Topic 10 Reproduction Flashcards
Life history Traits
Traits that an organism has that worked well in the past
traits that have been acquired through the evolution of a species inorder to maximize the reproductive success of that species
maximizing reproductive success involves ___+ ex
trade offs
for ex if energy is put into trying to adapt and exist in the environment, there’s going to be sacrifices somewhere else such as energy available to reproduce
larger seed= (3)
more energy put into it
the seed will likely survive
improve reproductive fitness of a species
Indeterminate growth strategy (3)
growth of the individual continues throughout the lifespan
(ex: ectotherms-reptiles, fish, plants)
larger organism is the oldest
Determinate growth (3)
growth of the organism ceases when adult state is reached (endotherms- birds, mammals)
all of the energy they have at that point is going into maintaining rather then growing
asexual reproduction (3)
produces clones (exact copy)
Prokaryotes replicate their genome and then divide by binary fission
some eukaryotes replicate their genomes and divide by mitosis (Protists, fungi and some plants).
benefit/non benefits of asexual
no energy inputted in finding mates
not producing any sort of genetic variation. Just making clones, and those who grow the fastest will take over the population
sexual reproduction (4)
combined genomes
replicated genomes are halved into gametes (Sperm and egg) and combined with other gametes to produce a zygote
only in eukaryotes
unique genome never seem before, unless your a twin
Disadvantage of sexual reproduction
You have to find a mate, and gestate
the more you reproduce, your growth rate….
decrease
parental investment and offspring connection
More investment means less offsprings
fecundity
ability to produce offsprings
males and reproduction and growth rate relationship
males engaged in less reproduction have larger growth rate (more energy)
passive care
pre birth energy investment (seed development, gestation, of embryo)
organism that have no active care relationship with growth style
tend to follow an indeterminate growth pattern
fledge
ready to fly
parity
how often an individual reproduces
semelparity
individuals of the same species can breed only once in its lifetime
Iteroparity
Individuals of the same species can breed more than once in its lifetime
r- selected (7)
small offspring/ adult size (don’t have a lot of time to grow and put on body mass before they start to make babies as most energy is going into making lots of babies
early sexual maturity
Evolved to reproduce quickly (reproduce quick bc of unstable environment)
semelparous (makes lots of babies and that’s the end of their life)
High fecundity
low juvenile survivorship (lots of babies die very young)
short lifespan
K selected (8)
Large offspring
Late sexual maturity
Iteroparous
low growth rate
Low fecundity (few offspring)
High juvenile survivorship
Long lifespan
Evolved to compete (intraspecific)
Life history table
Summarizes info on age, structures, size, life history reproductive stages and survivorship of a population
The sx, nx table
nx
number of females
lx+ formula
survivorship, fraction of original cohort still alive, indicated by data from females
lx=nx/n0
sx +formula
survival rate from one age to the next
nx+1/nx
mx
fecundity average number of female offspring female produces
R0+ formula
net reproductive rate
average #of female offspring per female in cohort over the cohorts lifespan
r0<1
popultion is decreaing
R0=0
population produced no females, the population is not going to survive until next generation
extinct
r0>1
Population is increasing
survivorship curve has to be
log scaled
Type 1 survivorship (5) + Ex:
K selected species
A lot of survival at the start
High mortality late in life
Applies to animals that are fairly large animals with few young offspring
High parental care which translate to high juvenile survivorship
ex: humans, elephants
Type 2 survivorship (2) + ex:
Constant rate of mortality throughout lifespan
mix of r and k traits
ex: birds, rodents
Type 3 Survivorship (3) + ex
Tons produced Few survive
Mortality rate high at beginning but decrease with age. In a Type III curve, very few organisms survive their younger years. However, the lucky ones that make it through youth are likely to have pretty long lives after that.
Those that make it survive but not a lot of them make it in the first few years
trees, fish
