B14 Flashcards
(26 cards)
What is used as evidence of evolution?
- fossils
- antibiotic resistance
Why is darwins theory widely excepted?
Shown characteristics are passed on to the offspring in genes. Also evolution of bacteria shows the same thing.
What are fossil?
Remains of organisms from millions of years ago which are found in rocks
How might fossils be formed?
- Parts of organisms that have not decayed because one or more of the conditions needed for decay are absent
- when parts of an organism are replaced by minerals as they decay
- as preserved traces of an organism , such as footprints , burrows and rootlet traces
What happens when there is a gradual replacement by minerals?
Replaced by minerals as they decau forming a rock like substance shaped like the original hard part, surrounding sediments also turn to rock and eventually someone digs it up
What can we learn from fossils?
How much or how little different organims have changed as life developed on earth.
Why can’t scientists be certain about how life began?
Many early forms of life were soft bodied , so they left few traces behind. The traces left had been destroyed by geological activity.
What is extinction?
When there are no remaining individuals of a species still alive
What is antibiotic resistance?
When bacteria develop random mutations in there dna to be resistant to antibitotics
Why bacteria evolve quickly
They reproduce rapidly
Why antibiotics resistance helps bacteria?
Helps it survive even in a host being treated to get rid of the infection, it reproduced many more times. Increase population of resistant strain of bacteria.
How antibiotic resistance is a problem?
No effective treatment , so the infection could spread between people. Superbugs are becoming more common which are resistant to most bacteria.
What is MRSA?
Superbug thats hard to get rid off, often effects people in hospitals and can be fatal if enters their blood stream
How should we try to stop antibiotic resistant strains from appearing?
- doctors should not prescribe anitbitocics inappropriately such as for non serious or viral infections
- patients need to complete their course of antibiotics so all bacteria are killed and none survive to mutate and form resistant strains
- agricultural use of antibiotics should be restricted
Why it is difficult to keep up with antibiotic resistance?
Devlopment of new drugs is costky and slow
How have organisms traditionally been classified?
According to a system first proposed in the 1700s by carl Linnaeus which groups living things according to characteristics and the structures that make them . Living Things are divided into kingdoms then into smaller and smaller groups
What Is the order of the groups that are subdivided from kingdoms?
Phylum, class, order , family genus , species
In this order ^
Why classification has chnaged?
Knowledge of biochemical processes inside organisms developed , and microscopes improved , scientists began to put forward new models
What did carl woese propose?
The three domain system
What was the three domain system?
Using evidence using analysis techniques he found in some cases species thought to be closely related are not. It has three domains , archaea , bacteria and eukaryota
What is the archaea domain?
Primitive bacteria , often found in extreme places such as hot springs and salt lakes
What is the bacteria domain?
Contains true bacteria like ecoli . Although they are similar to archaea , but there are lots of biochemcial differences
What is the eukaryote domain?
Includes broad range of organisms including fungi , plants , animals , protists
What is the binomial system.
Every organism is given a two part latin name , first part refers to genus and second refers to species. Used to help scientist all around the world have on language
