I started doubting this a few minutes after I wrote this. Since ticks (or mosquitoes, or vampire bats for that matter) don’t live on or in the host, are they parasites?
According to wikipedia, they are. They are “micro-predators”, organisms that feed off many different hosts and never spend an extended period of time on one specific host. In this, they blur the line between predatorial behavior and parasitic behavior.
Either way, they suck…
Your blood.
HA!
-Wade
< dusts off biologist hat >
It is always helpful to remember that biological categories are manmade. Definitions like “parasite”,“species”, “organelle”, etc are all things that organisms and evolution don’t know about. In reality, such terms are often not neat file drawers in which one can safely file a given organism. Categorizing life is very often a fluid and messy business, along a spectrum between binary poles, or blurred with another category, or complicated by contradictions in behavior or appearance. And the categories are ever being debated, shuffled, expanded, contracted. The neat and tidy examples given in textbooks are often the exceptions, not the rules.
< pedantry off >
Pedantry well received and much appreciated.
I studied Latin and Greek in highschool. This filled my young and inquisitive mind with philosophical notions of teleology, purpose and essentialism (Plato, Aristoteles andsoforth).
I went on to study philosophy at university. A professor there based his thinking more on the natural sciences, evolutionary biology in particular. Darwin, Dennet and the like soon blasted all ideas about natural categories and essential purposes out of my mind.
Of course, categorization is an incredibly strong tool for thinking. That’s why it’s so important to remember that it is us who are making the categories.
I remember first encountering articles about ring species which blew my mind, challenging everything I though I knew about “species” as a natural category. ( Ring species - Wikipedia)
EDIT: Actually, now, all these years of learning later, I find the pre-socratic natural philosophers much more exiting and interesting. Wrangling the natural world out of the hands of the gods. (Although they too were full of ideas about the original essence of things.)
I know, right? The thing about “species” as a useful term is that the vast majority of life does not reproduce sexually. Anyone who has had a smidgen of biology education can tell you that the definition of a species is something along the lines of “a group of organisms that can breed and produce fertile offspring.” But that’s wrong a surprising amount of the time even for sexually reproducing organisms, and it’s totally unhelpful for asexual things. So how to define species, say, in bacteria? Well, by declaring a “genomically coherent” group as a species. What’s “genomically coherent”? Whatever we decide it is. Arguments ensue.
I just read abut those of us that walk upright. First Steps by Jeremy DeSilva is on my to read short list.
I guess I’m not too far off topic?
Oh, and every conversation that touches on the subject of biological categories, taxonomy, should mention this:
Birds are dinosaurs.
Next time you see a chicken or a pigeon, stop and think about this.
I mean really let it sink in.
How amazingly, mind-meltdowningly cool is that!
We have budgies. In our dog’s opinion, they are the most exciting TV show ever.
We call them “The Tinysaurs.”
My son thought I was pulling his leg when I kept shouting “Hey, a dinosaur!” whenever we saw a duck or a seagull or… He was getting tired of his old man fooling him into looking.
A few months ago, we went to the Museum of Natural History in Brussels. They have an amazing collection of Iguanodons, found in the old mining site at Bernissart (that’s about an hour’s drive from where I live). In their Dinosaur Hall, they have a beautiful collection of fossils. They have also embraced the knowledge that birds are, in fact, dinosaurs, so they have taxidermy specimens of colourful birds hanging from the ceiling, a coop of live chickens in one corner,…
There is a giant T-Rex fossil in this Hall. Behind its rear legs, under its tail, is the skeleton of a modern chicken.
My son doesn’t think I’m fooling him anymore. He shouts “Dinosaur!” just as loud.