Population Growth q

Species

pop of organism that can reproduce & interbreed under natural conditions; 8.7 mill on earth

Endangered Species

Plants & animals that r so rare they may become extinct

Threatened Species

likely 2 b endangered

Factors that can cause extinction

natural event (volcanic eruption), climate change (end of Ice Age), people, pollution, pesticides

What type of protection is offered by the Endangered Species Act of 1973?

Protects critical habitats & restricts trade of threatened & endangered species

Gene pool

combined genetic info 4 specific pop of organisms; each species has common gene pool

Speciation

If the gene pool of 2 pops r sep & cant b shared through reproduction the pops may devel in2 new species

What causes the difference in these groups to heighten over time?

natural selection & adaptation 2 environ

Behavioral isolation (causes speciation)

2 pop incapable of interbreedin bc diff in courtship/ reproduc behavior

Mechanical isolation (causes speciation)

reproduc organs of same 2 groups become so diff cant mate anymore; diff anatomy

Temporal Isolation (causes speciation)

pop mate @ diff times or seasons

Geographic isolation (causes speciation)

pops have been sep by geo barriers (river, mt, road) that prevent reprod

Interspecific competition

competition between species

What is the principle of competitive exclusion and how does it impact species

2 species cant compete 4 same limited resources & both thrive @ the same time

Linear/arithmetic growth

shows pattern incr in constant amount

Exponential/geometric growth

shows pattern incr @ constant rate

Populations increase…

exponentially & can b graphed on J curve

Biotic potential

rate @ which species incr; based on its habitat requirements & reprod rates

Limiting factors

keeps pops from incr 4ever through limits; may cause organisms 2 die or move out of area

Carrying Capacity

when pop eventually stabilizes; # of organisms an environ can support over long period of time

Density dependent

factors have incring effect as pop incr; predators, disease; usually biotic

Density independent

factors affect all pops regardless of how lrg; temp, storms, flood, drought; usually abiotic

When limiting factors limit the population…

J curve wont continue 2 incr; it levels off @ carryin capacity (s curve)

Populations are made of what?

indvid organisms each w/ specif life span

Natality (used when talking about indivd’s life in terms of pop size)

addition of new individ (birth

Fecundity (used when talking about indivd’s life in terms of pop size)

ability 2 reproduce

Fertility (used when talking about indivd’s life in terms of pop size)

# of offspring reproduced

Morality (used when talking about indivd’s life in terms of pop size)

death rate

Life expectancy (used when talking about indivd’s life in terms of pop size)

predicted level of survival

Survivorship curve shows what?

Probability of survival 4 given group or species; 3 curves b asked on natality & morality of individs

Type 1 survivorship curve

low fertility, high parental care, high morality in old age; elephant & humans

Type 2 survivorship curve

consistent morality through lifetime; birds, mice, & reptiles

Type 3 survivorship curve

high fertility, low parental care, high morality early in life; fish & frogs

K Strategists

live in stable environ, reprod slow/fewer kids, strong/ protected, long life expect, usually lrg, type 1 & 2, high energy & parental care

R Strategists

live in unstable environ, reprod rapidly/ensure kids, weak/subj 2 predation, short life expect, small, type 3, low energy & parent care

Population pyramid or age structure diagram shows a snapshot of what?

current pop