Chapter 2 Flashcards
producers
of an ecosystem provide food for the other organisms present
producers include plants, and other photosynthetic organisms
take co2 and change to sugar
consumers
within an ecosystem eat plants and other animals
require organic material as meal
decomposers
breakdown wastes and dead organisms recycling nutrients so that they can be used for biosynthesis
ex) fungi, bacteria, small animals present in soil
break down dead, organic material
organims within an ecosystem interact with
both the living and the non-living components of their environment
there are two ways in which ecosystems can be characterized
- recyling of chemical nutrients: the basic chemicals needed for life, (carbon, nitrogen, oxygen) flow from air an soil to plants, animals, and decomposers and the back to the air and soil
- energy flow: energy is constantly gained and lost from an ecosystem
energy enters an ecosystem when light from the sun is absorbed by plants and other photosynthetic organisms
energy exits an ecosystem as heat
cells
cells are both structural and functional units of life
the cell is the basic unit of life and is therefore the lowest structural level capable of preforming all activities necessary for life
the structure and function of a cell wall are well correlated to one another: an emergent property
cellular functions include
- responding to enviornmental changes
-the ability to take in and use energy - regulating their own internal enviornment
-ability to produce and maintain its complex organization - the ability to give rise to new cells
: the basis of reproduction, growth, and repair of multicellular organisms
two main cell types
- prokarote
2. eukarotye
prokaryote cells
-unicelllar
-smaller than eurkaryotic cells
-less complex than eukaryotes
-non membrane bound nucleus
-no memebrane bound organelles
ex) bacteria
10 min to split
eukarote cells
-unicellular or multi cellular
-larger than prokaryotic cells
-more complex than prokarotes
-membrane bound nucleus
-membrane bound organelles
ex) animal cell
10 hours to split
all organisms share some common features which include
genetic material present as DNA
cells as the simplest unit of the organism
DNA is organized into functional units called ___?and the DNA itself is made of individual units called ___?
genes and nucleotides ther are four nucelotides that make up DNA adenine A thymine T cytosine C guanine G
other features common among all life forms include
complex organization: highly ordered structure
a highly regulated internal environment: constant internal environment despite constantly changing external environments
the ability to grow and develop: genes which are inherited control growth and development
the ability to take in and utilize energy: the energy is used to preform all the necessary life functions
the ability to respond to enviornmental changes and stimuli
the ability to reproduce ones own kind
evolution of adaptation: this occurs over many generations, individual with traits best suited to their enviornment will pass them on to their offspring
there are how many species that are known and named
1.8 million
estimates of the true number of species range from 10 million to 400 million
taxonomy
is the branch of biology that names and classifies these species into groups based on similarity
all life can be organized into three domains
1) domain bacteria (prokaryotes)
2) domain archaea ( prokaryotes)
3) domain eukarya
kingdoms of the domain eukarya
there are four kingdoms within the domain eukarya:
1) kingdom protista: single celled protozoans and algae (singler and multi cellular)
2) kingdom plantae: photosynthesis plants
3) kingdoms fungi: molds, yeasts, and mushrooms
4) kingdom animalia: animals: vertebrates and invertabrates
charles darwin
- species present today arose from ancestral species
- he was able to explain both the unity of life (decent from a common ancestor) and the diversity of life (modifications as species diverged from common ancestor)
- darwin proposed that the mechanism of evolution was natural selection
- based on the observations of unequal reproduction success
- the environment selects fro certain traits
- this results in the accumulation of favorable traits in a population over time
natural selection
individuals within a population have varied traits which are inheritable
not all offspring will survive and only those that do will be given the chance to reproduce
the individuals with the most desirable traits will be able to survive and reproduce and the resulting population will therefore be enriched with organisms that have these traits
evolutionary adaptation
all organisms have specific adaptations that have evolved as a direct result of natural selection
antimicrobial resistance has also developed as a result of natural selection
-a resistant species devlelop in a short time period
adaptations
inherited traits that function to enhance an organisms ability to survive in a specific environment
pre-darwin evolutionary theories
greek philosophers initially beilieved that life likely changed gradually
aristotle view was that species were perfect and permanent
during this time it was also believed that earth was only 6,000 years old and that species were static in their form
during the mid 1700’s fossils were studied revealing that there were previous life forms that differed from those seen today
jean baptise lamarck hypothesized in the early 1800’s that life forms evolve
his theory was that this evolution took place according to use and non-use of various body parts which is erroneous
lamarks theory explained the long neck of the giraffe was the result of persistent stretching in order for the giraffe to reach higher trees
all about charles darwin
during the mid- 1800’s darwin set sial around the world as captain of the HMA beagle
he collected plants, animals, and fossils from the shores of south america
-he noted adaptations of organisms from very different environment such as the Brazilian jungle and the Argentinian grassland
-he noted that the individual islands of the galapagos island has species that were different than those of other islands
he also discovered that these islands has species similar to but different than those species found on the nearby mainland
-these observations led him to doubt the pre-exsisting theory that earth and all of its organisms has been created only a few thousand years earlier
-darwin documented his orservations but delayed publishing his theory of evolution because he knew that it would not be widely accepted
in the mid 1850’s alfrwed wallce put forth a similar theory of evolution as darwins
darwin published a book highlighting his theory in 1858 called “on the origin of species by means of natural selection
-evidence that present say species arose from ancestors
-as the descendants of a remote ancestor moved into various different environments they developed diverse adaptions that made them equipped to survive
-he proposed that the mechanisms of this evolution is natural selection
artifical selection
the modification of species by selecting and breeding those individual that possess desired traits
natural selection
a similar process to artificial selection but occurring in nature
this theory was based on two key observations
1. members of a population vary in their traits and most traits are inherited from parents to offspring
2. all species are capable of producing more offspring than the enviornment can support
he then infered that:
1. indivduals whose inherited traits provide them a higher probability of surviving and reproducing ina given environement tend to leave more offspring behind than other indivduals
2. this unequal production of offspring will cause favourbale traits to acumlate in an environment
natural selection
pesticise resistance as an example of natural selection
- bugs with the red gene are resistant to pesticides
- bugs with the green gene are susceptible to pesticides
- application of the pesticide leads to a population enriched with resistant buys
- future applications of the pesticide will be less effective