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Rantai makanan

Dimulai oleh genjer-genjer, Oktober 09, 2009, 02:52:08 PM

« sebelumnya - berikutnya »

0 Anggota dan 2 Pengunjung sedang melihat topik ini.

genjer-genjer

Ada yang bisa jelasin mengenai rantai makanan ga?

Maksud saya bukan rantai makanan yang berupa proses "makan-dimakan" begitu loh. Bukan cuma sebatas predator dan mangsanya saja, tapi juga melibatkan organisme seperti parasit dan sebagainya. Contohnya begini nih.. rumput dimakan kijang, kijang dimakan harimau, tapi kalau si harimau itu misalnya cacingan, apakah harimau dimakan cacing???

Karena menurut saya rantai makanan nggak sesederhana itu, tapi makin dipikir kok makin bingung yah?? ada yang bisa bantu menjelaskan??
[move]
Cogito ergo sum
[/move]

syx

IMO mungkin ada kaitannya juga dengan efek letalitasnya... misalnya parasitnya bisa menyebabkan harimaunya mati bisa juga dikatakan cacingnya makan harimau.

genjer-genjer

berarti cacing adalah predator harimau gitu??  ;D
[move]
Cogito ergo sum
[/move]

MonDay

predator artinya kan pemangsa
kalo cacing itu parasit,
dia tidak memangsa hanya numpang hidup
tp berefek pada kematian

cmiiw

btw ada yang pnah denger
Sorry but you are not allowed to view spoiler contents.

genjer-genjer

Kutip dari: MonDay pada Oktober 09, 2009, 06:07:41 PM
predator artinya kan pemangsa
kalo cacing itu parasit,
dia tidak memangsa hanya numpang hidup
tp berefek pada kematian
nah kalo gitu di mana posisi si cacing dalam rantai makanan?

Kutip dari: MonDay pada Oktober 09, 2009, 06:07:41 PM
mahluk yang paling berbahaya adalah serangga
alien itu ada di serangga
Iya setuju, kaya' film starship troopers
[move]
Cogito ergo sum
[/move]

syx

sepertinya istilah rantai makanan hanya berkisar pada urusan makan dan dimakan dalam suatu ekosistem tertentu. jadi cuma ada tingkatan produsen, herbivora sebagai konsumen tingkat pertama, karnivora sebagai konsumen tingkat berikutnya, dan decomposer. keberadaan parasit biasanya diabaikan karena sulit terlihat. tapi pada perkembangannya, dalam jaring-jaring makanan disebutkan bahwa parasit juga bisa dikategorikan dalam konsumen tingkat tertentu, yang pasti bukan sebagai tingkat pertama.

Kutip
[pranala luar disembunyikan, sila masuk atau daftar.]

ScienceDaily (July 13, 2006) — Scientists have discovered that parasites are surprisingly important in food webs and their findings appear in a report published this week in the Early Edition of the on-line version of the Proceedings of the National Academy of Sciences. Scientists with the University of California, Santa Barbara, the U.S. Geological Survey, and Princeton University contributed.


This free-swimming stage of a parasite larva, a trematode cercaria, leaves an infected snail to encyst on a fish brain. View is 0.267 mm across. (Credit: Courtesy Todd Huspeni, University of California, Santa Barbara)

The report describes a study performed in Santa Barbara County at the Carpinteria Salt Marsh. Carpinteria Salt Marsh Reserve is one of several natural reserves set aside by the University of California for research and teaching.

Food webs trace the flow of energy through an ecosystem. They extend the concept of food chains – those who-eats-whom sequences – to biological communities. Food webs rarely include parasites because of the difficulty in quantifying them by standard ecological methods. Parasites are small and invisible, hidden inside their hosts. However, parasites strongly affect food web structure and parasite links are necessary for measuring ecosystem stability, according to the study.

"Food web theory is the framework for modern ecology," said Kevin Lafferty, a scientist with the USGS Western Ecological Research Center who is based at UC Santa Barbara and is lead author of the study. "Parasites have been missing from this framework and, as a result, we know relatively little about the role of parasites in ecosystems. It's like driving with a highway map, but with no knowledge of the smaller road network. To reach most destinations, you need a map with both."

Using data from four relatively comprehensive food webs that contain parasites, Lafferty and his coauthors examined if and how parasites affected the food webs. They found that parasites dominated the food web links between species; on average, a food web contained more links between parasites and their hosts than between predators and their prey.

"Parasites may well be the thread that holds the structure of ecological communities together," said study coauthor Andrew Dobson of Princeton University.

Additionally, the researchers' analyses revealed new patterns. It's well known that vulnerability to predators decreases at the top of the food chain or highest trophic level. In this study, the scientists found that vulnerability of hosts to parasites also increased with trophic level. Consequently, animals at mid-trophic levels are the most vulnerable to natural enemies, being subjected both to diverse parasites and many predators.

"The work illustrates that 'the pyramid of life' we learn about in kindergarten is wrong!" said Dobson. "When you add parasites to food webs, the pyramid contains a second inverted pyramid of parasites that are as abundant as all the other species."

When they analyzed the Carpinteria Salt Marsh food web, the researchers calculated that parasites were involved in 78 percent of the links between species. Due to the diversity of parasites in prey species, the Carpinteria web had over twice as many predator-parasite as predator-prey links – 1021 links compared with 505.

Parasitic trematode worms having complex life cycles involving sequential infection of multiple hosts are involved in a large number of links in the Carpinteria Salt Marsh food web. A common snail is the first intermediate host to at least 19 different kinds of trematodes at Carpinteria, involving many different kinds of birds as final hosts. The authors found that without the snail and its trematodes, 977 links would disappear from the corresponding food web. In related work, Lafferty and co-author Armand Kuris, a professor of biology at UC Santa Barbara, are currently using techniques that count trematodes in snails to assess salt marsh health.

"Few food webs have been able to consider parasites and it will take a lot of work to include them, but the message is that you can't fully understand food webs without parasites," said Lafferty. Kuris added that this study, along with other recent research, indicates that most ecological investigations should evaluate the role of parasites because infectious diseases can be such important players.

The PNAS study opens the door to this area of study, according to Dobson. "Once we understand food web structure, we will have a much better understanding of how the loss of biodiversity will affect the quality of life for the surviving species," he said.

biobio

Tingkat makan memakan yang dibicarakan dalam rantai makanan biasanya hanya untuk yang jelas-jelas dimakan, dan untuk kepentingan studi ekosistem. Cacing tadi hanya sebagai parasit. Masa sih cacingan sampai mati?
"The pen is mightier than the sword"

syx

bisa aja kan. parasit itu kan seperti infeksi, cuma dilakukan oleh organisme multiseluler. sepertinya parasit yang mematikan lebih banyak ada dalam perairan.