows animals to survive hot, dry climates. Enter torpor
What is migration?
regular movement from one place to another.
What is a survivorship curve & what are the 3 kinds?
provides info. about mortality rates at diff. ages. Type 1, type 2, type 3
What is type 1 survivorship curve?
high survival rate at start, maintained through life & decreases at old age. Ex: humans
What is type 2 survivorship curve?
survival rate decreases linearly as age increases, equal chance of dying at any age. Ex: birds
What is type 3 survivorship curve?
survival rate steep decrease at beginning but then those that survive continue into old age. Ex: trees
What are the 2 kinds of growth curves?
- Exponential growth “J-curve”
- Logistical growth “S-curve”
What is exponential growth “J-Curve”?
population increases over time with no limit
What is logistical growth “S-curve”?
population increases until reaches a carrying capacity limit, then levels off.
What is carrying capacity?
associated with growth curves. # of individuals of a species that can be supported by limited resources of a habitat. Ex: amount of food available will limit how many individuals in a population will survive
What are density dependent factors?
factors that depend on pop. size & their impact will increase as pop’s. increase. Ex: competition, predation
What are density independent factors?
factors that affect all pop’s. in a similar way, independent of pop. size. Ex: fires, hurricanes
What are the 3 kinds of symbiotic relationships?
- commensalism
- mutualism
- parasitism
What is commensalism?
one benefits, other not helped nor harmed. Ex: bird benefits from nest in tree & tree is not affected
What is mutialism?
both parties benefit. Bees pollinate flowers
What is parasitism?
one benefits, other harmed. Isopod replaces tongue of fish
What are the 2 kinds of reproductive strategies?
R-selected & K-selected organisms
What are r-selected organisms?
will survive many different environments, many offspring, limited or no care of offspring, short life spans & type 3 curve. Ex. insects
What are k-selected organisms?
survive best in predictable environments, few offspring but increased parental cate, longer life spans, type 1 curve. Ex: large mammals
What is resistance in an ecosystem?
ability to remain at equilibrium despite disturbances
What is resilience in an ecosystem?
speed at which an ecosystem recovers after being disturbed
What is diversity in an ecosystem?
number of species occupying the same habitat
What is Gross primary production (GPP) in a trophic level?
rate at which photosynthetic primary producers incorporate energy from the sun
What is net primary productivity (NPP)?
Energy that remains in the primary producers after accounting for the organisms respiration & heat loss
What are the 4 trophic levels?
- Primary producers (bottom)
- Primary consumers
- Secondary consumers
- Tertiary consumers (top)
What are primary producers in a trophic level?
bottom of the food chain that consists of photosynthetic organisms like plants ex. green algae
What are primary consumers in a trophic level?
organisms that consumer the primary producers. Ex: herbivores
What are secondary consumers in a trophic level?
carnivores that eat primary consumers
What are tertiary consumers in a trophic level?
Carnivores that eat other carnivores. Top of the level, aka apex consumers
What is primary succession?
Newly exposed or newly formed land is colonized by living things. Ex: as lava flows into ocean from volcano, new land is continuously being formed
What is secondary succession?
Part of an ecosystem is disturbed & remnants of the previous community remain. Ex: wildfire
What is biomagnification?
increasing conc. of toxic substances in organisms at each trophic level
