ecology lecture 4

Question 1

natural selection

Answer 1

the differential success (in terms of reproduction and survival) in organisms with different heritable traits resulting from the interaction of organisms with their environment; OR, the differential survival and reproduction of organisms such that those organisms best suited (or adapted) to their environment become more abundant. *sometimes there are conflicitng natural selection pressures. *end result of natural selection

Question 2

natural selection works on what?

Answer 2

populations

Question 3

adaptation

Answer 3

a heritable trait (which can be a physiological, morphological, or behavioral trait) that improves an organism’s ability to survive and/or reproduce under prevailing environmental conditions. Not all traits that animal/plant has are adaptions.

Question 4

adapation can be a response to what?

Answer 4

abiotic and biotic factors

Question 5

adaptation can help an organism to ?

Answer 5

survive and reproduce

Question 6

heritable trait

Answer 6

any characteristic of an organism that is genetically controlled

Question 7

chromosomes

Answer 7

the full set of DNA for an organism; the chromosomes are in every cell; the DNA codes for all proteins (and thus all heritable traits) that an organism has

Question 8

evolution

Answer 8

change in the genetic makeup of a population over time resulting from natural selection. Evolution does not create progress or perfection. All evolution dependent upon genetic change.

Question 9

chromosomes(2)

Answer 9

grouping of genes in plants/animals cells carry certain types of genetic information

Question 10

Directional Selection

Answer 10

selection in one direction; where traits on one extreme are favored or traits at the other exterme are elimated [SHIFT toward other extreme. Giraffe short neck not reach leaves–so shift to favor long necks]

Question 11

Diversifying/Disruptive selection

Answer 11

intermediate forms of a trait are selected against and the extreme forms of the trait are favored [selection pressure act against folks in middle of trait distribution. fish size, large size eats medium sized, small sneak around] ]

Question 12

Stablizing selection

Answer 12

intermediate forms of a trait are favored and the extremes forms of the trait elminated [ selective pressures select against 2 extremes of a trait. color snails shells: white brown dark brown, beach is brown – so white and dark brown vanish

Question 13

type/forms of natural selection?

Answer 13

graphical form: standard distribution of trait across population X=quantification trait (saying height) and Y=# individuals with a trait. Selection pressures act differently: stablizing selection, diversifying/disruptive selection, and directional.

Question 14

gene*

Answer 14

each of these distinct pieces of DNA have instructions/codes called genetic information for making certain proteins.

Question 15

genotype&phenotype

Answer 15

if a trait is produced from a gene or genes with varying alleles, several possiblites traits exists. The combination of alleles that make a particualr trait is genotype while trait expressed/observale characteristics is phenotype.

Question 16

gene pool*

Answer 16

entire collection of genes within a given population. [Brandon: all alleles present in Population]. [individs in population will have only 1 pair of alleles for particular trait. Yet gene pool may contain dozens or even hundreds of alleles for this trait. Evolution=change in allele frequency over time[CLEP]

Question 17

allele*

Answer 17

chromsomes carry genetic info. Most orgs have corresponding pairs of chromos that carry genes for same traits. Pairs=homologous chromosoms. Genes that produce given trait exist at same position(or locus) on homologous chromos. Each gene may have different forms=alleles. yellow and green seeds arrise from different alleles of same gene. CLEP

Question 18

genome

Answer 18

of a species is made up of the entire sequence of DNA letters or base pairs that combine to spell out the chromosome in typical members.

Question 19

meiosis (sexual reproduction)*

Answer 19

produces gamet cells with 1/2 genetic info of parents (paired chromosomes are separted & sorted independently. So each gamete may rx one of any # of combinations of each parents chromsomes. 2)process producing 4 haploid 9single chromosome gamete cells) from one parent diploid (double chromsome) cell

Question 20

differential reproduction*

Answer 20

phenomemon in which individs w/ adaptive genetic traits produce more living offspring than do indivds w/o such traits

Question 21

speciation

Answer 21

formation of 2 species from one species because of divergent natural selection in response to changes in environmental conditions; usually takes thousands of years

Question 22

genetic diversity

Answer 22

variablity in genetic makeup amon individuals within a single species

Question 23

genetic drift*

Answer 23

allele’s frequency changes in population due to random chance. In each generation, some individuals may, just by chance, leave behind a few more descendents (and genes, of course!) than other individuals. The genes of the next generation will be the genes of the lucky individuals, not necessarily the healthier or better individuals.

Question 24

gene flow*

Answer 24

also called gene migration, is the transfer of genes between different populations through migration. Migration into or out of a population may be responsible for a marked change in allele frequencies (the proportion of members carrying a particular variant of a gene).

Question 25

how do new species evolve

Answer 25

barrier or distant migration (geogrpahic isolation) leads to prevention of flow of genes between 2 or more populatios of species (reproduction isolation).

Question 26

geographic isolation

Answer 26

phase 1 of how new secies evolve: species become physically isolated-migrate in search food. Physical barrier (mountain rnage, stream, road, volcanic eruption, winds/water carry distant area)

Question 27

reproduction isolation

Answer 27

mutation and change by natural selection operate independently in the gen pools of geographically isolated populations. if process continues long enough, members of geographically & reproductively isolated populations of sexually reproducing species may become so different in genetic makeup that they cannot produce live, fertile offspring if they are rejoined and attempt to interbreed. Then one species become two and speciation has occurred.

Question 28

speciation

Answer 28

formation of 2 species from one species because of divergent natural selection in response to change in env conditions (1000 yrs)

Question 29

agent of selection

Answer 29

abiotic and biotic (predations, competition) factors which apply the selective forces causing differential survival and reproduction OR the element which drives evolution by natural selection

Question 30

coevolution

Answer 30

evolution brought about by two or more species interaction (predation, competition, mutalism, parasitism, etc) and exert selective pressures on each other that can lead each species to undergo adaptions – predators cause prety to evolve adaptions AND prey cause predators to evolve adaptions. co-evolution is often compared to an evolutionary form of an arms race. As one species evolves, the other species it interacts with must also evolve or they may go extinct. (prey though catch)

Question 31

poplulation

Answer 31

a group of individuals of the same species living in a particular place

Question 32

mutations

Answer 32

a change in the DNA; since the DNA codes for all of the traits of an organism, a change in the DNA (or the instructions) can sometimes (but not always) cause a change in the traits of the organism (adding new variations to a population)
They are random. omatic mutations occur in non-reproductive cells and won’t be passed onto offspring.

Question 33

Antibiotics or antibacterials

Answer 33

are a type of antimicrobial used in the treatment and prevention of bacterial infection.

Question 34

Antibiotic resistance

Answer 34

is when antibiotics no longer work against bacteria.

Question 35

meosis

Answer 35

special type of cell division. Process required produce egg and sperm cells for sexual reproduction. Unlike mitosis, the way normal body cells divide, meiosis results in cells that only have half the usual number of chromosomes, one from each pair. For that reason, meiosis is often called reduction division. In the long run, meiosis increases genetic variation. Humans total of 46 chromosomes, present in 2 copies from each parent (23 x 2=46) = diploid organisms.

Question 36

sexual reproduction

Answer 36

Sexual reproduction takes place when a sperm fertilizes an egg. The eggs and sperm are special cells called gametes, or sex cells. Gametes are haploid; they have only half the number of chromosomes as a normal body cell (called a somatic cell). humans = 23 chromosomes

Question 37

selected for and selected agains

Answer 37

AGAINST selective pressures select against a particular trait or FOR a particular trait

Question 38

genetic variations

Answer 38

describes naturally occurring genetic differences among individuals of the same species. This variation permits flexibility and survival of a population in the face of changing environmental circumstances.

Question 39

Sexiest changes when ____ changes

Answer 39

JAE: Sexiest changes when selection changes (Dynamic Process) [ in other words when selective forces change, those sexy traits, those traits that are best suited for the particular environment circumstances change ]

Question 40

reproduction (seletion) of the sexiest traits NOT ___ ___ __ ___

Answer 40

not survival of the fittest