Chapter 1: Biodiveristy Flashcards
what species are included in biodiversity?
all eukaryotic species
how many eukaryotic species have been named and described?
2.1 million
number of animals
1.5 million
what group is the animal kingdom dominated by?
insects, especially beetles
percentage of vertebrate species in all eukaryotes
<4%
what animal makes up almost half of all describes vertebrate species?
fishes
terrestrial vertebrates comprised _____ of eukaryotic species on earth
~2%
but how many species are there really?
- hard to find species tucked away in remote places
- less attention for less charismatic species
- morphologically similar but with DNA shows differences
- crazy worlds of species within each individual
what approach helps improve our estimates of biodiversity?
molecular DNA
wildlife =
vertebrate species
wildlife definition
free-living, undomesticated vertebrate species
examples of wildlife
- mammals
- birds
- reptiles
- amphibians
- fishes
wildlife in biodiversity
the very small (<4%) subset of biodiversity
why care about biodiversity/wildlife?
- ecosystem services
- storehouse of raw materials & services
- emotional, cultural, educational, spiritual, inspirational, and soul-filling values
what contributes to a species influence on its community & ecosystem?
- local density
- geographic range
- per capita impact of each member of the species
modern rate of population change 1960-2022
- human population growth reached its peak of 2.2% increase per year in the 1960s
- then began to decline, but stayed positive
why did population begin to decline but stay positive?
vital rates
population growth is all about the vital rates
- increases from 1800 to 1970 largely driven by increased survival
- since ~1970s survival has continued to increase only a little bit while fertility has sharply decreases
- this has driven a decline in population growth rate
survival cant go much higher, but…
- reproduction is decreasing (esp in urbanized worlds)
- births likely match deaths in a few decades, but growth will continue
when will our population trajectory flatten?
by the end of this century
why does growth continue in populations?
population momentum
reasons why reproduction is decreasing
- less push for larger families needed for chores, hedge against infant mortality
- women more employable, better pay, more access to education
- education reduces the total number offspring and increases age of 1st reproduction
population momentum
all age classes are not created equal in effects on population growth
