Unit 10 - Population Ecology & Species Interactions Flashcards

Question

Urn Shaped Age structure diagram

Answer 1

age structure: - few juveniles - some adults - many seniors *no growth - skewed toward post-reproductive individuals (seniors) ***population is declining in size bc fewer young people who can reproduce - socioeconomic issues can cause fewer people to move into the workforce and move into retirement ex: Italy

Answer 2

more recently, the population is bell so it's stabilizing - in the future, they predict that the population will be urn shaped (decreasing) because old people are surviving but not reproducing

Answer 3

summarizes the survival and reproduction rates of individuals in specific age-groups - life tables built by following a cohort of individuals from birth until death - for sexually reproducing species --- usually only females followed bc they're producing the offspring only ***used to make the survivorship curve

Answer 4

birth rate: # of births/population death rate: # of deaths/population Fecundity: # of offspring/time (per female) - generally fecundity is limited by # of gametes (egg) eggs are more important than sperm generation time: - time period from birth of individuals to birth of their offspring - generation time is related to body size (*the bigger you are, the longer your generation time is) Survivorship: it tracks the change in # of individuals in a cohort (a group of individuals within a population at the same time) over time

Answer 5

proportion of individuals alive at each age - species usually follow one of the three survivorship curves - the differences are based on death rates during different life stages

Answer 6

Late Loss - high survival of offspring - high death later in life - females produce few offspring - high paternal care investment (they care for their offspring a lot) - many large mammals are type 1 (ex: whales and elephants)

Answer 7

Constant Loss (linear line) - death is constant across all ages (the proportion of death is constant) common type 2 species: - some rodents, many invertebrates, lizards, annual plants

Answer 8

Early Loss - low survival of offspring (offspring die a lot) - low death of adults (people who survive early life stages have a high survival rate later in life) - females produce a lot of offspring - not a lot of parental investment in care (the parents don't care for the offspring) common type 3 species: - trees, fish, sea turtles

Answer 9

live fast, die young - they produce lots of offspring - high mortality of offspring ex: flies

Answer 10

slow and steady wins the race - produce less offspring - parental investment - lower mortality of offspring ex: elephants

Answer 11

many organisms fall somewhere in between R and K Strategists because they're extremes - the strategies are on a continuum (many species are somewhere in the middle) ex: trees aren't K or R - they're in between K and R - they have many small offspring - no parental care - but slow growth and late reproduction ex: Turtles - many small offspring - no parental care - slow growth - but late reproduction

Answer 12

adding individuals to or removing individuals from a population changes the population size: additions -- can be births or immigration removals -- losses are death and emigration (leaving the population) over time a population can reach a stable size, fluctuate irregularly, or rise and fall in regular cycles

Answer 13

number of births - number of deaths equation HELP

Answer 14

happens when population growth isn't limited by anything: - resources are abundant (food, habitat, space) - can reproduce as much as physically possible (no limits on population growth) dn/dt = rN r= rate of increase for every individual in the population r is the intrinsic rate of increase: - per capita rate at which a population growing exponentially increases in size at each instant (think calculus) N= number of individuals in population at given time ***the bigger the N value, the faster the population growth (the population growth starts slow and then exponentially grows rapidly)

Answer 15

r is small if: - high death rate (individuals that aren't fertile) - low birth rate (sex ratio is skewed more towards males and long generation time) **if low r value = slow growth rates ***large r = faster population growth ex: whales have long generation time and low birth rates so they have low r values

Answer 16

r can vary among different populations (even within the same species) ***r (rate of increase) and N (population size) both determine speech of a population size increasing but no population can keep growing forever -- eventually there are limits that prevent populations from growing forever

Answer 17

effect on population growth depends on population density higher density causes changes in surviorship and fecundity - births may decrease - deaths my increase Biotic Factors: - resource availability (food, space) - predation - competition - infectious disease spread (covid spread more when the areas were more dense) ***when a population is smaller, more eggs are layed - few eggs layed when the population density is high

Answer 18

***density is not important for effects on population in this (proportional effects) density-independent factors' effect on population size is unpredictable abiotic factors: - weather/climate - disturbances - floods, tornadoes, temperature, soil, pH etc. ex: mosquitos - eggs will hatch and population size will increase - each winter, cold temps kill off all of the mosquitos - the death is proportional no matter how big or small the population is

Answer 19

they work together - social animals can resist dangerous weather conditions by collective behavior (they clump up to stay warm) at bigger population density, the better they're able to resist environmental stress of a density-independent event at low density, they don't have enough people to clump up and keep themselves warm

Answer 20

the population size can crash: - populations can grow to big and then crash - populations living on islands are at risk for catastrophic declines population size can stabalize: - they grow at a good rate and then limits set in so they then stabalize

Answer 21

population growth that is slowed by population limiting factors as the population size increases ***population growth rate will be small when population size is either large or small - at low population levels, if resources are abundant, the population is able to grow exponentially ***growth with constraint

Answer 22

carry capacity (K) = maximum population size that a certain environment can sustain (# of individuals that can survive in an environment) - varies over space and time (changes with resources) (K-N)/K = fraction of N still available for population growth

Answer 23

in exponential growth: - if the curve is below the carrying capacity (K - the line) then the growth rate is low - as the curve gets closer to K, the growth rate increases logistic growth: - growth rate is high when the curve is halway in betweem carrying capacity (halway to carrying capacity) ***both exponential and logistic growth look similar when the population growth is low compared to carrying capacity

Answer 24

the variety of different kinds of organisms that make up a community 2 characteristics of community: - species richness (number of different species in a community) - relative abundance (proportion of each species in a community).

Answer 25

used to calculate the diversity of a community - diversity is based on the richness and relative abundance of species in the community Shannon Diversity Index (H) p = relative abundance of each species H = -(pa(ln pa) + pb(ln pb) +....) pa= relative abundance of species A then it's multiplied by the natural log of the abundance of species A **if you're comparing communities to see which is more diverse, the community with the higher H value is more diverse

Answer 26

it's hard bc: - rarity (sample size) - rare species are hard to locate - ID of species (sometimes species look alike so it's hard to tell if they're the same species or different) - Tiny, hard to find species *you want a big sample size so you can account for all of the species

Answer 27

researchers are using new genetic tools like eDNA (environmental DNA) - they use this to survey and identify the species within a community that aren't easily measured using traditional methods

Answer 28

the feeding relationships between organisms in a community trophic level: a group of organisms that have the same function in the food chain (ex: they both eat primary producers) ***food chain helps us understand energy flow

Answer 29

they're the first level (bottom) of the food chain - they convert light (thru photosynthesis) into chemical energy and organic molecules (biomass) **usually plants or algae

Answer 30

second level of food chain (level right above primary producers) - they're consumers that get their energy from organic matter **they eat primary producers so they're herbivores bc primary producers are plants & algae ex: primary producer is a plant and the primary consumer is an insect that eats the plant

Answer 31

level above primary consumers they eat primary consumers - they're carnivores or omnivores depending on what the primary consumer is ex: a rat (secondary consumer) eating a bug (primary consumer) -- the rat is a carnivore

Answer 32

level above secondary consumers tertiary consumers eat secondary consumers carnivores/omnivores

Answer 33

level above tertiary consumers - usually at the top of the food chain quaternary consumers eat tertiary consumers - either carnvores or omnivores ex: bears (usually top consumer in their forest ecosystem) - a lot of their diet is still plants and berries (primary producers) which makes bears omnivores ***you don't just have to eat from the trophic level directly below you - ex: if you're a quaternary consumer you can eat tertiary, secondary, primary producers and consumers...

Answer 34

they are consumers that eat dead or decaying organic material - many organisms do this ex: sharks eat dead whale carcuses

Answer 35

organisms that break down organic matter and convert it back into inorganic matter - they break down dead organic material so that matter can be available to other consumers - important in ecosystems ex: microbes and fungi

Answer 36

populations of organisms living close enough together to interact with each other individuals of multiple species close together = community *goes population then community, then ecosystem

Answer 37

positive for one organism and negative for the other organism - predation (+/-) -- positive for predator and negative for prey - herbivory (+/-) eating plants/algae

Answer 38

predation is a strong evolutionary force (predation causes evolutionary change) - lots of anti-predator (prey) defenses have evolved - this leads to competitive behavior which leads to evolution - 10 types of defense

Answer 39

run and hide - get away from your predator - very common defense mechanism (fighting off your predator is much less common) ex: a deer running from a tiger

Answer 40

predator will have a hard time handling you or eating you 1. mechanical defense (have spines and thorns) ex: cactus has spikes 2. Chemical defense (toxins) - common defense type - common for plants to do this ex: puffer fish use mechanical defense (have spikes) and chemical defense (contain toxic chemical)

Answer 41

annoy the predator so they don't want to eat you ex: skunk sprays smell that predators don't like (it annoys the predator)

Answer 42

very effective defense mechanism - helps you avoid predation - many animals have bad vision and rely on movement (have to stay still) ex: moth looks like a piece of wood

Answer 43

common in insects - the trait they have isn't very characteristic of them (the faker part) ex: the moth has huge spots on it that look like huge eyes (but those aren't it's eyes) which makes them look very scary batesian mimicry (think Batman): a harmless species mimicks a harmful species (ex: false cobra mimicks the scary neck of a real cobra)

Answer 44

being obvious to your predator and letting them know they don't want to eat you because you will hurt them aposematic coloration: warning coloration (bright colors like bees) - be nasty and posiones and let predators know ex: posion dart frog is bright blue

Answer 45

you want someone else to get eaten so you don't get eaten - you don't have to be faster than your predator to get away, you just need to be faster than someone else

Answer 46

watch out for your predators - this works better in populations that work together as a group - they look out for a predator and then they tell the others if there's a predator (alarm them) - individuals take turns looking out (ex: meerkat)

Answer 47

strength in numbers - know that predators will get some of you but not all of you - want more people (so you have less likely chance of getting eaten) ex: honeybees swarm and suffocate a murder hornet

Answer 48

leave part of your body behind (literally:) autonomy: self-amputation - more common in invertebrates - sever the body part and it regrows ex: gecko severs its tail so it can escape and then it later regrows - some starfish can regrow from one leg only

Answer 49

Coevolution - when the predators develop new ways to attack prey to overcome the prey's defense mechanisms (as the prey develop new defense mechanisms, the predators develop new attack mechanisms and then the prey develop new defense mechanisms and the cycle continues...)

Answer 50

the interaction between individuals of at least 2 different species that involve direct phsyical contact (when two different species at least interact thru physical contact) types of symbiosis: - mutalism - commensalism - parasitism

Answer 51

(+/+) both organisms benefit ex: the cleaner wrasse (fish) goes into the big fish's mouth and picks out all of the paarsites - cleaner wrasse benefits by eating the parasites - the big fish benefits by getting the parasites picked out of its mouth ***the relationship can become so close that it's obligatory obligate symbiosis: when at least one organism in the relationship can't survive without the other falcultative species: the partners don't necessarily need each other to survive or reproduce

Answer 52

(+/0) when one species benefits and the other species is unaffecred - usually not an obligatory relationship (one doesn't need the other to survive or reproduce) ex: a bird sits on the buffalo so it can get a free ride (the benefit) and the buffalo takes the bird but is unaffected (the bird isn't heavy so there's no cost to this) **commensalistic relationships can change overtime if the species is being harmed

Answer 53

(+/-) one species benefits and the other species is harmed parasites: - usually much smaller than their hosts - reproduce faster than hosts - adapted to specific hosts - don't want to kill their hosts (many of them want their host alive so they can keep using them) ex: tounge-feeding louse - eats the tounge of the fish and now the fish can't feed ex: bird - lay their eggs in someone else's nest so that the other bird now has to raise the other bird's eggs that aren't theirs

Answer 54

can happen when resources are scarce (not enough to go around) (-/-) - both species are harmed - competition hurts both species involved ex: lions and tigers compete for food Interspecific competition: competition between 2 or more species - happens when species' niches overlap - every species has a unique niche ex: one branch is too thin for the bird, one is too thick, one is just right

Answer 55

two species that share the same limiting resource can't coexist forever (one species outcompetes the other, leading the exclusion of the other species) ex: when the bacteria types are grown separately, they both have logistic growth - when they grow together, they start growing well, but eventually one bacteria species outcompetes the other and grows much more (the other starts declining in growth)

Answer 56

Fundamental Niche: the range of environmental conditions that a species can theoretically tolerate Realized Niche: the portion of the fundamental niche which takes into account limiting factors (where a species is actually found) **interspecific competition makes the realized niche smaller than the fundamental niche

Answer 57

resource partitioning: the division of limited resources by species to avoid competition in the ecological niche (when species divide limited resources to avoid competition for a niche) ex: different bird species eating different parts of the tree so they can all have the resource (tree) character displacement: greater differences in a trait when 2 species co-occur than when either one is present alone (when the species share a trait, they adapt it so that they have different versions of the trait -- when they're apart they can have the same trait) ex: birds had the same beak depth but then one species got a big one and the other adapted to have a small beak - they avoid competition by developing phenotypic differences bc they overlap on a trait

Unit 10 - Population Ecology & Species Interactions Flashcards

(81 cards)