Within a habitat, each species depends on other species, and contributes to the overall stability of that ecosystem. However, some species do more than others by providing essential services. Without the influence of these key species, the habitat changes significantly. Scientists refer to these important players in an ecosystem as keystone species. When a keystone species disappears from its habitat, the habitat changes dramatically. Their disappearance can then trigger the loss of other species. As some species vanish, others move in or become more abundant. The new mix of species changes the habitat’s appearance and character.
The professor gives examples of the effects of elephants on the African grasslands habitat. Using the examples from the talk, explain why elephants are considered a keystone species.
| Post dates | Users | rates | Contents |
|---|---|---|---|
| 2019-10-24 | kap | 71.00 | Check this speaking |
| 2019-10-24 | kap | 50.00 | Check this speaking |
- Beginning next month, Dining Services will no longer serve hot breakfast foods at university dining halls. Instead, students will be offered a wide assortment of cold breakfast items in the morning. These cold breakfast foods, such as breads, fruit, and y
- Good morning, Paul.Male instructor Morning. Hey, I just heard something about a problem with registration for one of the biology classes? Do you know anything about that?Female instructor Yeah. It looks like the Developmental Biology class is already full 61
- Talk about a city or town you have visited in the past. Explain what you liked most about the city and why. Include specific reasons and examples in your response. 90
- Narrator Now listen to a conversation between two students on campus.Male student Hi . . . good morning. Could you help me with something?Female student Um. Maybe. What’s up?Male student Well, I’m a first-year student.Female student Everything going O 55
- Advertisers often try to sell you things by exaggerating about the quality of their products. It helps them get your attention. And exaggeration in advertising is usually considered acceptable, but not always. In the United States, there are laws to help 56
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on vocabulary words:
No of characters: 301.0 592.248995984 51% => Need more words or more difficult words.
No of words: 86.0 155.574297189 55% => More words wanted. You may: choose simpler words or speak faster or remove hesitations or remove long pauses, and fully use the time, do NOT save one or two seconds.
Chars per words: 3.5 3.80514564318 92% => OK
Fourth root words length: 3.04526164648 3.525876923 86% => OK
Word Length SD: 1.15888880218 1.79077849142 65% => Word Length is similar.
Unique words: 40.0 93.7148594378 43% => More unique words wanted.
Unique words percentage: 0.46511627907 0.604071249207 77% => More unique words wanted or less content wanted.
Syllable count: 87.3 185.844578313 47% => The syllable count is low.
Avg_syllables_per_word: 1.0 1.19417670683 84% => OK
Performance on coherence:
Topic speech coherence ratio: 0.00467323545084 0.0650381309087 7% => It may have issues on recording quality or the content is not so closely related to content.
Acoustic performance on paragraphs:
How many acoustic paragraphs: 5.0 4.35341365462 115% => OK
Average paragraph length: 17.2 68.503853103 25% => The average paragraph length is low.
STD paragraph length: 11.4437756007 21.3332995233 54% => OK
Average paragraph duration: 8.15 25.9943957902 31% => The speaking content is not well organized.
STD paragraph duration: 5.03774552752 7.84667146824 64% => OK
Acoustic performance on sentences:
How many acoustic sentences: 41.0 42.0642570281 97% => OK
Average acoustic sentence length: 2.09756097561 4.02192344571 52% => OK
STD acoustic sentence length: 2.20647470788 3.1217529195 71% => OK
Average acoustic sentences duration: 0.882926829268 1.45093177766 61% => OK
STD acoustic sentences duration: 0.954691225533 0.99851816184 96% => OK
Acoustic performance on acoustic silence:(An acoustic silence means a little pause between two or more words)
How many acoustic silence: 34.0 39.0421686747 87% => OK
Total acoustic silence duration: 8.05 7.12997991968 113% => OK
Average acoustic silence duration: 0.236764705882 0.185688545393 128% => Maybe the pauses are too long.
STD acoustic silence duration: 0.151865276755 0.155154303396 98% => OK
Acoustic performance on acoustic words:
Total word duration: 26.16 47.1480722892 55% => Need to talk more.
Average word duration: 0.304186046512 0.305395592593 100% => OK
STD word duration: 0.191908802931 0.189427763521 101% => OK
Disfluencies: like hesitations, or 'ehn' or taking a long time to pronounce a word:
How many disfluencies: 8.0 7.94979919679 101% => OK
Total_disfluencies_duration: 6.34 6.2937751004 101% => OK
Total acoustic noise duration: 5.17 3.39508032129 152% => It may have issues on recording quality or have issues on silences or disfluencies.
Acoustic rates:
Total speech duration: 40.75 59.7592369478 68% => Talk more. Do not save time. People can talk 4-5 words in one second.
Compare to expected duration: 0.679166666667 0.995987282463 68% => Some seconds left. Need to talk more.
Rate of silence: 0.834355828221 0.656000678711 127% => Less acoustic silences wanted.
Rate of speech: 2.11042944785 2.60215298798 81% => Need to bring more content.
Rate of speech by unique words: 0.981595092025 1.56821927147 63% => More unique words wanted.
Rate of word duration by unique words: 1.52905198777 1.99336655568 77% => Need more unique words.
Average articulation rates: 0.246380337209 0.317803793328 78% => OK
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Rates: 50.0 out of 100
Scores by speech e-grader: 15.0 Out of 30
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Note: the speech e-grader does NOT examine the meaning of words and ideas.