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 |
- 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
- Some people enjoy watching movies or television in their spare time. Others prefer reading books or magazines. State which you prefer and explain why. 60
- 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 50
- Many academies now offer academic courses over the internet. However some people still prefer learning in traditional classrooms. Which do you think is better? Explain why. 66
- It is generally believed that for many organisms, there is a specific time period, a so-called “window of opportunity,” during which the organism must receive crucial input from its environment in order for normal development to occur. This period is 83
Attributes: Values AverageValues Percentages(Values/AverageValues)% => Comments
Performance on vocabulary words:
No of characters: 509.0 592.248995984 86% => Need more words or more difficult words.
No of words: 132.0 155.574297189 85% => 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: 3.85606060606 3.80514564318 101% => OK
Fourth root words length: 3.38956122427 3.525876923 96% => OK
Word Length SD: 1.95065092383 1.79077849142 109% => OK
Unique words: 86.0 93.7148594378 92% => More unique words wanted.
Unique words percentage: 0.651515151515 0.604071249207 108% => OK
Syllable count: 157.5 185.844578313 85% => OK
Avg_syllables_per_word: 1.2 1.19417670683 100% => OK
Performance on coherence:
Topic speech coherence ratio: 0.0136123362134 0.0650381309087 21% => 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: 1.0 4.35341365462 23% => Need more acoustic paragraphs.
Average paragraph length: 132.0 68.503853103 193% => OK
STD paragraph length: 0.0 21.3332995233 0% => OK
Average paragraph duration: 44.98 25.9943957902 173% => OK
STD paragraph duration: 0.0 7.84667146824 0% => The duration of acoustic paragraphs keeps same.
Acoustic performance on sentences:
How many acoustic sentences: 19.0 42.0642570281 45% => Need more acoustic sentences. Maybe the speech rate is too fast.
Average acoustic sentence length: 6.94736842105 4.02192344571 173% => OK
STD acoustic sentence length: 5.66125970927 3.1217529195 181% => OK
Average acoustic sentences duration: 2.35210526316 1.45093177766 162% => OK
STD acoustic sentences duration: 1.7007291902 0.99851816184 170% => OK
Acoustic performance on acoustic silence:(An acoustic silence means a little pause between two or more words)
How many acoustic silence: 13.0 39.0421686747 33% => Need to have little pauses between words/sentences.
Total acoustic silence duration: 2.44 7.12997991968 34% => OK
Average acoustic silence duration: 0.187692307692 0.185688545393 101% => OK
STD acoustic silence duration: 0.0980701355117 0.155154303396 63% => OK
Acoustic performance on acoustic words:
Total word duration: 38.95 47.1480722892 83% => Need to talk more.
Average word duration: 0.295075757576 0.305395592593 97% => OK
STD word duration: 0.143011422579 0.189427763521 75% => OK
Disfluencies: like hesitations, or 'ehn' or taking a long time to pronounce a word:
How many disfluencies: 4.0 7.94979919679 50% => OK
Total_disfluencies_duration: 2.62 6.2937751004 42% => OK
Total acoustic noise duration: 2.07 3.39508032129 61% => OK
Acoustic rates:
Total speech duration: 44.98 59.7592369478 75% => Talk more. Do not save time. People can talk 4-5 words in one second.
Compare to expected duration: 0.749666666667 0.995987282463 75% => Some seconds left. Need to talk more.
Rate of silence: 0.28901734104 0.656000678711 44% => OK
Rate of speech: 2.93463761672 2.60215298798 113% => OK
Rate of speech by unique words: 1.9119608715 1.56821927147 122% => OK
Rate of word duration by unique words: 2.20795892169 1.99336655568 111% => OK
Average articulation rates: 0.391182931818 0.317803793328 123% => OK
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Rates: 71.6666666667 out of 100
Scores by speech e-grader: 21.5 Out of 30
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Note: the speech e-grader does NOT examine the meaning of words and ideas.