Biology Evolution & Population Genetics Flashcards

Species change over time and new species arise by the modification of earlier species

Plato and Aristotle;

-God created all things
-all things have a constant, perfect "essence" (an "ideal form")
-variation is an imperfect reflection of the inner essence
-no potential life was left unrealized

Aristotle;
-all living things are fixed in a linear hierarchy
-no empty "links" or "rungs" in the theoretical ladder
-implies that species don't/can't/shouldn't change

Those who are involved in the study of nature to better understand God's plan

-sought to discover order in and classify the diversity of life to better understand God's plan
-species divinely created as prefect at the same time (6000 years ago ~Biblical creation)
-created a nested classification system: each type of organism has a 2-part binomial name consisting of its genus and species

-made discoveries in paleontology
-fossils organisms in closer (MORE RECENT) layers are similar yet different
-fossil organisms in far-apart layers are less similar
-many species in older layers (LOWER) don't exist today

-proponents (Curvier) usually accepted a divine creation
-believed in a relatively young age for the Earth
-the fossil record reflects extinctions due to sporadic catastrophes

- James Hutton was a proponent
-geologic features arise by slow gradual processes over long periods of time (not catastrophically)
-slow continuous process like erosion and sedimentation can lead to even profound change- like the Grand Canyon, etc.

-Charles Lyell
-Mechanisms of geologic change are constant over time
-the same processes are operating today as in the past
-therefore: the Earth must be very old to have accumulated all the changes evident in the geological records

-comparative anatomist
-suggested similar species could be descended from common ancestors
-looked at similarity among limb bones of different species that were used for different purposes and proposed that their similarity reflected shared ancestry (we call these homologous structures)
-e.g. same bone elements and arrangements in vertebrates suggest same evolutionary and developmental origin despite different functions

-said species evolve by gradually changing to adapt to their changing environment

"use and disuse" hypothesis
-if used organs become stronger, if not they deteriorate and eventually disappear
-use/disuse is dictated by demands of the environment: individuals change in response to their environment
-believed in inheritance of acquired characteristics

-age of Earth now believed to be in the range of millions
-close similarities between different groups or organisms had been documented by palaeontologists, comparative anatomists and embryologist
-many naturalist and geologist accepted the fossil record for what it was- a demonstration of the changing nature of life on earth. species appeared and disappeared at different times in history

-born 1809, English middle class
-dropped out of Edinburgh Medical School
-attended Cambridge to become a minister and a naturalist
-1831, he became an unpaid naturalist on 5-year voyage of the HMS Beagle

-he observed organisms on same continent more similar than ones at eh same latitude on different continents
-he saw a correlation between locations and similarity (this suggested a common ancestry)